Elastic properties, tensile strength, damage tolerance, electronic and thermal properties of TM3AlC2 (TM = Ti, Zr and Hf) MAX phases: A first-principles study

Abstract

This study explored the phase stability of TM3AlC2 (TM = Ti, Zr and Hf) and related ternary competing MAX phases, as well as the elastic properties, ideal tensile strength, electronic and thermal properties based on first-principles calculations. TM3AlC2 (TM = Ti, Zr and Hf) phases are thermodynamically and dynamically stable. In addition, Ti3AlC2, Zr3AlC2 and Hf3AlC2 are elastic anisotropic, and have larger ideal tensile strength along the close packed direction. From the obtained Young's modulus, Ti3AlC2, Zr3AlC2 and Hf3AlC2 are potentially thermal shock resistant materials. Besides, Zr3AlC2 has the best damage tolerance and resistance to crack expansion according to the calculated Pugh's ratio and KIC of TM3AlC2 (TM = Ti, Zr and Hf). TM3AlC2 (TM = Ti, Zr and Hf) are potentially thermally conductive materials at ambient temperature and potential high-temperature thermal barrier coating materials. Finally, the variation of heat capacity versus temperature was predicted.