Ab initio calculations on elastic properties in L1(2) structure Al3X and X3Al-type (X= transition or main group metal) intermetallic compounds

作者：Tian, T; Wang, X F^*; Li, W

来源：Solid State Communications, 2013, 156: 69-75.

DOI：10.1016/j.ssc.2012.10.021

• L1(2) intermetallic compounds
• Elastic constants
• Extreme Poisson's ratio
• Electronic structure

As high-temperature structural materials, L1(2) intermetallic compounds have attracted the strong interest from both fundamental and industrial aspects. Understanding of elastic property is a basis for the complete investigations of mechanical behavior of L1(2) alloys. In an effort to explore the electronic origin of elastic properties of L1(2) intermetallics, we have performed a systematic study on elastic constants for single crystals, and Young's modulus, shear modulus, bulk modulus and Poisson's ratio for poly-crystals of 22 known Al3X and X3Al-type (X= transition or main group metal) intermetallics using the ab initio calculations. Based on the calculations of elastic constants and extreme (both positive and negative) Poisson's ratios, we found a pronounced correlation between the extreme Poisson's ratio and the elastic anisotropy, i.e., approximate 40% of the investigated L1(2) intermetallics exhibit intrinsic auxetic behavior. Furthermore, based on the distribution of bonding charge densities, we revealed that the ductility and extreme Poisson's ratios were attributable to the directionality of bonds of these alloys. Our findings provide a new method to predict mechanical behavior of intermetallics.

• 出版日期2013-3
• 单位湘潭大学