Effect of high pressure on the crystal structures of lanthanide trialuminides

doi:10.1016/0022-5088(75)90076-4

Journal of the Less Common Metals

Volume 40, Issue 3, May 1975, Pages 313-328

https://doi.org/10.1016/0022-5088(75)90076-4 Get rights and content

Abstract

The effect of high pressure on the crystal structures of LnAl₃ (Ln = Lanthanide) compounds has been determined by exposing LnAl₃ compounds or stoichiometric mixtures of the elements, to high-pressure and high-temperature conditions in a tetrahedral-anvil apparatus. In accordance with considerations of relative compressibilities, the application of high pressure tends to make the lower-atomic-weight lanthanides behave more like those of higher atomic weight. Thus, high-pressure-induced polymorphic changes were in the direction of structures with increased cubic character. Polymorphs or compounds first reported in this paper are BaPb₃-type GdAl₃, HoAl₃-type TbAl₃ and Cu₃Au-type LuAl₃. The first two are hexagonal with lattice parameters $α = 6.231, c = 21.173 A ̊, and α = 6.095, c = 35.96 A ̊$ , respectively. The third compound is cubic, with lattice parameter $α = 4.186 A ̊$ .

References (31)

W.B Pearson
J. Less-Common Metals
(1967)
K.A Gschneidner et al.
Mater. Res. Bull.
(1968)
K.H.J Buschow
J. Less-Common Metals
(1965)
O.J.C Runnalls et al.
J. Less-Common Metals
(1967)
T.I Jones et al.
J. Less-Common Metals
(1963)
J.H.N van Vucht et al.
J. Less-Common Metals
(1965)
J.H.N van Vucht et al.
Philips Res. Repts.
(1964)
K.H.J Buschow et al.
K.H.J Bushow et al.
Philips Res. Repts.
(1967)
E.E Havinga et al.
Philips Res. Repts.
(1969)

E.E Havinga et al.

Philips Res. Repts.

(1970)

K.A Gschneidner

Philips Res. Repts.

(1970)

H.T Hall

Rev. Sci. Instr.

(1958)

H.T Hall

Rev. Sci. Instr.

(1962)

Cited by (73)

Experimental investigation and thermodynamic modeling of the Al–Dy and Ni–Al−Dy systems
2024, Calphad: Computer Coupling of Phase Diagrams and Thermochemistry
The partial phase equilibria of the Ni–Al−Dy ternary system have been systematically investigated via experimental analyses and thermodynamic modeling. Using the equilibrated alloy method, the 1150 °C and partial 800 °C isothermal sections of the Ni–Al−Dy ternary system and related Al–Dy binary system were constructed based on scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. Twelve three-phase regions were confirmed and four three-phase equilibria regions were speculated at 1150 °C, eight three-phase regions were determined at 800 °C, and five kinds of primary solidification regions, DyAl₂, τ7, τ5, NiAl and Ni₂Al₃ were observed. A new ternary compound τ12 was discovered, which was stable at 800 °C and disappeared at 1150 °C, the τ1 phase was not stable at 800 and 1150 °C isothermal sections; the ternary compound τ11 was confirmed to be stable at 800 °C. In addition, the primary solidification phases were also identified, and five different primary solidification phases were found. Based on the experimental results available in this study and the literature, the thermodynamic modeling of the Ni–Al–Dy ternary system was obtained using the CALPHAD method. A set of self-consistent thermodynamic parameters for the Ni–Al–Dy ternary system was first obtained with a satisfactory agreement between the experimental and calculated results.
Degraded creep resistance induced by static precipitation strengthening in high-pressure die casting Mg–Al–Sm alloy
2024, Journal of Materials Science and Technology
Relationship between precipitation strengthening and creep resistance improvement has been an important topic for the widespread applications of magnesium alloys. Generally, static precipitation strengthening through thermal stable precipitates would generate satisfactory creep resistance. However, an opposite example is presented in this work and we propose that the size of precipitates plays a crucial role in controlling the operative creep mechanisms. In addition, the precipitate components along with their crystal structures in the crept Mg–4Al–3Sm–0.4Mn samples with/without pre-aging were thoroughly studied using Cs aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). Previous aging generates a large density of fine precipitates (< ∼5 nm) homogeneously distributing in Mg matrix and exhibiting satisfactory strengthening effect. However, the number density of precipitate strings consisting of several or even dozens of relatively coarse precipitates (∼10 nm) was significantly decreased at the same time. As revealed in this work, the relatively coarse particles in Mg matrix are much more efficient than the fine precipitates in promoting dislocation climb. Therefore, the rate-controlling mechanisms are transferred from dislocation climb to dislocation slip after previous aging, thus leading to degradation of creep resistance. Moreover, there are mainly five types of precipitates/clusters, namely β″-(Al, Mg)₃Sm, Al₅Sm₃, ordered Al–Sm cluster, ordered Al–Mn cluster and ordered/unordered AlMnSm clusters. The crystal structures of the former two precipitates were discussed and the formation mechanisms of the precipitates/clusters were revealed.
First-principles study on the effects of Er/Hf ratio on the properties of L1<inf>2</inf>-Al<inf>3</inf>(Er,Hf)
2023, Materials Today Communications
L1₂-structured tri-aluminides in additively manufactured (AM) Al alloys refine α-Al grains while playing a significant role in precipitation strengthening. To precipitate the tri-aluminide dispersoids with an improved nucleation efficiency and coarsening resistance in AM Al alloys, the joint addition of Er and Hf into Al is proposed to form ternary L1₂-Al₃(Er,Hf) precipitates. The work applies the first-principles method of projected augmented wave (PAW) under the framework of density functional theory (DFT), to calculate the lattice constant, formation energy, binding energy, bulk modulus, and density of states of L1₂-Al₃(Er_x,Hf_1-x) (x = 0, 0.25, 0.5, 0.75, 1). The effects of Er/Hf ratios on certain key properties and features of the L1₂-Al₃(Er,Hf) compounds and an Al alloy that contains the compounds are discussed.
Magnetic, thermal, and magnetocaloric properties of the holmium trialuminide HoAl<inf>3</inf> with polytypic phases
2022, Journal of Magnetism and Magnetic Materials
We investigate the magnetic, thermal, and magnetocaloric properties of the intermetallic HoAl₃ compounds with two different crystal structures. The room-temperature equilibrium trigonal phase HoAl₃ undergoes an antiferromagnetic (AFM) transition at the Néel temperature $T_{N}^{tri} =$ 9.8 K. The AFM order of the compound is strong against the magnetic field, so that inverse magnetocaloric effect (MCE) is found even under a magnetic field change of 0–50 kOe. The high-pressure cubic phase HoAl₃, prepared by a rapid-solidification process, is antiferromagnetically ordered below $T_{N}^{cub} =$ 15 K. Magnetic and specific heat measurements reveal that this long-range AFM state becomes unstable as the temperature drops and then is replaced by a magnetic glassy state below a spin freezing temperature $T_{f} =$ 11 K. The successive changes in magnetic state result in complicated temperature and field dependence of the MCE at low temperatures.
High-throughput first-principles study of physical properties of L1<inf>2</inf>-Al<inf>3</inf>M particles
2022, Materials Today Communications
Citation Excerpt :
As the format of the output file in VASP calculation is not in consistence with the input file of BoltzTraP, we used the VASPKIT code [83] for converting. The calculated equilibrium lattice constants (ELCs) a0 and formation enthalpies of different compounds at 0 K and 0 GPa with previous theoretical data and available experimental results [17,18,45,90–104] are shown in Table 1 and Fig. 1, and a good agreement can be clearly seen, indicating that the present calculations are accurate and reliable. All the compounds have larger ELCs than Al, except for Al3Li, Al3Fe and Al3Cu.
The mechanical, thermal and electrical properties of L1₂-Al₃M (M=RE (Sc, Y, La-Lu), Li, Na, Ca, Fe and Cu) in Al based alloys at various temperatures and pressures have been investigated by combining first-principles calculations with quasi-harmonic approximation. The results show that the lattice constant, lattice mismatch, and formation enthalpy of L1₂-Al₃M compounds are closely related to the radius of M atoms and electrons transferred from M to Al. Al₃La presents the largest strengthening effect, while Al₃Sc shows the most stability. The elastic parameters of Al₃M compounds increased linearly with the increase of pressure, but slightly decreased with temperature, while Poissson’s ratio ν and Pugh’s ratio B/G maintain the characteristic of brittleness. The calculated electrical conductivity of L1₂-Al₃M is nearly unchanged, whereas the thermal conductivity is increased with the increase of temperature. The lower values of Seebeck coefficient and merit ZT clearly indicate that these L1₂-Al₃M compounds show metallic bond feature and are not suitable for thermoelectric devices. Finally, the thermal conductivities (TCs) of Al alloys containing L1₂-Al₃M as functional of compound concentration and temperature are obtained based on the Maxwell model. These results are helpful for designing high performance heat-resistance Al alloys.
Magnetocaloric particles of the Laves phase compound HoAl<inf>2</inf> prepared by electrode induction melting gas atomization
2022, Journal of Magnetism and Magnetic Materials
Processing magnetocaloric materials into magnetic refrigerant particles is an essential issue in developing high-performance magnetic refrigerators. Here, we succeed in stably producing magnetocaloric particles of the promising material HoAl₂ by a newly devised method based on electrode induction melting gas atomization process. The particle size range is on the order of submillimeters, which is suitable for practical refrigeration systems. The resulting particles with less contamination have good morphological, magnetic, and magnetocaloric properties: (i) almost spherical shapes with few internal pores, (ii) a sharp ferromagnetic transition around 30 K, and (iii) a large magnetocaloric effect comparable to the bulk counterpart. These features suggest the HoAl₂ gas-atomized particles have the potential of use as a magnetic refrigerant. The presented method can be applied not only to HoAl₂ but also to other brittle magnetocaloric materials with high melting points, facilitating the production of various magnetic refrigerants needed to develop magnetic refrigerators for hydrogen liquefaction.

View all citing articles on Scopus

View full text

Effect of high pressure on the crystal structures of lanthanide trialuminides

Abstract

J. Less-Common Metals

Mater. Res. Bull.

J. Less-Common Metals

J. Less-Common Metals

J. Less-Common Metals

J. Less-Common Metals

Philips Res. Repts.

Philips Res. Repts.

Philips Res. Repts.

Philips Res. Repts.

Philips Res. Repts.

Rev. Sci. Instr.

Rev. Sci. Instr.