Exploration of D022-Type Al3TM(TM = Sc, Ti, V, Zr, Nb, Hf, Ta): Elastic Anisotropy, Electronic Structures, Work Function and Experimental Design.

Guowei Zhang,Yizheng Fu,Mingjie Wang,Hong Xu,Fenger Sun,Heping Liu,Xiaoyan Ren

doi:10.3390/ma14092206

Guowei Zhang, Yizheng Fu + Show 5 more

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https://doi.org/10.3390/ma14092206

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Abstract

The structural properties, elastic anisotropy, electronic structures and work function of D022-type Al3TM (TM = Sc, Ti, V, Y, Zr, Nb, La, Hf, Ta) are studied using the first-principles calculations. The results indicate that the obtained formation enthalpy and cohesive energy of these compounds are in accordance with the other calculated values. It is found that the Al3Zr is the most thermodynamic stable compound. The mechanical property indexes, such as elastic constants, bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, and Vickers hardness are systematically explored. Moreover, the calculated universal anisotropic index, percent anisotropy and shear anisotropic factors of D022-type Al3TM are analyzed carefully. It demonstrates that the shear modulus anisotropy of Al3La is the strongest, while that of Al3Ta is the weakest. In particular, the density of states at Fermi level is not zero, suggesting that these phases have metal properties and electrical conductivity. More importantly, the mechanisms of correlation between hardness and Young’s modulus are further explained by the work function. Finally, the experimental design proves that D022-Al3Ta has an excellent strengthening effect.

Highlights

With the increasing demand of aerospace and automotive industry for structural material properties, aluminum rich compounds containing transition metal (TM, i.e., Sc, Ti, V, Y, Zr, Nb, La, Hf, Ta) elements have attracted extensive attention [1,2,3]
Al3 TM (TM = Sc, Ti, V, Y, Zr, Nb, La, Hf, Ta), the first-principle calculations based on Materials 2021, 14, 2206 density functional theory are implemented in the CASTEP
The results show that the value of formation enthalpy of these D022 -type compounds is −0.366, −0.396, −0.283

Summary

Introduction

With the increasing demand of aerospace and automotive industry for structural material properties, aluminum rich compounds containing transition metal (TM, i.e., Sc, Ti, V, Y, Zr, Nb, La, Hf, Ta) elements have attracted extensive attention [1,2,3]. Trialuminides (Al3 TM) are the most potential candidate compounds, mainly because it can meet a variety of advantages, such as a high melting point, good thermal conductivity, low temperature damage resistance, strong creep resistance, and high specific strength. Most of these intermetallics have different crystal structures of L12 , D019 , D022 , or D023 [4,5,6,7,8,9,10,11]. The L12 structure has better ductility due to its higher symmetry and more slip systems. One of the critical challenges is to explore the internal mechanism of D022 -type trialuminides

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