First-Principles Investigations of the Structural, Anisotropic Mechanical, Thermodynamic and Electronic Properties of the AlNi2Ti Compound

Shuli Tang,Zhiwei Liu,Xiangyi Ren,Yefei Li,Qiaoling Zheng,Yimin Gao

doi:10.3390/cryst8020093

Abstract

In this paper, the electronic, mechanical and thermodynamic properties of AlNi2Ti are studied by first-principles calculations in order to reveal the influence of AlNi2Ti as an interfacial phase on ZTA (zirconia toughened alumina)/Fe. The results show that AlNi2Ti has relatively high mechanical properties, which will benefit the impact or wear resistance of the ZTA/Fe composite. The values of bulk, shear and Young’s modulus are 164.2, 63.2 and 168.1 GPa respectively, and the hardness of AlNi2Ti (4.4 GPa) is comparable to common ferrous materials. The intrinsic ductile nature and strong metallic bonding character of AlNi2Ti are confirmed by B/G and Poisson’s ratio. AlNi2Ti shows isotropy bulk modulus and anisotropic elasticity in different crystallographic directions. At room temperature, the linear thermal expansion coefficient (LTEC) of AlNi2Ti estimated by quasi-harmonic approximation (QHA) based on Debye model is 10.6 × 10−6 K−1, close to LTECs of zirconia toughened alumina and iron. Therefore, the thermal matching of ZTA/Fe composite with AlNi2Ti interfacial phase can be improved. Other thermodynamic properties including Debye temperature, sound velocity, thermal conductivity and heat capacity, as well as electronic properties, are also calculated.

Highlights

AlNi2 Ti is one of the Heusler compounds first identified by Heusler in 1903 [1]
The Heusler compounds are a group of ternary intermetallic alloys formed at the stoichiometric composition X2 YZ
AlNi2 Ti precipitate phase has been observed in microstructures of Al-doped Ni-Ti shape memory alloys that have huge potential to be applied as functional material in many areas such as clinical medicine, biotechnology, automation, energy engineering, electronics industry, aeronautics and astronautics, owing to their pseudoelasticity, superplasticity and shape memory properties [27,28,29,30,31,32]

Summary

Introduction

The Heusler compounds are a group of ternary intermetallic alloys formed at the stoichiometric composition X2 YZ (generally, X and Y are transition metals and Z is a b-subgroup element), with the doubly ordered L21 structure based on the ordered B2 [2]. They have been widely reported to have excellent ferromagnetic, paramagnetic, mechanical and thermoelectric properties [3,4]. AlNi2 Ti precipitate phase has been observed in microstructures of Al-doped Ni-Ti shape memory alloys that have huge potential to be applied as functional material in many areas such as clinical medicine, biotechnology, automation, energy engineering, electronics industry, aeronautics and astronautics, owing to their pseudoelasticity, superplasticity and shape memory properties [27,28,29,30,31,32]

Methods

Results

Conclusion