Newly found phase transition and mechanical stability of AuAl2: A first-principles study

• Determination of high-pressure orthorhombic phase for AuAl2.
• Analyze mechanical stability under tensile strains based on electronic structure.
• Mechanism of different tensile strengths for AuAl2, Au and Al metals.

Investigations of the structural stabilities and mechanical stability of AuAl2 were conducted by using first-principles pseudopotential method. A structural phase transition was predicted at 17.2 GPa, and the high-pressure phase is identified to be PbCl2-type structure, which was not classified by experimental studies. The stress–strain relationships under tensile deformations of AuAl2 are presented and compared with Au and Al metals, respectively. Moreover, the low tensile deformation resistance is interpreted by the electronic structure analysis.