Competition between prismatic and basal slip in hexagonal titanium–aluminum alloys with short-range order

Abstract

Plasticity of hexagonal titanium–aluminum alloys depends on the solute concentration and the order state of Al atoms. Development of short-range order (SRO) modifies Al strengthening and impacts the competition between prismatic and basal slip modes. Using ab initio calculations, we study the interaction of a screw dislocation with isolated Al atoms and Al pairs in an hcp Ti existing in short-range ordered Ti–Al alloys. Calculated activation energies reveal pronounced hardening caused by Al addition for both slip systems, which become competitive. This hardening is enhanced for Al pairs, resulting in a reduced plastic anisotropy of Ti–Al alloys with SRO.

GRAPHICAL ABSTRACT

IMPACT STATEMENT

Short-range ordering is shown to impact plasticity in ahexagonal Ti–Al solid solution through ab initio modeling of dislocation interaction withsolute and pair of solute atoms.

Keywords:

• Titanium–aluminum alloys
• ordering
• plasticity
• dislocations

Acknowledgments

The authors acknowledge the PL-GRID infrastructure, which provided the computational resources—the Promethus and Tryton supercomputers.

Data availability

All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. Any additional details are available from the corresponding author upon reasonable request.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by the Polish National Science Centre under grant no. 2019/35/D/ST5/02379 (UMO-2019/35/D/ST5/02379) and Polish Ministry of Education within the grant no. MEiN/2022/DPI/1064.