Advances in Materials and Metallurgy

Bearing performance is an important factor to improve efficiency of pumps. Depending on specific pump requirements, pump producers have various alternatives for selection of bearing materials. Little friction, slightest to no wear, low-power utilization, and extended life are important features for pump bearings. Serious attention must be given to the tribological evaluation of typical bearing materials. In this work, a pin-on-disk wear testing instrument is employed to study the sliding wear response of phosphor bronze, nylon 6/6, brass, DLC-coated steel, and WC/C coated steel. The tests were performed with an applied load of 10 N and sliding velocity of 0.6 m/s. EN 31 steel heat treated to 55 HRC was selected as disk material. The experiments are conducted as per ASTM G99 standards. The low value of coefficient of friction was noticed in nylon 6/6 and DLC-coated steel.

Biodegradable polymers are produced in a way to decay by the natural cause of micro-living organisms. Cassava starch which is a biodegradable polymer used for biomedical, packaging items. But the molecular weight is less than other biodegradable polymers. The aim of this research work is to investigate the properties of biodegradable polymer manufactured from cassava starch containing the combination of acrylonitrile butadiene styrene (ABS), a non-biodegradable polymer with the cardanol oil, a bio-phenolic compound which is employed as the compatibilizer. They are blended with melt blending process using injection moulding. The use of cardanol oil in the mixture resulted in increase in the level of compatibility evidenced by increase in the intermolecular weight, and the results have shown the substantial plasticizing effect, increase of mechanical properties (tensile strength, impact strength and flexural strength) and increase in the intermolecular weight which will make from biodegradable property of ‘disposables’ to applications for ‘durables’.

AA6082–TiO2 surface composites are prepared by friction stir processing (FSP). Fabricating defect-free surface composite with uniform particle distribution by FSP is a challenging task. In this study, TiO2 particle-reinforced AA6082 alloy surface composites were fabricated using different FSP parameters to find the optimum tool rotation speeds and traverse speeds. This investigation was carried out with optical microscopy and was found that TiO2 reinforcement particles are disintegrated and distributed homogenously by the stirring action of the tool, which also forges the plasticized material. The hardness profile was obtained using Vickers microhardness test across the thermomechanically affected zone and welded zone and found that the retreating side had more hardness. The tensile test was also performed to identify the change in the strength due to the surface composite.

In the present study, a considerable importance is being given to find a novel material for marine application. The synthesis of nano-particles reinforced with matrix alloy using conventional casting offers low wettability between reinforcement and the molten metal. Hence, an effort has been made to develop nano-glass particles reinforced magnesium alloy matrix to enhance the wettability between the matrix and the reinforcement. The die cast magnesium unified with various mass fractions percentage of nano-glass particles of particle size 30 µm has been synthesized using stir casting method. The influence of nano-reinforcement on micro structure and mechanical properties of developed nano-composites have been analyzed. From the experimental results, it has been inferred that synthesized composites have homogeneous grain structure, low density, minimal porosity, and excellent matrix-reinforcement interfacial integrity. The main interfacial phase has been identified as Mg17Al12 between the reinforcement and matrix alloy.

The effects of B4C nanoparticle reinforcements with an average size of 50 nm on the abrasive wear performance and microstructure of Cu nanocomposites were examined. Various combinations of Cu–B4C nanocomposites were synthesized by solid state powder metallurgy technique. Abrasive wear experiments were carried out by sticking the abrasive sheets of 400 grit silicon carbide on the disc of pin-on disc-wear tester. Pins of unreinforced Cu and Cu nanocomposites were pressed and rotated against silicon carbide abrasive sheets under dry sliding conditions at different loading conditions. Addition of nano-B4C in Cu matrix significantly enhances the hardness of the nanocomposites which in turn increases the wear resistance of nanocomposites. The nanocomposites with 1.5 wt% of B4C possess the superior microhardness and maximum wear resistance property. Morphology of worn out surfaces were explored by scanning electron microscopy.

The disposal of used automobiles tyres is a major environmental concern of the day. Annually, there are 1.2 billion tyres seeking disposal issues globally. Concrete as a major construction material can potentially adopt processed rubber waste—derived from tyres as a partial replacement for aggregates. The present study is focused on mechanical and thermal properties of concretes with rubber as partial replacement to well-graded conventional aggregates. The study includes replacement of 10, 20, 30 and 100% of coarse aggregate with waste tyre aggregates and was compared with conventional M30 grade concrete. Concretes were subjected a thermal cyclic heating of 50 °C for a period of 7 days. The results showed that the weight of the rubber concrete is reduced by 12% compared to the conventional concrete and the strength of the concrete reduces with the increase in rubber content. At ambient temperatures, the rubber concrete was found thermally stable. The compressive strengths were found increasing after cyclic heating of 50 °C for a period of 7 days. This effect may be due the effect of Portland pozzolana cement which has 30% of fly ash in it. From this study, it can be concluded that rubber waste concretes can be a potential candidate for structural and non-load bearing structures at ambient temperatures.

The generation of crumb rubber is abundant in our country and safer disposal has become a challenging job. Hence, a study has been attempted by mixing the crumb rubber in two different types of soil (CI and CH) in different percentages and their properties were studied. They were mixed with the soil sample in 10, 15, 20, 30, 40 and 50%. The standard Proctor compaction, CBR, UCC and permeability tests were conducted. From the experiments conducted, it is observed that maximum dry density decreases with increase in optimum moisture content. The CBR and UCC value increases with increase in percentage of crumb rubber till 15% for both the type of soils and the coefficient of permeability increases with increase in percentage of crumb rubber.

High-performance requirements of materials in automobile industry gave the scope of alloying of monolithic metal powders which plays a significant role in the enhancement of properties. In the present study, monolithic powder matrix aluminum is alloyed with respective proportions of copper and magnesium by mechanical alloying. With 4 wt% of Cu as constant, different wt% (0.25, 0.5, 0.75, and 1) of Mg are added to form various powder alloy preforms. The alloy preforms are triaxially compacted in a tool steel die and sintered at 550 °C for 1 hour in continuous flow high pure argon gas atmosphere. The sintered alloy preforms are subjected to uniaxial deformation at two different temperatures, (400 and 500 °C). The hardness and the relative density increases with the extent of deformation. Potentiodynamic polarization is performed on deformed preforms to evaluate the effect of deformation. Corrosion rates and hardness of the alloy preforms were correlated with the relative densities. The extent of deformation and compositional variations on all the properties were analyzed.

There are numerous ways to produce Metal Matrix Composites (MMC). In the present study, a new approach has been designed with the combination of vacuum arc melting and powder metallurgy to produce non-equilibrium MMCs. The Al–2%ZrB2 homogenous composite mixture was compacted in uniaxial direction and used as raw material for vacuum arc melting. The green compacts are subjected to high temperature within a short span of time. The melts were assured for homogenous composition by melting from different faces. Hardness of the composite was measured and which appeared to be higher than its powder metallurgy counterpart. The XRD patterns were analyzed for the phases present in the composite after melting. The composite has been tested to evaluate the corrosion rate through potentiodynamic polarization study.

The mode I interlaminar fracture toughness of hybrid laminate was investigated by conducting double cantilever beam test as per ASTM D5528. Unidirectional carbon or kevlar fibre was stacked as outer layers and glass fibre layers in quasi isotropic orientation was used as core. Layer configuration of the 12 ply symmetric laminate was taken as [H/H/G0/G135/G90/G45]s. H/H was varied as G0/G0, C0/G0, C0/C0, K0/G0 and K0/K0. These hybrid laminates were prepared by hand lay-up technique and post cured by compression at high temperature and pressure. The strain energy release rate (GIC) calculated using modified beam theory method was found to be better for the glass/carbon-epoxy hybrid laminates under mode I loading. Fractographic analysis of the delaminated surfaces shows fibre imprints and hackles. In glass/kevlar-epoxy hybrid laminate cusp was observed that could be formed due to shear loads acting on that laminate.

Semi-solid extrusion of Al–Cu–Mg Powder Metallurgy (P/M) alloys had simulated under three different temperatures and extrusion angles in the present investigation. Al, Cu, and Mg powders were taken in different ratios in order to produce strong and light weight P/M alloys. Billets were prepared with an aspect ratio of one (φ 15 × 15 mm) to get good deformation results. Al–4Cu–0.5Mg alloy composition was optimized to do semi-solid extrusion after considering density, hardness, and strength as best parameters to optimize. Alloys were sintered at 550 °C and prepared samples with Initial Relative Density (IRD) of 90% for densification and deformation studies. The working temperature range for semi-solid extrusion test was derived from TG/DTA analysis. Extrusion tests were performed on a hydraulic press under different deformation temperatures (550, 575 and 600 °C) and different solid fractions (0.93, 0.76, and 0.56) respectively. All the extrusion tests were performed with a low extrusion ratio of 1.44, die approach angles of 30°, 45°, and 60° and strain rate of 0.1 s−1. High density (>95%) and high hardness (>1000 MPa) extruded Al alloys were produced with good microstructures. Microstructural analyses were done for all Al alloys and found uniform distribution of grains at different temperatures. Dynamic recrystallization of grains was found with increasing liquid fraction during extrusion experiments. For an accurate prediction of microstructure evolution the strain rate, strain and temperature have to be considered and these can be calculated by FEM simulation. Simulation studies had been performed at three selected temperatures using Deform-2D software. Simulation and experimental results have been shown good agreement between them.

Investigation of mechanical and tribological properties of A356 alloy reinforced with Al2O3 nano (average size 30 nm) and MoS2 micro-particles (10 µm) are presented in this study. The percentage of Al2O3 was constant (1 wt%) and MoS2 varied from 0.5 to 2 wt% with the interval of 0.5%. The ceramic particles were added when stirring at 300 rpm and 800 °C with squeeze casting pressure of 43 MPa in stir and squeeze casting machine. Characterization of A356/Al2O3/MoS2 hybrid composites were conducted and Tribology studies on the samples were also investigated at 10, 30 and 50 N load, sliding speed of 1.3 m/s and sliding distance of 1100 m in dry condition. Microstructure analysis of the composite showed that the Al2O3 (1 wt%) and MoS2 (0.5 and 1%) particles were dispersed uniformly in the A356 alloy matrix. Partial agglomeration was observed in the synthesized metal-matrix composite (MMC) with higher MoS2 (2%) and Al2O3 (1%). The MMC containing 0.5 and 1 wt% of MoS2 and Al2O3 (1 wt%) exhibited the higher bending strength, lesser wear, and coefficient of friction.

The ceramic matrix is quite rigid and strong, but its fracture toughness has to be increased in order to fully realize its potential possibilities. This difficulty can be resolved by developing ceramic matrix composites (CMCs). CMCs have been processed to realize quasi-ductile fracture behavior and advantages of monolithic ceramics at high temperature. From different CMCs, TiB2–SiC CMC is used in automotive brakes, cutting tools, propulsion engine exhaust, etc. In the present study, TiB2–SiC CMCs with varying SiC particle reinforcement of 0, 5, 10, 15 vol.% were synthesized using powder metallurgy (P/M) consolidation method with the help of spark plasma sintering (SPS) furnace at IIT, Madras. Raw materials particles sizes are TiB2 (average size of 14 µm-matrix) and SiC (average size of 1 µm-reinforcement). SPS process parameters used were sintering temperature 1450 °C, 40 MPa pressure with 10 min as hold off time. Microstructural analysis was carried out using scanning electron microscope (SEM) to observe the homogeneous distribution of reinforcement over the matrix. From the characterization studies, the CMC specimen with 15% SiC gave a good fracture toughness of 6.3 MPa√m and vickers hardness of 22.1 GPa.

In recent time, carbon fiber reinforced plastics (CFRP) are used in important applications in aerospace, automobile, sporting equipment’s, biomedical instruments, etc. High-speed machining of this material can regulate the cutting conditions to maximize production output. Investment for this process is at minimal cost which has been the generic aim of manufacturing industries all over the world. In order to accomplish this, Finite Element (FE) models have been developed for critical applications. Such numerical analysis negates the need for exhaustive experimental trials needed to estimate various parameters involving in machining. This has been the reason instrumental in coercing industries to resort to FE analysis for simulating cutting processes. The present work aims to assess and validate the deformation behavior of carbon fiber reinforced epoxy composite during high speed machining. Orthogonal turning was performed for varied cutting conditions by varying cutting speed and feed at a constant depth of cut. An FE model was constructed using ABAQUS V6.13 and the effective stress–strain response and deformation were analyzed. The simulated results for cutting force, thrust force and feed force showed good correlation with experiments.

LM6 alloy matrix and soda–lime glass particulate composites were produced by stir casting method. Nine sets of composites with the combinations of 1.5, 3.0 and 4.5 weight per cent of glass particles and 75, 125 and 210 μm glass particle size were developed as test composites. The result showed that, soda–lime glass particles were uniformly distributed and properly wetted with LM6 alloy matrix. Tensile strength of the composites were decreased as the weight per cent and size of the glass particles increases. Hardness increases as the weight per cent and size of the glass particles increases. Wear resistance was improved by increasing the weight per cent of particle. Thermal conductivity of the composites decreased with increase of weight per cent and size of the glass particles.

The tribological performance of brake friction composites (FCs) with SSS1140 Stainless steel fiber (Equivalent to EN304) is studied using a pin-on-disk tribometer. Five friction composites, namely SSB5, SSB10, SSB15, SSB20, and SSB25 were developed with 5, 10, 15, 20, and 25% of stainless steel fiber, respectively, by compensating the inert filler BaSO4. The friction and wear characteristics are evaluated at dry sliding condition based on ASTM G99-95. The performance is investigated with three different normal loads (10, 20, and 30 N) and speeds (1, 2, and 3 m/s). It is observed that the increase in fiber content increases the friction coefficient (0.21–0.49). The specific wear rate of the friction composite observed as SSB5 < SSB10 < SSB15 < SSB20 < SSB25. It is observed that the SSB20 and SSB25 are more aggressive towards rotor wear which is also indicated by the higher hardness of the respective FCs. The physical, chemical, and mechanical properties of the developed friction composites are also studied with IS 2742 and ISO 6315, and the performance values also lies between the prescribed industrial standards.

Increase in demand for environmental friendly engineered structures make the natural fiber reinforced composites as the best option to synthetic fiber in polymer composite structures. In this study, the influence of stacking sequence of natural hybrid laminates on mechanical and vibration characteristics that are beneficial for structural applications have been focused. To study the effect of stacking sequence efficiently, a high modulus natural fiber, i.e., Flax and a low modulus natural fiber, i.e., Sisal are preferred. The preferred natural hybrid composite laminates were made by hand layup technique. The hybrid laminates were tested for mechanical properties and free vibration characteristics by means of ASTM procedure. The experimental modal frequency values were used for finding the effective elastic constants of natural hybrid composite laminates adopting by simple regression analysis. These effective elastic constants were used for performing theoretical modal analysis of natural composite beams at high frequency level using finite element method. Based on the results of experimental and theoretical modal analysis of Flax/Sisal composite beams, the effective stacking sequence for structural application was suggested.

In this work, the enhancement of wear performance of cryogenic treated (CT) as-cast AZ91 reinforced with 1.5 wt% WC magnesium metal matrix nano-composite (Mg-MMNC) had been explored using pin-on-disc tribometer and scanning electron microscope (SEM). AZ91 with 1.5 wt% WC reinforcement was prepared with stir casting process and the cryogenic treatment was carried out at −190 °C. The wear test parameters were the applied normal loads of 20 and 40 N, sliding velocities of 1.0, 1.6, 2.1 and 3.1 m/s and a constant slipping distance of 1200 m with tribo-couples of aluminium disc and Mg-MMNC pin at atmospheric conditions. At lower loads, almost all the samples had showed the similar wear loss. But in higher loads, there was significant reduction in wear loss for cryogenic treated Mg-MMNC. The presence of reinforcement and increased Mg17Al12 phase particles volume fraction due to CT had significantly enhanced the wear resistance of composite. There was also wear loss in counter-part aluminium disc. The SEM analyses of worn surface indicate that there was abrasion and oxidation. And a changeover occurred from oxidation wear to delamination wear and abrasion wear while the applied load was increased from 20 to 40 N. Adhesion wear took place at the sliding condition of load 40 N and speed 3.1 m/s.

The use of polymer matrix based composites in manufacturing industries tends to increase due to its lowered density and strength to weight ratio. In the present investigation, a trial has been made to analyze the dynamic mechanical behavior of flyash particles filled polyester resin composite. The polyester resin based polymer composite has been synthesized with 2, 3, and 4% of reinforcement. The vibration behavior under operating temperature of the composite have been studied and analyzed. From the DMA analysis, it has been observed that the synthesized polymer matrix composites can withstand higher vibrations within the operating temperature.

Aluminum silicon alloy castings are highly used in automobile industries due to their excellent casting and machining ability, corrosion resistance and high strength-to-weight ratio. The mechanical properties of aluminum–silicon LM6 alloy are mostly dependent on solidification and casting parameters. This paper presents an experimental investigation made on aluminum–silicon (Al–Si) cast LM6 alloy using sand casting process. The main objective of the research is to investigate the effect of chill thickness and pouring temperature on LM6 sand castings. The casting parameters such as pouring temperature and external copper chills are considered for the experimental work. The simulation work has been carried out with AutoCast-X1 software for obtaining appropriate design parameters. The experimental work has been carried out in the foundry. The pouring temperatures 730, 750 and 770 °C are considered for experiments along with varying chill thickness. The use of end chills during casting not only favors directional solidification but also enhances solidification. Rapid cooling rate helps to get finer structures and improved mechanical properties. In this work, an attempt has been made to obtain the better cooling rate of LM6 castings using copper chills. The mechanical properties such as hardness and ultimate tensile strength (UTS) are analyzed. It is seen that the external chill has a significant influence on the properties of the casting components. The design of experiment has been set up and experiments were conducted as per full factorial array. Castings are made under the constraint of the process and methodical parameters at three different levels. The mathematical models of UTS and hardness have been developed. The micrographs of microstructure of castings with and without applications of copper chills have been compared using optical microscopy. The better mechanical properties such as UTS and hardness were obtained by proper combination of pouring temperature and application of external copper chills.

Aluminium and its alloys have been the centre of interest to the engineer’s community due to their high strength to weight ratio, high wear resistance, low coefficient of thermal expansion and ease of manufacture. To fulfil the increasing requirement of lighter weight, yet excellent mechanical properties than aluminium alloys, addition of grain refiners with modifiers to the alloys has been proposed. Al–Si alloy was taken as the master alloy, while magnesium and copper were added individually with a tint of modifiers and grain refiner. Two sets of same specimens of varying composition were prepared. One set of samples was annealed and the other underwent deep cryogenic treatment (DCT) followed by tempering. Wear behaviour of Al–Si alloys was analysed before and after the DCT by using the computerized ‘pin on disc’ wear testing machine. After cryogenic treatment, all the specimens, except those containing grain refiners showed influence on wear resistance.

The study of the interfacial heat transfer coefficient (IHTC) is one of the major concerns during solidification of casting. In order to find out the IHTC at the metal–mold interface, a one dimensional transient heat conduction model is numerically investigated during horizontal directional solidification of Sn–5wt%Pb alloy. The forward model is solved using explicit finite difference method to obtain the exact temperatures for the known boundary conditions. The estimation of the unknown IHTC is attempted using Particle Swarm Optimization (PSO) as an inverse approach along with Bayesian framework. In order to prove the robustness of the proposed methodology, the estimation is accomplished for the simulated measurements. The simulated measurements are then added with noise to replicate the experimental data. The present approach not only minimizes the difference between simulated and measured temperatures but also takes in to account “a priori” information about the unknown parameters.

The aim of this work is electrochemical exfoliation of pyrolytic graphite for mass production of few-layer oxygen-functional graphene, commonly known as graphene oxide (GO). It is synthesized by intercalation of graphite sheets in the 1 M concentration of nitric acid electrolyte by application of positive bias. The voltage is gradually increased with an increment of 0.5 V up to 8 V and an interval of 3 min. The X-ray diffraction peaks corresponding to GO ((001) plane) and graphene sheet ((002) plane) were observed at 2θ positions of 26.35° and 13.56° respectively. The morphology of as-synthesized GO is characterized by field emission scanning electron microscopy. The transparent layers of GO are observed in transmission electron microscopy. AFM topography revealed that the thickness of the few-layer GO nanosheets are in the range of 3–5 nm only. The hexagonal ring structure of GO sheets was identified by selected area diffracted pattern. Through FTIR studies, the presence of functional groups of O–H and C–O has been identified. The synthesized material can be used as a base material for the future applications such as desalination of sea water, supercapacitors, sensors, solar cells, and coatings.

Zirconia-toughened alumina (ZTA) has been the famous composite utilized for the fabrication of articulating components in a hip joint prosthetics. The demand for longer life and better performance the material characteristics of the articulating components have to be enhanced. In recent literatures it has been described that the addition of multi-walled carbon nanotubes (MWCNT) into an alumina matrix of zirconia-toughened alumina, ZTA to improve the flexural strength, fracture toughness, and fatigue resistance. The intent of the current work is to establish and authenticate that the material’s toughness and hardness could be significantly tailored by preparing 3Y-TZP toughened alumina (ZTA) composites by the combination of functionalized MWCNT using conventional sintering method. For this method, homogenous spreading of CNTs in ceramic matrix has been reached from 0.5 wt% up to 1.8 wt% CNTs using ball milling then compacted and finally sintered. The density and micro hardness were studied related to the experimental runs established using box-behnken design. A clear enhancement in the physical properties was achieved after the adding MWCNTs at the range of 0.5 to 1.8 wt% and sintering temperature varied from 1500 to 1600 °C. The addition of MWCNT in the matrix exhibited the better porosity, density over 3Y-TZP toughened alumina (ZTA) sintered at the same temperature. This results designates that the properties of Zirconia-toughened alumina (ZTA) with MWCNT reinforcements based composites are strongly rely on the process of adding CNT and sintering. The optimized process parameter were also identified form the studies.

Hardness is an important mechanical property which determines the applicability of polymer composites. Carbon Nanotubes (CNTs) invented by Iijima by arc-discharge technique. It possesses some unique properties like Young’s modulus, the values varies from 0.42 to 4.15 TPa, tensile strength of 1 TPa, density varies between 1.3 and 3 g/cm3 which is comparatively lower than commercial carbon fibers. This makes CNT as a potential reinforcement with metal and polymers for enhancement of properties. This work describes about preparation of PP-CNT composites with different ratios. Hardness of the composites were measured using Nanoindentation method and found that hardness of the PP-CNT system increases significantly with the increase of CNT proportion in the PP matrix.

In recent years, the continuous demand for dissimilar joining combination of various materials increasing in manufacturing sector for various applications such as power plants, nuclear, and aerospace applications. The joining of dissimilar metals using conventional fusion welding methods is exhibited in unsatisfactory joint strength. The use of solid-state welding methods is most suitable for joining of dissimilar combination in the current scenario. In this study, dissimilar joining of 304 austenitic stainless steel and D3 tool steel are joined using friction welding process to investigate the properties and joint interface characteristics. To identify the feasibility of joining dissimilar materials using friction welding process, the experiment is performed at different input welding conditions such as friction pressure and upset pressure were varying from minimum to maximum values to obtain the reliable joint strength. The friction welded joints were characterized using microscope observations at the weld interface and failure modes are discussed.

The research studies the effect of corrosion on friction-welded AA6061 aluminium alloy to pure copper with nickel interlayer. The potentiodynamic polarization method was utilized to determine the corrosion rate in the chosen environment. All tests were performed in an aerated 0.6 M NaCl aqueous solution (6.5 pH, 30 °C) to determine characteristics of the corroded areas, specifically the welded region and the parent metals. In this method, the potential of the working electrode was varied with the corresponding current being monitored. It was observed that the parent metal-aluminium alloy (AA6061) was more corroded than the welded regions. Further, specimens welded with lower ‘upset pressure’ were less corroded than those welded with higher ‘upset pressure’. The corrosion rate varied from 0.466 and 356.64 mA/cm2. SEM fractography was used to determine the type and extent of corrosive action, by studying the characteristics across the cross section.

Self-lubricating metal matrix composites (MMCs) are replacing many conventional materials that are used in automotive, aerospace and marine applications due to superior wear resistance. The objective of this work is to investigate the effect of reinforcing solid lubricant—Molybdenum Disulfide (MoS2), hard ceramic particles of Zirconia (ZrO2) and metallic particles of Nickel (Ni) into base Al 7075. The hybrid Al-MMC is fabricated using stir casting process. The total weight percentage of MoS2, ZrO2 and Ni are varied by 10, 20 and 30%. Maximum hardness is obtained in the case of 30% reinforcement and is 137% of its base Al 7075. Dry sliding wear tests are conducted to know the effect on wear rate. The wear rate was reduced by 58.94% in the case of minimum wear condition for 30% reinforcement. SEM, EDS and XRD were done and the presence of reinforcing particles was confirmed.

Lead is an element which was being used traditionally in soldering because of its low melting point. However, lead is poisonous and increasing research is being carried out on developing lead-free soldering alloys. In this work, two lead-free alloys, namely 87Sn–7Zn–3Al–3In and 87.5Sn–6Zn–2Al–2.5In were melted by induction melting with pure argon atmosphere. Vicker’s hardness test was conducted and also the pasty range of the alloy was found using Differential Scanning Colorimetry (DSC). Hardness values were higher than normal lead-based soldering alloys and the pasty zone was comparable to normal lead-based alloys. The lead-free solders were characterized with Energy Dispersive X-Ray Spectra (EDS). Microstructural characterization was also done to corroborate results.

Austempered ductile iron (ADI) proven itself as a significant manufacturing material due to its remarkable properties like withstanding high fatigue behavior, fracture toughness, wear resistance, ductility, etc. This paper reports the experimental results obtained on subjecting ADI specimens to thermal treatment, i.e., austempering and austenitization. All austempered ductile iron ADI specimens are subjected to mechanical and metallurgical testing. Within the given range of varying austempering temperatures, tensile strength and metallurgical changes were analyzed. The tensile studies show that as the austenitization temperatures increased from 900 °C, strength values increased, but a reverse trend was observed at temperatures higher than 1100 °C. With increasing the austenitization temperatures, the carbon percentage was observed to increase, leading to decrease in elongation, and an increase in the hardness. For metallurgical analysis, SEM factographs were employed to test the heat-treated ADI specimen. The microstructure images show that high austenitization temperatures give coarse properties to the ADI. At austempering temperature 420 °C, it shows the rise of retained austenite from 35 to 46% of volume.

The main emphasis of the research is to analyse the variation in the behaviour of properties of steel after the combined heat and cryogenic treatment. Preheat treatment was done, where the steels were kept at 600 °C for 60 min and then was quenched using saline bath, followed by the cryogenic treatment at 77 K. For the proper comparison of the variation of properties, the cryogenic treatment of steel was carried out at varying soaking time steps of 2, 4, 6 and 8 h for appropriate analysis of the material. Using optical microscopy, it was observed that as compared to the untreated steels, the impacts of combined heat and cryogenically treated samples were having an excellent microstructure and surface texture. The presence of saturated austenite was initially higher for the untreated material but was found to be lowering with the increase in cryogenic soaking time of material. SEM examination visibly specifies the formation of fine and coarse grains on treated and untreated steels, respectively. Microhardness of cryogenically treated materials was amplified by around 29%, when subjected to combined heat and cryogenic treatment. XRD analysis was done to analyse the variation in the friction coefficient for both the sets of specimens, and it was found that 8 h cryogenically treated specimens were having significantly reduced coefficient of friction as compared to untreated steels.

Self-curing epoxy thermoset resins have been focused considerable attention by industrialist because of their superior mechanical strength, good resistance to moisture and chemical process, high bonding strength and low shrinkage during curing. In the present improbable environment, the hemp plant fibres/epoxy incorporated composites are serving better than traditional materials in order to low price, high strength, low density, sustainability, low abrasive wear and corrosion resistance. The important objectives of this experimental work are to develop the chemically treated and untreated hemp/glass fibre-reinforced composite materials and investigate the mechanical strengths like tensile strength, flexural strength and impact strengths of prepared samples as per ASTM standard. It has been observed that the chemically treated hemp/glass fibre-reinforced samples exhibited maximum flexural strengths, and these materials are recommended for automobile sectors as alternative material by replacing synthetic fibre incorporated composite materials. The interfacial behaviour, internal constituents, fibre failure mode, fibre pullout, voids and delamination of fractured area are studied by conducting morphological studies with aid of scanning electron microscopy.

Impact of variation in mechanical properties from the outer to inner zone of aluminium–copper–silicon (Al–1.5Cu–0.5Si) sand cast alloy was studied by applying three different homogenization thermodynamic states (425, 500 and 575 °C respectively) at a constant soaking time of 10 h. The effect of hardness, strength, and percentage deformation on specimens were measured at outer, middle and inner zones of the sectioned rods in both as-cast and homogenized conditions. The hardness and tensile strength of the specimens were decreased from outer zone to inner zone in both as-cast and all homogenized conditions; whereas its individual value with respect to various zones decreased with increased homogenization temperatures. It was also observed that the percentage elongation of the alloy varied inversely with the hardness and tensile strength values, and also that the hardness values varied proportional to the tensile strength.

Self-Compacting Concrete (SCC) is a special type of concrete which does not require any form of external forces to get compacted. However, it behaves similar or better to conventionally vibrated concrete when it gets hardened. The present study focuses on developing SCC with a constant powder content of 600 kg/m3 with 450 kg/m3 of cement. The remaining portion of class-F fly ash (150 kg/m3) was replaced step by step with a waste material from granite crushing industries called as quarry dust waste (QDW); which is available in abundance at crushed sand factories as a waste material resulted from the washing of crushed granite to remove very fine particles. The effects of replacement were studied at fresh and hardened states of SCC. Apart from the mechanical properties such as compressive, flexural, and split tensile strengths, the ultrasonic pulse velocity assessment was performed to ensure the integrity of test specimens. Robustness, which is the ability of SCC to perform similar way in the case of any small fluctuations in material design or properties is also studied in the present paper. The study revealed that the quarry dust waste can be incorporated in making SCC with reliable fresh and hardened properties. Additionally, the robustness of SCC with quarry dust waste is good and within acceptable limit. Moreover, the incorporation of quarry dust waste makes the concrete more sustainable.

Al–25Zn–3Cu ternary alloy was prepared using stir casting. The hardness and microstructure of as-cast and homogenized specimen were studied. From the microstructure examination results, it is clear that the as-cast dendritic structure was eliminated after homogenization. Adhesive wear test was carried out using pin-on-disc wear tester as per L9 orthogonal array. Load, velocity and sliding distance were the control parameters taken for the experiments. Then, signal-to-noise (S/N) ratio analysis was done by considering “smaller-the-better” as the goal of experiment. Using Analysis of Variance (ANOVA), the critical parameters, which affect the response were obtained and results were comparable with the S/N analysis. Also, confirmation experiments were carried out to validate the developed linear regression equation. Finally, Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX) analysis were used to detect the wear mechanisms in the worn out samples.

It is observed that articular cartilage damage is an increasing problem across the globe. Poly 2-hydroxyethyl methacrylate (pHEMA) hydrogels are promising implants for ersatz articular cartilage due to their similar tissue properties. However the major obstacle to their use as replacing articular cartilage is their poor mechanical properties. By the development of composite hydrogels with hydroxylapatite (HA) nano fillers the lack properties may overcome. The purpose of this study is to describe mechanical properties of composite hydrogels for replacement of cartilage. Therefore with different percentages of HA nano fillers the hydrogels (pHEMA/HA) were prepared by cast drying method. Mechanical properties of composite hydrogels are studied with reciprocating sliding tribo-tester and the porous nature is investigated by SEM. By the results it is observed that mechanical properties of composite hydrogels are improved by adding hydroxylapatite nano fillers.

Polyamide 6 matrix material was filled with multi -walled carbon nano tubes(MWCNT) and copper nano-particles reinforcements. The composition used for the investigation was PA6 and 0.25 wt% MWCNT with 0.2, 0.4 and 0.6 wt% copper nano-particles. Sliding wear behaviour was studied in PA6 composites. A co-rotating twin screw extruder was used to blend the materials and the specimens were prepared using injection moulding. The process parameters were Load (N), Sliding speed (m/s) and Reinforcement (%). The experiment was conducted in a Pin on Disc apparatus. Taguchi and Analysis of Variance (ANOVA) were used to analyse the influence of process parameters on wear rate. Genetic Algorithm (GA) was used to optimise the wear rate. Scanning Electron Microscope (SEM) images on worn surfaces of PA6 composites were analysed and the type of wear was observed.

In this work, a monotectoid based Zinc–Aluminium (Zn–Al) alloy was prepared using stir casting process. The Micro-Hardness of as-cast and homogenized conditions was tested and the result showed that the homogenized alloy has a slight improvement in hardness than that of the as-cast alloy. The Microstructure of the Zn–Al revealed the dendritic structure in as-cast and non-dendritic in homogenized conditions which were analysed through a scanning electron microscope (SEM). Adhesive wear is carried out by Pin-on-Disc wear tester. Wear rate of the alloy rises with applied load conducted at different speeds. The specific wear rate and the friction coefficient vary with load. The diffusion of disc material into the specimen material changes the alloy composition. It was observed through energy dispersive X-ray spectroscopy (EDX) analysis. The worn-out surfaces were studied by using SEM analysis.

In this present work, material properties (Young’s modulus and thermal conductivity) of Silicon Carbide (SiC) particle-reinforced Aluminium 1100 (Al) matrix composite have been evaluated using Representative Volume Element (RVE) technique. A three-dimensional RVE model is generated by finite element-based homogenization method for Al–SiC composite. SiC particles are randomly dispersed in various volume portions in the range of 5–20% into the matrix. Examinations are done to ponder the impact of spherical particle geometry on the material properties for all volume fractions using numerical analysis. The numerical results from the RVE approach are compared with the values obtained from the experimental results, rule of mixtures (ROM) and Halpin–Tsai equations and found that the results of RVE approach are in good agreement with the other approaches.

Friction stir processing (FSP) is a novel metal processing technique which is used for improving the material properties locally through significant grain refinement and homogenization. In FSP, processing parameter, namely, tool rotational speed plays an important role in producing a defect-free processed zone and enhancing the properties. In this work, FSP of ZE41 magnesium alloy was conducted at different tool rotational speeds (450, 650, 850, 1050, and 1250 rpm) with constant tool traversing speed of 50 mm/min. It is observed that FSP of magnesium alloy at rotational speed of 650 rpm produced superior mechanical properties as compared to other rotational speeds. This is mainly due to the optimum heat input conditions, grain refinement, and favorable distribution of second phase particles throughout the processed zone.

In research, there are many advanced methods in material science but attention should be kept on some of the areas. One such area is natural-reinforced composites. In this work, the natural fiber is bamboo fiber along with filler material. Fly ash has been taken into consideration. Extraction of fibers from jute, coir, and bamboo belongs to this category. To enhance the properties of polymers, various filler materials such as silica, fly ash, etc. are used along with natural fiber-reinforced composite. In this project, bamboo fiber hybrid composites are fabricated with polypropylene along with 10% wt concentration of fly ash. Concentration of fiber was varied up to 25% by weight, and the test specimens were prepared by injection molding. Bending properties were tested using tensometer. Bending strength and bending moment were increased with the increment of weight % of fiber in the composition.

Electroplating of nanocrystalline NiFe and NiFeW thin films were successfully carried out on the copper substrate from ammonium citrate bath at a current density of 1 mA/dm2 and controlled pH of 7 with constant bath temperature. The magnetic and corrosion properties were studied using VSM and electrochemical techniques. The results of vibrating sample magnetometer for NiFeW nanocrystalline thin films reveal its soft magnetic properties such as coercivity and saturation magnetization. From the electrochemical studies, corrosion resistance and corrosion inhibition efficiency were calculated. The electrochemical studies of all the coated films reveal that the NiFeW thin film exhibits the enhanced corrosion resistance as compared with NiFe thin film which in turn enhances the soft magnetic nature of NiFeW thin films. Thus, the electroplated NiFeW thin films can be used for Microelectromechanical System (MEMS) and Nanoelectromechanical System (NEMS) applications due to their excellent magnetic- and corrosion-resistant behaviour.

In this paper, ECAP process under room temperature conditions was carried out on EN47 spring steel and its properties were analyzed. Spring steel is corrosion resistant, and it exhibits high tensile strength and has high formability. Because of its desirable properties, it finds application in automotive and industrial suspension applications. The effects on microstructural and mechanical properties are analyzed in this study. Severe plastic deformation causes refinement of the grain structure, and it has been observed after the process. The ECAP was performed at different corner angles φ = 120° and 150° with the radius of curvature ψ = 20° through route A. The microstructural and mechanical properties were analyzed. After the pass, the values of hardness and tensile strength were measured for the different angles. After processing the sample, more columnar structures were observed in 120°, and uniformly distributed grains with equiaxed and less columnar structures were observed in 150°. This is mainly due to the occurrence of grain strengthening effect at the corner angles.

Linear Friction Welding (LFW) has been a recently developed solid-state welding process, has capabilities to efficiently join heat treatable Aluminum alloys by limiting the time at the temperature of intermetallic compound formation during the weld cycle. The transverse tensile properties of LFW joints of AA7075 Aluminum Alloy was evaluated and correlated with the microstructural characteristics of the joint. The weld joints exhibited joint efficiency of 75% with the fracture at Thermo-Mechanically Affected Zone. The XRD pattern revealed the absence of major strengthening precipitate MgZn2 in weld nugget and TMAZ of the LFW joint. The absence of strengthening precipitates and coarse grain structure led to the deterioration of the mechanical properties in the TMAZ. The fracture surfaces of the tensile specimens revealed the ductile mode of failure.

An assumption in the micromechanical analysis of polymers is that the constitutive polymeric media is nonporous. Non-porosity of media, however, is merely a simplifying assumption. In this research paper, this assumption is neglected and polymer networks with a different porosity volume fraction are studied. A random morphology description function is used to model the porosity of the network. Nonlinear finite element analyzes are conducted to perform structural analysis of porous polymer networks using an ABAQUS/CAE finite element code. The results reveal that porosity plays a significant role in the mechanical behavior of polymer networks and may increase the maximum von Mises stress drastically.

Hyperelastic materials are playing a vital role in hydraulic and pneumatic applications in the automotive industry and acts as a sealing element. Typical hyperelastic sealing elements are O-Rings, gaskets and lip seals, which are used in hydraulic and pneumatic braking systems in passenger car, light commercial and heavy commercial vehicles. If the sealing is not properly done, the efficiency and performance of the system will come down significantly. Since the hyperelastic materials are highly nonlinear, it is very difficult to predict the behaviour like sealing pressure and strain in the classical method. The behaviour of the hyperelastic material can be predicted using a numerical method called finite element analysis. The behaviour is purely based on the type of hyperelastic material model and number of material parameters. This research work will describe the material model and selection of material parameters based on the experimental study. Also, it will describe the sealing behaviour of the gasket which is used in automotive applications.

PAN-based carbon nanofibers reinforced with nanoparticles are used in various applications including energy, medical, and electronics. Many of the production methods include chemical-based approach to fabricate such fibers. Here, an attempt has been made to fabricate PAN–hematite composite fiber using physical methods. Hematite nanopowders (30–40 nm) are mixed in PAN solution. They are spun into fibers using electrospinning technique. The spun fibers are stabilized and carbonized using a tubular furnace. The fibers are then characterized for their electrical and metallurgical properties. It is found that the nanofibers have hematite reinforced in them at regular interval. The produced PAN-Hematite composite fiber yielded desired electrical and metallurgical properties.

The marine aluminum alloy 12 mm thick plates are joined using Tungsten Inert Gas welding technique. The mechanical properties and microstructural features of Tungsten Inert Gas welded joints of the Aluminum Alloy 5083-F with two Al–Si filler rods are investigated. Weldments processed by Al–Si filler rods, such as ER4043 and ER4047 are mechanically softer than the base material AA5083 in F condition. The welded joint tensile strength of ER4043 filler rod-welded joints is 33% higher than that of the ER4047 filler rod-welded joints tensile strength.