A novel simplified model for measuring the twinnability of face-centred-cubic metals

ABSTRACT

Twinnability is a unique property describing the ease with which a metal plastically deforms by twinning relative to dislocation-mediated slip. Based on first-principles calculations, a simple and effective model, including two calculational supercells with three typical generalised stacking fault structures, is proposed to measure the twinnability of face-centred-cubic metals. Here, we investigated the interaction of alloying atoms with generalised stacking faults and their impact on the twinnability of aluminium alloys. It is found that the twin propensity of Al alloy increases with the increasing concentration of Sc and Ti, and a small increase with Y, while the addition of Sr, Zn, Sn and Ga exhibits opposite trends. It is predicted that twins will remain stable once they were formed in Al–Sc alloys on account of the small extrinsic stacking fault energy.

KEYWORDS:

• Twinnability
• Al alloys
• solute atoms
• stacking faults
• first-principles calculations

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work is supported by the National Natural Science Foundation of China (Nos. 51701243), the Hunan Provincial Natural Science Foundation of China (No. 2019JJ40544) and the PhD Research Startup Foundation of Central South University of Forestry and Technology (No. 2017YJ020), as well as by the Xiangqing Super Computational Platform (No. gg07026).