High Throughput First-Principles Investigate the Stability, Mechanical and Thermo-Dynamic Properties of Alxtmy Intermetallics in Aluminum Alloys

Abstract

The mechanical, thermal and electrical properties of 8 types of common AlxTMy (TM=Sc-Zn, Y-Cd, Hf-Hg) intermetallics in Al based alloys at various temperatures and pressures have been investigated by combining first-principles calculations with the Debye model. The result clearly shows that the moduli of most AlxTMy intermetallics are increased as compared to Al. The elements with more electrons transferred favored the formation of stable structures, and the values of all mechanical parameters are closely related to the characteristics of valence electron. The Helmholtz free energy F of Al bulk and stable AlxTMy intermetallics is decreased with increasing temperature, while the entropy S, heat capacity CV and coefficient of expansion aT show the opposite trends. And the smaller F presents the lower aT; that is the compounds constitute of elements of IB ~ IVB have larger F and aT, while the compounds with VB ~ VIIB have smaller F and aT. This work is helpful for the investigation of the high-performance of Al-based alloys.

Keywords: First-principles calculations, AlxTMy intermetallics, Mechanical properties, Quasi-harmonic approximation