Magnesium Technology 2018

In recent years, Mg alloys have made inroads into applications for transport industries. The favorable property profile of Mg promotes increased usage. Despite magnesium alloys being used for years, there is still a lack of knowledge about the potential of Mg alloys. New or optimized alloys and processes are creating new ideas for substituting traditional materials. High-pressure die-casting (HPDC) is the predominant technology, while other casting and wrought processes are of secondary importance. Developments in the last decade have led to an improvement of the property profile and effectiveness of magnesium wrought alloys. Additive manufacturing has opened new opportunities for tailoring of the property profile and functionality. In addition, Mg as material for battery anodes adds a new field of application in the energy sector. This presentation will provide an overview of the status of modern process and alloy development, and discuss the challenges to extending the use of magnesium alloys in various applications.

Mg is the lightest structural metal but pure Mg has low ductility due to strong plastic anisotropy and to a transition of <c+a> pyramidal dislocations to a sessile basal-oriented structure [1]. Alloying generally improves ductilityDuctility, but the mechanisms of the enhancement are not yet known. Mg-3 wt% RE (RE = Y, Tb, Dy, Ho, Er) show high ductility [2], as compared to most commercial Mg–Al–Zn alloys at similar grain size. To investigate possible proposed mechanisms of ductility in alloys, and differences between Al, Zn, and Y solutes, first-principles density functional theory (DFT)Density Functional Theory (DFT) calculations are used to compute all relevant stacking fault (SF) energies as a function of solute type (Y, Al, Zn) and concentration in the dilute limit.In DFT calculations, we compute the solute-SF interaction energy $$ E_{int} \left( {d_{i} } \right) $$ versus solute-SF distance d _i . Accurate energies requires the use of large supercells. For the pyramidal II plane, a single solute may induce migration of the SF. Constraints, and corrections for the constraints, are thus needed. In the random alloy, every atom site has a probability c (in at.) to be occupied by a solute atom. The value of the SF energy of the alloy, at small c, is then $$ \gamma^{A} = \gamma^{Mg} + \frac{c}{{A_{0} }}\sum\nolimits_{i} {E_{int} \left( {d_{i} } \right)} . $$The stacking fault energies for basal and pyramidal faults versus concentration are shown in Fig. 1 for the solutes Y, Al and Zn. From these results, we can draw some conclusions regarding ductility in Mg alloys. First, the proposed role of the I₁ basal SF in ductility enhancement in Mg–Y [2] is not supported. The effects of Y can be achieved at twice the concentration using Al. However, neither Mg–Al or Mg–Zn alloys show significantly enhanced ductility. Second, using the I₁ and pyr. II SFs for Y, elasticity calculations show that Y does not appear to significantly alter the energetics of the detrimental pyramidal-to-basal orientation transformation. Third, the only unique property of Y, compared to Al and Zn, is the much larger reduction of the pyramidal I SF energy. This suggests new mechanisms for enhanced ductility that will be discussed and supported by further results on other solutes.

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The high susceptibility of Mg alloys to corrosive degradation is calling for new efficient corrosion protection solutions. In the present paper we discuss the approach based on the introduction of new generation of corrosion inhibitors into the composite protective coatings aiming at an additional active corrosion protection.

In the present paper, Ni-P-MWNTs composite coating was prepared on AZ31 magnesium alloy by electroless plating. Surface modification of carbon nanotubes by cationic surfactant DTAB were studied using IR spectrum. The morphology and the coating composition on the electrode surface were analyzed (SEM and X-ray diffraction). The results show that the prepared Ni-P-MWNTs coating is uniform and compact. The relationship among the concentration of surfactant DTAB, the concentration of MWNTs in bath and coating were analyzed.

In this study, Ni-P-MWNTs composite coating was successfully deposited on the surface of AZ31 magnesium alloys by electroless plating. The electrochemical properties of the composite coatings were studied by electrochemical workstation system. The corrosion behavior of the composite coatings was evaluated by polarization curves in 3.5 wt% NaCl aqueous solution at room temperature. Its corrosion resistance was improved significantly than AZ31 magnesium alloys. The wear behavior of the coatings was investigated using friction and wear test method. The results indicated that the incorporation of carbon nanotubes in the coating improved both tribological behavior and corrosion resistance. Comparing with Ni-P coating, Ni-P-MWNTs composite coatings showed not only higher wear resistance but also lower friction coefficient. These improvements have been attributed to superior mechanical properties, unique topological structure and high chemical stability of nanotubes.

With the versatility of structural performance in magnesium alloys, Achilles hill remains to be their susceptibility to corrosion. The Mg community agrees that traditional methods are insufficient for revealing the root cause of difficulties in controlling Mg degradation rate. Therefore, developing new methods allowing simultaneous assessment of several characteristics is of great importance now. We designed an advanced cell for immersion testing allowing simultaneous assessment of two complementary characteristics of Mg corrosion in aqueous environments: isothermal calorimetry and pressure. Isothermal calorimetry monitors in situ heat production rate during chemical reactions, which can be recalculated to corrosion rate if the enthalpy of a process is known. Pressure monitoring allows alternative quantification of corrosion rate through hydrogen production. The proof-of-concept testing presented here reveals details of a corrosion process depending on electrolyte.

Because of the toxicity of chromate, it is necessary to develop alternatives to chromate conversion coatings. Permanganate conversion coating treatment is one of the methods that are potentially alternative to the chromate treatment on magnesium alloys. This study investigated the effect of fluoride ion in the permanganate solution on the microstructure and corrosion resistance of the conversion coating on AZ91D alloy. Experimental results showed that the presence of fluoride ion impeded the conversion coating reaction and accordingly retarded the formation of the conversion coating, which resulted in a thinner and more uniform coating. Therefore, the permanganate conversion coating formed in the fluoride-containing solution was nearly crack-free and displayed higher corrosion resistance than the coating formed in the solution without fluoride ion.

Magnesium (Mg) based alloys have received prevalent attention, especially in the biomedical, aerospace and automotive industries due to their low density, moderate strength and natural ability to degrade. However, widespread use of Mg-based alloys as degradable biomedical implants still remains a significant technological challenge because of their rapid corrosion kinetics that leads to premature loss of mechanical integrity. Addition of certain alloying elements such as Zinc and Rare Earth Elements (REs) improve the mechanical and corrosion response of Mg alloys. In this paper, the mechanical and corrosion characteristics of two commercially available RE containing Mg alloys, ZE41 and EZ33 are studied. Results obtained using hydrogen evolution, weight-loss measurements, and electrochemistry (PD and EIS) in comparison with pure Mg data are presented here. These initial findings indicate that although, ZE41 and EZ33 have the same primary alloying elements, due to the addition of REs, differences in composition, nature of precipitates and passivating layer play a key role in positively impacting the corrosion behavior and hence, the corrosion rate.

For upscale simulation and modeling of magnesium alloys, data of surface and interfacial energies are critical. In this work, we calculated the surface energies of Mg₁₇Al₁₂ β-phase with different surface configurations by using molecular dynamic simulations. Surface terminations were carefully selected to calculate the energy of β-phase. The lowest energy surface for each crystallographic plane was determined by varying the surface termination. The results show that surfaces occupied by higher fraction of magnesium atoms generate lower surface energies. The interfacial energy for Mg₁₇Al₁₂ β-phase and Mg matrix was calculated as well based on the Burger’s orientation relationship. We found that the lowest energy surface of Mg₁₇Al₁₂ does not generate the lowest interfacial energy. The interfacial energy for Mg₁₇Al₁₂ β-phase and a $$ \left\{ {10\bar{1}2} \right\} $$ twin was also calculated. The interfacial energy increases by ~250 mJ/m2 due to the change in orientation relationship between Mg₁₇Al₁₂ and the matrix after twinning.

Rare Earth (RE)-free Mg alloys suffer from low formability due to strong textures and highly anisotropic deformation modes. In the present study, we examine the effects of Ca addition on microstructure and mechanical properties of Mg–Li–Ca and Mg–Zn–Ca alloys. Based on experimental observations, Ca is reported as the element that should solid-solution strengthen Mg–Li alloys due to its significant size mismatch and weaken the texture in Mg–Zn alloys, similarly to the RE contribution in Mg alloys. Using the density functional theory (DFT) we examine the intrinsic type II stacking faults in the basal and pyramidal I planes. We try different alloy compositions in order to understand the solid-solution effect on the different stacking faults and reduce the high plastic anisotropy in Mg alloys mechanical properties.

Grain refinement is an effective method to increase both the strength and toughness of structural materials. Among the various grain refinement methods, carbon inoculation is an effective method for Mg alloys containing Al. SiC is well-known as a carbon inoculation agent; however, conventional methods for using SiC are suitable only for lab-scale experiments. This study investigates the inoculation methods with regard to the use of SiC effectively and economically for grain refinement of Mg alloys, especially for application in large-scale casting processes. Al-SiC refiner was fabricated by extrusion; it demonstrated a uniform structure with well distributed SiC particles on the Al metal matrix. After adding 0.7 wt% extruded SiC refiner, the average grain size of AZ91 alloy decreased from 550 to 90 μm. It demonstrated an effective refining ability in large-scale casting facilities.

The current lack of comprehensive understanding of the microstructure evolution in Mg–Al–Ce alloys hinders the accuracy of thermodynamic predictions. Our investigations have identified shortcomings within the published literature for the Mg-rich end of the Mg–Al–Ce phase diagram. In this study, the microstructure evolution in Mg–Al–Ce alloys has been studied by X-ray diffraction, scanning and transmission electron microscopy. The experimental results are compared with the Scheil-Gulliver prediction calculated using the CALPHAD method. The observed microstructure contains both the binary Al–Ce and Mg–Ce intermetallic phases in these alloys. The solidification sequence, invariant point and the phase boundaries in the liquidus projection of the Mg–Al–Ce phase diagrams that have been reported previously are inconsistent with this study. The hypoeutectic region is smaller compared to the current Mg–Al–Ce phase diagram. In addition, a hexagonal Al₅Ce₂ phase which is isostructural with Al₅La₂ has been identified in these alloys. The research addresses some of the current limitations in understanding the effect of Ce, when added in isolation, on microstructure development in Mg–Al based alloys.

Recently, Mg and its alloys have attracted much attention because of their excellent biocompatibility and biodegradability. High anisotropy of Mg crystal structure, however, limits the movement of some slip systems; therefore, pure magnesium possesses poor ductility and/or toughness. A number of studies have revealed that alloying with solute elements and modification of grain structure improved these drawbacks. In this study, to clarify the effect of adding solute elements, e.g., calcium and zinc, impact toughness testing and first-principles calculations of generalized stacking fault energy and grain boundary cohesive energy were conducted. For example, alloying magnesium with calcium and zinc and controlling the microstructure produced a Mg alloy with a high compressive fracture strain of 0.40, which was greater than the estimated maximum strain for fastening a surgical clip. This high fracture strain arose from the enhanced grain boundary cohesive energy and reduced anisotropy of slip systems by solute segregation. As a result, the alloy successfully occluded blood vessels.

The microstructure and mechanical properties of as-cast Mg–Ca–Y–Zr alloys with different Y contents were investigated. The alloy containing 0.5 wt% Y exhibited finer grains compared to the alloys with higher Y content. All alloys had a dendritic microstructure with eutectics composed of α-Mg and Ca-rich intermetallic phases. Few Mg–Y-rich intermetallic particles were also found along grain boundaries. EDS analysis showed that the solute Y segregated at dendritic and grain boundaries. The amount of Y contained in eutectics remarkably increased with increasing Y. In addition, the eutectics volume fractions of all alloys were comparable but the morphology became less continuous at higher Y contents. Both the room temperature tensile and compressive strengths were largely improved with increasing Y content. Moreover, the elevated temperature compression tests showed that the compressive yield strength first decreased slightly when the temperature rose to 175 °C, but then remained stable as the temperature increased.

New Mg–O–9Al alloy has been developed by the dispersion of oxygen atoms in the Mg–9Al alloy in which oxygen atoms are supplied from the decomposition of TiO₂ nanoparticles in the Mg–9Al alloy melt. The dissolved oxygen atoms expand the lattice structures of both α-Mg and β-phase, inducing the reduced mismatch distance between α-Mg and β-phase. Therefore, yield stress of the Mg–O–9Al alloy is 143 MPa, much higher than 110 MPa in the Mg–9Al alloy. Fracture toughness values of 10.39 MPa m1/2 and 12.86 MPa m1/2 for both the Mg–9Al and Mg–O–9Al alloys are also respectively obtained. The crack propagates along the weak interface of β-phase in the Mg–9Al alloy. On the other hand, the β-phase disturbs the crack propagation route in the Mg–O–9Al alloy, showing many broken β-phases. Therefore, the improved interfacial feature with an addition of dissolved oxygen atoms in the Mg–O–9Al alloy results in much enhanced mechanical properties.

Among commercial structural metals, magnesium alloys possess the lowest absolute density, featuring specific strength values superior to other structural materials such as aluminium alloys. Nevertheless, magnesium still shows some major drawbacks e.g. high oxidation tendency and more expensive processing compared to aluminium alloys. By adding calcium and yttrium to the commercially dominating AZ alloys, the oxidation behavior can be significantly improved and processing costs can be reduced. In this work, four Mg–Al–Zn–Ca–Y alloys with Al contents ranging from 3 to 9wt% were produced and compared to two standard AZ-type alloys (AZ31 and AZ91). Mechanical properties of as-extruded specimen as well as processability (casting and extrusion) and the resulting microstructures were investigated. The results show that modifying magnesium–aluminium alloys with small amounts of calcium and yttrium improves the materials’ oxidation resistance and flammability behavior without deteriorating mechanical properties and processability.

The alloy development of bioabsorbable BioMg® 250 is described in terms of design of mechanical properties, biocorrosion rate and biocompatibility. The basic mechanistic role of microalloyig elements Zn, Ca and Mn is discussed as related to microstructures. In vitro corrosion and in vivo animal studies are reported. Finally, we list potential orthopedic applications in bone fixation devices fabricated from BioMg 250.

There is only one primary producer of magnesium (Mg) metal in the U.S. utilizing an electrolytic process with feed from the Great Salt Lake. While electrolytic extraction of Mg from anhydrous MgCl₂ is 1.3× more energy efficient than the ferrosilicon reduction of dolomite, this Pidgeon process consumes over 2.3× the energy and produces 5× the CO₂ of the electrolytic MgCl₂ process. However, direct electrolytic reduction of MgO provides an opportunity to produce Mg at 20% less cost than the Pigeon process, conserve energy, and reduce CO₂ emissions. It has been demonstrated Mg can be electrolytically produced just above its melting point utilizing a composite anode of MgO+C as well as in a vapor state at approximately 1200 °C when MgO is dissolved in a select all fluoride fused salt. The high temperature processing is being bench pilot scale demonstrated to confirm the lower energy requirement and cost savings for full commercial scale demonstration.

Magnesium components using strips produced by the Twin-Roll casting technology are of high interest for the automotive industry. Depending on the components application Original Equipment Manufactures define rigid mechanical property standards for magnesium sheets to ensure a high finished product quality. To meet these requirements continuously in a large-scale production via quality assurance the highly complex relationships during Twin-Roll casting need to be investigated holistically. This paper proposes a structural equation model for the assessment of the interrelationships of Twin-Roll casting process parameters and mechanical properties in transverse direction of heat-treated AZ31 Twin-Roll-Cast (TRC) strips using partial least square structural equation modeling (PLS-SEM). Within this context, the impact of the casting parameters, thickness profile and segregation formation on mechanical properties of magnesium strips after heating and before hot rolling will be approximated. It will be shown that the TRC thickness profile indicates mechanical properties irregularities due to local segregations.

The morphology and distribution of Al₈Mn₅ is studied in AM50 and AZ91 produced by hot and cold chamber high pressure die casting (HPDC). It is found that, in HPDC, primary Al₈Mn₅ particles take a wide range of morphologies within the same casting spanning from faceted polyhedra to weakly-faceted dendrites. These different morphologies exist across the whole cross-section without any clear trend in morphology versus radial position. A comparison with Al₈Mn₅ in samples solidified at low cooling rate suggests that the larger polyhedral particles are externally solidified crystals (ESCs) that nucleate and grow in the shot chamber analogous to αMg ESCs, and that the dendritic Al₈Mn₅ nucleated and grew at high cooling rate in the die cavity.

About 1.4 billion tons of nickel-containing serpentine are stored in the territory of Tuquan County, China’s Inner Mongolia Autonomous Region. In this paper, serpentine as raw material, silicon aluminum alloy as a reducing agent, the use of the corresponding additives and catalyst, the first were mixed and then dry pressed into the ball and placed in the furnace under the appropriate vacuum to heat the balls, the magnesium steam was collected to get crystalline magnesium, and the mixed residue crushed, the nickel-iron alloy was separated from the tailings by magnetic separation. The tailings were used in the manufacture of cement. The process has no CO₂ emissions, low-carbon environmental clean production, and the laboratory using a new type of continuous production of heating equipment for the reduction reaction to get magnesium steam, can achieve continuous production, expand production scale and improve production efficiency.

Mg(OH)₂ is usually used as a flame retardant agent, a heavy metal removing agent and a flue gas desulfurization agent in the field of environmental protection. In this work, Mg(OH)₂ was prepared by electrolytic method using MgCl₂ aqueous solution as the main raw materials. And the X-ray diffraction results proved that pure Mg(OH)₂ crystals can be fabricated by the electrolysis method. The Mg(OH)₂ prepared has two microscopic forms, shaped in block and elongated fibrous. The effects of concentration of MgCl₂ solution, current density, temperature and time of electrolysis on the current efficiency and energy consumption in the electrolysis process were studied in this paper. Within the experimental range, current efficiency increased but energy consumption decreased with the increase of MgCl₂ solution concentration, electrolysis temperature and time. The effects of current density on the current efficiency and energy consumption rested on the concentration of the MgCl₂ solution and electrolysis temperature.

The US Army Research Laboratory (ARL) and the Osaka University Joining and Welding Research Institute (JWRI) continued a collaborative partnership with Taber Extrusions, Epson, Pacific Sowa, Kurimoto, and National Material LP to reproduce and scale-up military grade magnesium alloy AMX602 at the Taber Extrusions manufacturing facility in Russellville, AR. The latest effort was to extrude 304.8-mm (12-in) wide AMX602 plate, exploring 5 extrusion scenarios, and dynamically characterizing the penetration resistance of these plates against two projectiles with different nose shapes. The results were parametrically analyzed and compared to conventionally processed magnesium alloy AZ31B-H24 and aluminum alloy AA5083-H131. None of the 304.8-mm wide AMX602 plates could meet or exceed the penetration threshold of AA5083 against the fragment simulating projectile. Future research is required to define the manufacturing variables that correlate to maintaining the quality of the defeat mechanisms in the AMX602 plate as the width increases.

The mechanism of magnesia production was investigated experimentally in reversion reaction process in vacuum. Condensation temperature and temperature gradient which effected on the condensation of the magnesium vapor produced by magnesia carbothermic reduction in vacuum have been investigated by Mg recovery efficiency, XRD, SEM and EDS. The results show that the higher recovery efficiency was obtained when the condensing temperature which is closer to the dew point of magnesium in the constant temperature gradient. Under the condition of appropriate condensation temperature, the lower the temperature gradient is, the better the crystallization of magnesium vapor is. The XRD patterns of the profile and undersurface of the condensation product of 1873 K show that the profile of the condensation contains Mg only and the purity of the metal magnesium is high. But the undersurface of the condensation contains Mg and MgO. The SEM and EDS images of the profile and undersurface of condensation indicate that the microstructure of the undersurface of condensation is largely flocculent structure and irregular arrangement and the crystal morphology was poor and particles were also tiny. This is due to magnesium vapor reacted with CO vapor at cooling phase, MgO and C obtained covered the undersurface and stopped magnesium vapor condensing.

Chemical reactions carried out under microwave irradiation often have high reaction rates and high selectivities, which enable compact reactor sizes and energy-conservation processes. Thus, microwave chemical processing and chemical synthesis have attracted considerable interest, as they will be employed for greatly improving process efficiencies and conserving energy for realizing “Green Chemistry” or “Green Engineering”. We have applied this technology to smelting process of magnesium metal. But Oxide (dolomite) does not absorb microwave energy well and does not generate heat. This time, when electrically conductivity ferrosilicon used as a reducing agent was mixed with the raw dolomite material and made into an antenna structure, it became easier to absorb the microwave energy and reduce the temperature. We have successfully obtained small amount of magnesium metal using a microwave irradiation with high yield of 71%, and also showed quarter of energy consumption in comparison with conventional process, which is called Pidgeon process.

This study provides the simultaneous thermogravimetric (TGA) decomposition and formation of MgB₂. This thermal decomposition of MgB₂ to MgB₄ was investigated to determine the kinetic barriers associated with the decomposition process. At the same time, the formation of MgB₂ from MgB₄ was also studied. A list of models available from the literature was also validated in the present study by using the Coats-Redfern equation to determine the mechanism involved in the decomposition and formation reactions. A second order reaction model was more linearly fitted with the CR equation than other available models. A computational approach was used to determine the precise reaction order (n = 2.2) for both decomposition and formation. The activation energy of decomposition was 205.81 ± 1.5 kJ/mol and formation was 241.5 ± 2.6 kJ/mol, both of which are in close agreement with the literature. The standard formation enthalpy of MgB₂ (−18.16 ± 1.78 kJ/mol) and MgB₄ (−13.86 ± 0.71 kJ/mol) was also obtained.

Improvement of ductility is important for applications of Mg alloys. Basal dislocation motion and twinning are the two major deformation modes in Mg alloys. However, the basal slip system cannot support homogeneous plastic deformation of Mg alloys. Twin-boundaries in Mg alloys are potential sites for cracking. Therefore, activation of non-basal slip is expected to play an important role in improving ductility of Mg alloys. We have studied both <a> and <c+a> dislocations, as well as their interactions with solute atoms, stacking-faults and grain-boundaries in RE-containing Mg alloys. Cottrell atmospheres along dislocations in deformed strengthening phases of a Mg–Zn–Y alloys were observed and quantified. Based on atomic resolution characterizations, a binding energy of about 0.05 eV is deduced between basal dislocations and surrounding solute atmospheres. Besides providing enough independent slip systems, <c+a> dislocations can cut and react with basal stacking-faults, and react with grain-boundary dislocations, and drive migration of grain-boundaries, benefiting both strength and ductility of Mg alloys.

We describe here the microstructure, mechanical properties and deformation behavior of an ultrafine-grained (UFG) Gd and Zn-containing magnesium alloy that was characterized by high strength-high ductility combination. The deformation behavior was studied by nanoindentation and post-mortem electron microscopy analysis of the deformed region. The behavior is compared with low strength-low ductility coarse-grained (CG) counterpart. Extensive dislocation slip was an active deformation mechanism in the UFG alloy, while in contrast, mechanical twinning occurred in the CG alloy. We attribute these observed differences in the deformation mechanism to the grain size effect.

Extruded magnesium alloys with strong basal texture present tension and compression asymmetry. Dislocation slip dominates plastic deformation during tension along the extrusion direction (ED), whereas twinning is the main contributor to plastic strain when compressed along the ED. In this work, an extruded AZ31 Mg alloy was prestrained by tension along the ED to 5 and 10% of total strain, followed by compression, in order to investigate twin-slip interaction. The results show that the yield stress in compression only slightly increases with increasing prestrain. Notably, the hardening rate at the low stress stage during compression remains almost unchanged, compared to specimens without prestrain. Our results suggest that the contribution of twin-slip interaction to hardening is negligible in deformation of Mg alloys.

The evolution of twinning in randomly textured magnesium alloy and rolled AZ31 alloy during biaxial mechanical tests has been monitored using concurrent application of acoustic emission and neutron diffraction methods. The influence of the loading path on twinning is discussed in detail. It is shown that the twinning is strongly sensitive to the load path.

Magnesium alloys with different content of zinc (Zn) and yttrium (Y) were extruded at an extrusion ratio of 18:1 at 350 °C. The alloying elements in both Mg alloys formed a long period stacking ordered (LPSO) phase, which during the extrusion process was elongated along the extrusion direction (ED). The magnesium matrix has bimodal character composed by fine dynamically recrystallized (DRX-ed) grains and initial coarse grains elongated along ED. Compression tests with concurrent acoustic emission (AE) measurements were performed along ED at 200, 300, and 400 °C. The deformation mechanisms and the mechanical properties at 200 °C are very similar to those obtained at ambient temperatures, i.e. in the alloy with low volume fraction of the LPSO phase (<10%) twinning controls the yielding, while in the alloy with high volume fraction of the LPSO phase (around 35%) dislocation slip and kink formation are dominant. At 300 °C the reinforcing effect of the LPSO phase is reduced and at 400 °C it is not effective anymore.

Many studies have shown that textures with less distinct alignment of basal planes and the related improvement of formability are found in alloys that contain rare-earth (RE) elements and zinc. However, the effect of the combination of these additional elements on the texture modification has not been yet clearly understood. In this work, sheet samples from Mg–Zn–RE alloys rolled at 400 °C were used for in situ synchrotron X-rays diffraction measurements under tensile loading at different temperatures, in order to track the development of diffraction profiles and textures during deformation. In Mg–Zn–RE alloys, a significantly retardation of recovery and dynamic recrystallization during the high temperature deformation is observed in comparison to the RE-free Mg–Zn alloy. The differences in the active deformation mechanisms as well as the dynamic recrystallization mechanisms are reviewed with respect to the texture alteration. For discussion of the impact of different mechanisms, EBSD observations reveal the microstructure development.

The proper thermo-mechanical treatment can improve mechanical properties of extruded Mg alloys through a solute segregation and precipitation along twin boundaries. The effect of heat treatment on mobility of twin boundaries with respect to applied loading direction was studied in extruded Mg–1Zn alloy using the acoustic emission (AE) technique. The adaptive sequential k-means clustering (ASKC) was applied to analyze the AE data in order to determine the dominant deformation mechanism in a given time period. The AE energy, median frequency and the number of elements in individual AE clusters are the main parameters of presented clustering analysis. Active deformation mechanisms are discussed with respect to mutual orientation of grains and loading direction.

Deformation and fracture behaviors of AZ31 and E-form Mg alloys sheets were investigated during Erichsen test. Formability of Mg alloys was discussed in terms of Erichsen index (IE) and tests were conducted at room temperature using conventional Erichsen tester. The role of difference in initial textures and grain sizes in Mg alloys sheets was investigated to understand the deformation and fracture mechanisms in Mg alloys during Erichsen test. The evolution of the microstructure and microtexture of the deformed Mg alloys was analyzed via an electron back-scattered diffraction (EBSD) techniqueElectron back-scattered diffraction (EBSD) technique. Crystal plasticity finite element method (CPFEM) was used to predict the micromechanical deformation behavior of Mg alloys during Erichsen test. EBSD analysis revealed that deformation twins along with shear localization by dislocation slip were the main deformation mechanisms during Erichsen test. E-form Mg alloys with a weaker basal texture show higher IE compared to AZ31 alloy with a stronger basal texture.

The nudged elastic band (NEB)Nudged Elastic Band (NEB) method [1, 2] is used to find the energy barrier separating stable twinned and untwinned states in Magnesium. This technique enables identification of the minimum energy path between the two stable states. The effects of dislocations, grain boundaries, and other defects which enhance twin nucleation produce a measurable effect on the minimum energy path [3, 4] and energy barrier. Thus, the NEB technique enables direct comparisons of the material twin-ability under a variety of boundary conditions. By simulating twinning in a variety of boundary conditions, NEB calculations provide key insight into the twin nucleation process by demonstrating both what defect arrangements encourage twin nucleation, and how likely twinning is to occur under given boundary conditions. This data is crucial for incorporating twin nucleation accurately into higher scale modeling.

Microstructure and mechanical properties of Mg-7.71Gd-2.39Nd-0.17Zr alloy after different heat treatments were investigated. The microstructure of the as-cast alloy was composed of α-Mg matrix, bone-shaped α-Mg + β-Mg₅(Gd, Nd) eutectic, a little amount of small cuboid phase (GdH₂) and Zr-rich cluster within α-Mg matrix. The optimal solution treatment was determined to be at 515 °C for 4 h. After solution treatment, bone-shaped α-Mg + β-Mg₅(Gd, Nd) eutectic was almost dissolved into α-Mg matrix and the grain size increased slightly. Furthermore, a large amount of GdH₂ was precipitated along the grain boundaries and within α-Mg matrix. After subsequent aging treatment at 200 °C for 32 h, Mg₅Gd phases were precipitated along the grain boundaries. For the peak-aged alloy, the peak hardness of 105 HV was achieved and the ultimate tensile strength, yield strength and elongation at room temperature were up to 273.7, 188.2 MPa and 4.1%, respectively, which may be mainly attributed to the β″ and β′ phase precipitated within α-Mg matrix after ageing treatment.

Novel Mg₉₇Zn₁Y₂ alloy of equiaxed fine grains with long-period stacking ordered (LPSO) phase was prepared by consolidation of chips machined from a twin-roll-cast alloy. The chip-consolidated Mg₉₇Zn₁Y₂ alloy exhibited superplasticity at a wide initial strain-rate ranging from 1 × 10−3 to 3 × 10−1 s−1 at temperatures of 623 and 673 K. The maximum elongation was approximately 560% at 3 × 10−2 s−1 at 673 K. The strain rate sensitivity index (m-values) was shown to be greater than 0.3 in this study; this value seems to be large enough to ensure uniform elongation during superplastic deformation. SEM/EBSD measurements revealed that the chip-consolidated Mg₉₇Zn₁Y₂ alloy was composed of mixed equiaxed fine-grains of α-Mg and LPSO phases of a mean size of ~1 μm. The grain boundary sliding in the equiaxed fine-grains appears to account for most of the mechanism of superplastic deformation in this alloy.

Typical magnesium bulk materials, like AZ31B, show high potential to reduce vehicle weight in automotive applications. Technical limitations are coming from the material behavior under crash loads, where a risk of catastrophic failure is given in buckling deformation modes. To potentially implement magnesium into new applications, the behavior of magnesium AZ31B structures in dynamic bending and axial compression load cases have been studied. In structures with a bending load, such as a bumper, the stabilization of the section of the profile leads to a significant improvement of specific energy absorption and to a lower risk of catastrophic failure. Rectangular section beams have been constructed and tested by using the quasi-static/dynamic three-point bending facilities at German Aerospace Centre (DLR)—Institute of Vehicle Concepts. For axial loads, cutting or peeling mode based mechanisms have been developed and investigated, which allow the use of magnesium in these challenging applications.

Mechanical properties of extruded Mg alloys are significantly influenced by the activation of extension twins during compression along the extrusion direction (ED) because of a strong texture with basal planes oriented parallel to ED. At the same time, the heat treatment is also supposed to tune mechanical properties via strengthening or softening mechanism. The influence of heat treatment on the mechanical behavior of Mg–Zn-based alloys with an addition of Ca and Nd in as-extruded state and after pre-compression (i.e. partly twinned microstructure) is discussed in the paper. Difference in distribution of precipitates for two materials after applying heat treatment at 200 °C for 16 h was observed. Isothermal ageing of pre-strained samples leads to strengthening in ZN10 alloy and softening in ZX10 alloy.

The effect of low temperature forging on the microstructure, quasi-static response and stress-controlled fatigue behavior of cast AZ31B Mg alloy was investigated. The forging process was conducted at a temperature of 275 °C and a forging rate of 20 mm/s. Fully reversed stress controlled cyclic tests were performed on cast and forged material under total stress amplitudes of 120–160 MPa. Neckless type bimodal grain structure, an indication of incomplete dynamic recrystallization was observed in the forged microstructure in addition to the development of a sharp basal texture. The obtained mechanical test results show that the forged material achieved significantly improved yield and tensile strengths along with longer fatigue life. The improvement in the quasi-static propertiesQuasi-static property was attributed to the strengthening effect of partial grain refinement and activation of non-basal slip modes due to texture modification.

Magnesium is an important structural material due to its attractive properties including having a low density and an excellent strength-to-weight ratio. Grain refinement is used as a method to increase the strength and ductility of Mg and therefore knowing the recrystallization and grain growth kinetics is important. The experimental results showed that inhomogeneous nucleation created a two-stage nucleation process during recrystallization and that alloying slowed down grain growth significantly in Mg. A complete article on this work can be seen in a future issue of Metallurgical and Materials Transactions A.

This study investigates a biodegradable Mg–5Zn–0.3Ca alloy (ZX50) during HPT-processing and long-term heat treatments, the latter with respect to the evolution of intermetallic precipitates and vacancy clusters. Both the precipitates as well as the vacancy clusters achieve strength increases as the Zn atoms may act as potential trapping sites not only for HPT-induced dislocations but also vacancies. So far, overall increases of strength of up to 200% have been reached while keeping the Young’s modulus unchanged, thus representing an attractive improvement of mechanical properties for the actual alloy.

Localized strain accommodation, a concern for any structural material with regard to formability and failure, is a particularly prominent issue for Magnesium alloys that possess the unipolar twinning mechanisms and the large differentials between activity ease of slip mechanisms. In this study, for both rolling and extrusion textures of a Magnesium AZ31 alloy, strain heterogeneity levels are characterized by in situ scanning microscopic image correlation. With a nominal 10 μm subset size and spanning over 105 grains, grain-scale strain mapping is conducted over a [−2, 2]% reversed loading cycle. The rolled sample exhibits much sharper patterns that transcend to upper length scales with collaborative activity. The nature of these patterns change depending on the load sense as operational twin mechanisms switch. The extruded sample exhibits the more typical several-grain-long strain localization patterns that follow the grain boundaries. For each case, strain quantification of the localization structures are provided via histograms.

Newly developed die-cast alloys based on Mg–Al−Ba–Ca (ABaX) system show promise for high temperature creep resistance. ABaX844 alloy is one of them and it has limited workability due to high alloy content. To identify the optimum processing conditions, processing map for this alloy was developed earlier, which exhibited two workability domains in the temperature and strain rate ranges: (1) 340–410 °C and 0.0003–0.005 s−1, and (2) 425–500 °C and 0.0003–0.1 s−1. Dynamic recrystallization (DRX) occurs in these domains. The map also exhibited extensive flow instability mainly at strain rates > 0.01 s−1 up to a temperature of 400 °C and at strain rates >0.1 s−1 beyond 400 °C. The aim of the present study is to validate the findings of processing map by performing forging tests in the temperature range 300–500 °C (at an interval of 40 °C) and forging speeds of 0.01, 0.1, 1 and 10 mm s−1 to produce a rib-web (cup) shape component. Finite-element (FE) simulations were performed for obtaining the variations of strain and strain rate in the components during forging. The microstructures of forged specimens deformed under optimum process conditions derived from the processing map revealed the formation of dynamically recrystallized grains. The alloy specimens forged under the conditions of flow instability have fractured and/or exhibited flow localization. The results validated the predictions of the processing map and the load-stroke curves obtained by FE simulation correlated well with the experimental curves.

Since magnesium has very low density, it is always attractive in aerospace and transportation industries. However, due to high reactivity with environment, melting, alloying and casting of magnesium is always faced with problems about melt quality. So these alloys have low resistance to oxidation and combustion. Recent studies show that addition of alkali earth metals reduces the oxidation tendency of molten magnesium alloys. This study aimed to investigate the effect of calcium on oxidation resistance of magnesium alloys melt through microstructural studies, XRD and melt oxidation test. Results show that addition of calcium forms intermetallic compounds such as AL₂Ca. Formation of these type of compounds in grain boundaries with surface oxide film of CaO, prevents the melt oxidation and minimizes the oxidation during atmosphere exposure. The most important advantage of these alloys is minimizing the use of shielding gases like SF₆ which is considered a greenhouse gas that causes many environmental problems.

The use of magnesium sheet in automotive light-weighting initiatives is low due to its poor formability at room temperature. In this investigation the cast ZEK100 (Mg-1.2Zn-0.35Zr-0.17Nd, in wt%) alloy was subjected to rolling at temperatures from 350 to 450 °C and for each rolling temperature the evolution of microstructure and tensile properties were assessed. To assess strengthening during rolling, properties were also measured after annealing following each rolling. The results show that increasing the rolling temperature caused reduction of tensile strength, yield stress but increasing elongation. A correlation was established between mechanical properties and grain size influenced by the rolling temperature. The results are discussed in terms of the role the rare earth elements play in controlling the formability of magnesium alloys.

The Interdependence model will be briefly reviewed and then applied to two different casting situations. One is the solidification of Mg–Al–Sm alloys to determine the optimum composition for achieving a fine as-cast grain size. Because the size range of the nucleant particles can be measured, the key factors describing the potency of the particle can be calculated providing a more complete description of the grain formation mechanisms operating for this alloy. This approach should be relevant for other Mg–Al–RE alloys. The other casting situation is where the melt of an AM60-AlN nanoparticle composite was treated ultrasonically producing a fine grain size on solidification. The limitations to grain size reduction by nanoparticles are discussed in terms of the Interdependence and Free Growth models.

Grain refinement of Mg–Al based alloys is challenging because it is known that Zr, which is extremely effective in many Al-free alloys, cannot be used. The addition of carbon through various routes by using carbon-containing sources is considered as an option. The grain refinement mechanisms are still under debate. The present work is focused on the ternary base system Mg–Al–C, including the potential nucleants Al₄C₃ and Al₂MgC₂, presently without consideration of Al₂CO. The ternary carbide Al₂MgC₂ was synthesized and characterized using sealed Ta crucibles. The decomposition of the carbide was measured at 1290 °C by Differential Thermal Analysis under a pressure of 8 bar. Practical difficulties, including high vapor pressure of Mg and high affinity of Mg with oxygen, as well as rapid hydrolysis of the Al₂MgC₂ carbide have been overcome.

An overview of the development of a high-performance Mg–RE based alloy, HP2+, is presented, which has a good combination of die-castability and mechanical properties at ambient and elevated temperatures. The original alloy, HP2, was a die-casing version of the sand-cast alloy SC1 developed for powertrain applications. However, HP2 tended to crack substantially, leading to unusable castings due to its high Nd content. It was found that the solidification path of Mg–RE alloys can be engineered to reduce the propensity to hot tearing by changing the mixture of RE elements towards La-rich, which leads to an increase in the amount of eutectic and a reduction of the solidification range. Precipitate-forming RE elements, such as Nd or Y, were optimized for HP2+ to meet the requirement for high temperature creep resistance. Whilst some challenges remain with the commercial application of HP2+, the learnings from the alloy design process can be applied to other alloy development programs.

Quaternary Mg–Sr–Mn–Ce alloys were developed for automotive powertrain applications. The design strategy was based on previous studies of the authors studies on the creep behaviour of subsystems (Mg–Mn, Mg–Ce–Mn, Mg–Sr–Mn) and the role of Mn in the dynamic precipitation of fine nano-scale dispersoids. In the present work, the creep resistance and the microstructural evolution of the selected quaternary Mg–Sr–Mn–Ce compositions were investigated. The final creep strain in the quaternary alloys was seen to be four times lower than the ternary Mg–Sr–Mn alloys creep tested at 200 °C under 50 MPa stress. The creep strengthening was attributed mainly to the dynamic co-precipitation of Mg₁₂Ce and α-Mn phases.

Various aspects of global trends like energy saving or safety, economic and production targets or requirements due to the automation give high and challenging targets for the development of future vehicles. With respect to these requirements weight saving is also a must during an early phase of the concept and structural development process. Within the Next Generation Car project the DLR is looking for solutions for future integrated functions like health monitoring and the combination of passive and active safety functions. New material systems and novel combinations of design methods are also developed. The integrated approach of combining development and optimization methods with tools for the design is the key to the development of concepts for holistic lightweight solutions and new vehicle concepts utilizing highly automated and autonomous driving abilities. Challenges and potentials for next generation lightweight design are shown and solutions and results from the DLR project Next Generation Car are presented.

Magnesium alloys are already widely used in numerous applications in transportation and consumer products. Ways have been found to improve corrosion and creep resistance, formability in general, and processing routes have been optimized. But would Mg alloys also be suitable for use in an environment where friction, corrosion, thermal fatigue and creep resistance at elevated temperatures are issues? Due to lightweighting benefits, pistons would be an ideal application for Mg based materials. It is much more efficient to accelerate and to decelerate a lightweight material compared to a heavier one. Al alloy pistons are already fairly well established. But Mg could provide further benefits compared with Al due to its specific strength and mass. We will report the state of the art in Mg pistons, with our own and others approaches to improve properties and the challenges that Mg pistons have to face.

Innovative semi-finished products require tailoring mechanical properties and improving formability. Due to science-based alloy design as well as optimization of processing parameters (process-property relationship), it is now possible to control microstructures, phase distributions and texture development of magnesium sheets. A combination of new technologies and innovative alloys could help to alleviate the strong textures formed in semi-finished Mg products. The presentation will show Magnesium sheet development via twin roll casting technology and the how the subsequent warm rolling process influences the properties of the final magnesium sheet metal. Further optimisation of process parameters of twin roll casting and of the rolling process in combination with alloy design lead to a microstructure showing promising mechanical properties like high formability und high strength.

Lightweight magnesium (Mg) alloys have attracted considerable attention for potential applications in the automotive industries. However, the low strength or poor formability at room temperature (RT) hinders the wider applications of wrought Mg alloy sheets. The newly developed a heat-treatable magnesium sheet alloy, Mg–0.6Zn–0.3Ca–0.1Zr (at. %), shows a large Index Erichsen value of 8.0 mm at RT in a solution treated condition. The excellent RT formability can be ascribed to a weak basal texture. Subsequent artificial aging at 170 °C for 4 h (T6) increases the 0.2% proof strength from 165 to 213 MPa. This improvement in strength by the T6 treatment is associated with a dense distribution of Guinier–Preston zones lying on the basal planes of the Mg matrix. Our finding overcomes the trade-off relationship of the room temperature formability and proof strength in Mg alloy sheets and this can be used as “bake hardenable” magnesium sheet alloy with excellent RT formability.

The impact of non-shearable particles on the stress required to propagate a twin is examined using numerical and analytical techniques. Of particular note is the nature of this effect in magnesium alloys where twinning can count for a significant fraction of the plastic strain. Dislocation Dynamics simulations are employed to calculate the Orowan bypass stress. It is seen that the stress for bypass can exceed that for a single twinning dislocation but under some circumstances it may be similar. The conditions that give rise to different regimes of behaviour are mentioned and the significance for magnesium alloy design is described.

Magnesium alloys were produced with extrusion, screw rolling (SR) and multi-directional forging (MDF) processes. Various temperatures were used for SR and MDF. The tensile test was carried out to measure the mechanical properties and immersion test in 3.5 wt% NaCl saturated with Mg(OH)₂ was run to measure the corrosion rate. It was found that the grain size increased gradually with increasing the MDF or SR temperature. The increase in the MDF or SR temperature resulted in decrease in yield strength due to increase in grain size. However, the corrosion rate decreased after MDF and SR. Furthermore, the increase in MDF or SR temperature resulted in more reduction in the corrosion rate due to reduction of galvanic cells by dissolution of the intermetallic phases into the matrix.

To widen the application of the magnesium sheet alloys, good room temperature (RT) formability and satisfactory strength need to be achieved. The development of heat treatable alloy can be an effective approach to simultaneously achieve the good RT formability and satisfactory strength. In this work, we have investigated the effects of Zn content on the microstructure, stretch formability and mechanical properties in the Mg–xZn–0.36Zr–0.32Ca (x = 3, 4, 5 wt%) sheet alloys. The as-rolled samples showed strong basal textures regardless of the Zn content. However, the decrease in the Zn content resulted in the significant texture weakening in the solution treated samples, and this leads to the improvement of the stretch formability up to 7.3 mm in Index Erichsen value in the Mg–3.1Zn–0.36Zr–0.32Ca alloy. Subsequent artificial aging at 160 °C for 16 h slightly increased the tensile yield strength of Mg–4Zn–0.36Zr–0.32Ca alloy sheet from 176 to 194 MPa. This work has demonstrated that the Mg–Zn system is promising to achieve excellent RT formability and high strength, however, the slow age hardening kinetics needs to be improved to make it industrially viable.

Precipitation hardening is one of the dominant strengthening mechanisms for Mg alloys, especially for Mg alloys containing rare earth elements. However, precipitation hardening of conventional Mg alloys (such as AZ91D, ZK60 or even WE54/43) is relatively weaker than in high performance Al alloys [such as Al–Cu–Mg based alloys (2024) and Al–Zn–Mg–Cu based alloys (7075, 7050)]. Further avenues for improving precipitation hardening of Mg alloy are therefore being actively explored. In this paper, co-precipitation on the basal and prismatic planes of the α-Mg matrix in a Mg–2.4Gd–0.4Ag–0.1Zr alloy after over-ageing at 200 °C for 2048 h was investigated using high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) imaging and electron energy loss spectroscopy (EELS). Ag was observed within precipitates on the basal plane, while Gd was observed within precipitates on both the basal and prismatic planes. Furthermore, Ag, Gd-rich clusters were also observed in the vicinity of these precipitates, which were proposed to form during solution treatment and to coarsen during subsequent ageing treatment.

Evolution of the dislocation structure in Mg₉₇Y₇Zn₅ (at. %) alloy having long period stacking ordered (LPSO) structure was studied during compression tests. Two materials, an as-cast and an extruded one were deformed up to the applied strain of ~25%. The evolution of the crystallite size, the dislocation density and the population of the particular slip systems were determined by the evaluation of the X-ray diffraction peak profiles. A very low dislocation density with the order of magnitude 1012–1013 m−2 was detected in the compressed specimens. This dislocation density did not increase considerably with increasing strain. At the same time, a significant decrease of the crystallite size occurred during compression. These observations can be explained by the arrangement of dislocations into low energy dipolar configurations, such as kink walls, which do not contribute to the dislocation density measurable by X-ray diffraction peak profile analysis, however they yield a fragmentation of the crystallites.

Neodymium, a Rare Earth with low solid solubility in Mg is an ideal alloying element to improve the yield strength and creep resistance cost effectively. The addition of Zn achieves a further improvement; however, its influence on the intermetallic phases in the Mg–Nd–Zn ternary system is not yet fully understood. A Mg-5Nd alloy modified with 3, 5 and 7 wt% of Zn was investigated with in situ synchrotron radiation diffraction during cooling from the molten state to 200 °C in order to investigate the phase-formation and -transformation characteristics of the alloys. The synchrotron diffraction results have been complemented with TEM investigations on the as-solidified samples. The results suggest that Zn has a strong effect on the microstructure by stabilizing the Mg₃Nd phase and accelerating the precipitation formation. The experimental results do not fully comply with the theoretical calculations, indicating the necessity of improving the thermodynamic databank for this alloy system.

The study describes structure characteristics as well as mechanical properties, corrosion behavior and biocompatibility of Mg–Y and Mg–Li alloys with 0.2% Ca, 1% Ca and 1% Zn cast into permanent molds. The structure showed a significant effect of the amount of alloying additives on the morphology of phases occurring mainly at the grain boundaries. Alloy composition also affects the possibility of grain structure refinement. The mechanical properties obtained the highest level in alloys with the addition of 1% Zn and 0.2% Ca. The results of biodegradation tests carried out in Ringer’s solution showed that the lowest dissolution rate had the alloys with low Ca content. High Ca content raised the content of the Mg₂Ca phase in the alloy, which acted as a catalyst of the grain boundary corrosion. The examination of Mg alloys carried out under sterile conditions at 37 °C after 144 h of the test in α-MEM solution has proved a high biocompatibility of these alloys when containing additions of Li, Ca and Zn.

Mg and its alloys degrade under physiological conditions. The great challenge here is to tailor the degradation in a manner that is suitable for a biological environment. Fast or uncontrolled corrosion is associated with strong hydrogen and ion release and severe pH changes, which can lead to a fast loss of mechanical stability and undesirable biological reactions. Since these processes are highly complex in a living system and sufficient data describing the degradation in vivo is missing, it is very difficult to produce knowledge based new alloys. Still, the endeavour is successful: one CE certified Mg-alloy compression screw (Magnezix, Syntellix AG, Germany) and a Mg-based drug-eluting stent (Magmaris, Biotronik AG, Germany) are on the market. In addition, in China and Korea patient trials (hip surgery and hand fracture) are reported. This paper gives a brief outline of the current status of Mg-implants and which obstacles still have to be mastered. As an example for the special nature of Mg and its interaction with cells, a comparison is made between the influence of osteoblasts (bone forming cells) and fibroblasts (the most abundant cells in connective tissue) on the degradation layer underneath the cells.

The Mg rich corner of the ternary Mg–Si–Sr alloy system is experimentally and thermodynamically investigated in this work. Thermodynamic simulation of the ternary phase diagram required modelling of the ternary phases that occur in these alloys, namely the ternary intermetallics MgSiSr and MgSi₂Sr for which only scarce information is available in literature. The Mg-rich side of the Mg–Si–Sr phase diagram is constructed based on descriptions of the binary phase diagrams Mg–Si, Mg–Ca and Ca–Si from literature and assuming complete solubility (i.e. a line compound) between the ternary phase MgSiSr and the binary phase Sr₂Si. It is also assumed that MgSi₂Sr is a stoichiometric compound. A good agreement is found between the constructed phase diagram and the experimental microstructural results for a range of cast and heat treated alloys.

Neutron diffraction (ND)Neutron diffraction (ND) remains an important tool for in situ analysis of material behavior during various stages of its lifespan, including fabrication, service, damage accumulation and failure. ND was also developed to study solidification of alloys, where minor phases at low solid fractions can be successfully detected, thus providing valuable information difficult to obtain using traditional characterization methods. In the present work, in situ ND solidification experiments were carried out with AZ91D Mg alloy. To this alloy, novel grain refiners were added and the phase evolution prior to the alloy’s liquidus temperature, as well throughout the freezing range was recorded. The role of the refining elements and their interaction with the solidifying alloy was investigated.

TRC Mg alloys are hot rolled to further reduce the thickness of the TRC strip which results in a sheet material with a relatively strong basal texture which produces anisotropic tensile properties based on the test direction. The low force TRC concept developed at BCAST provides a pathway to produce thin strip that does not require further hot rolling to achieve the final desired thickness. The as TRC and homogenised AZ31 show a refined grain and very little centre line. The as TRC AZ31 has a tensile yield strength of 220 MPa along the casting direction (CD) and 190 MPa perpendicular to CD showing a very small yield anisotropy.

The nonlinear properties of copper ion removal through the adsorption on treated steel slag is a function of pH and the election potential. Based on phase space reconstruction theory and the powerful nonlinear mapping ability of support vector machines, the information offered by the time series datum sets can be fully exploited and the trend of displacement evolution of adsorption system can be precisely predicted by making real-time predicting. The experimental results suggest that the methods based on phase space reconstruction and v-SVR algorithm are very accurate, and the study can help to build the displacement forecast system to analyze the removal rate of copper ion in the adsorption system.