Simultaneously enhanced strength and ductility in a metastable β-Ti alloy by stress-induced hierarchical twin structure

• DOI: 10.1016/j.scriptamat.2020.03.039
• Publication Date: 2020-04-05T09:07:46Z
• Authors: Lei Ren; Wenlong Xiao; Damon Kent; Min Wan; Chaoli Ma; Lian Zhou
• Keywords: 3104 Condensed Matter Physics; 2500 Materials Science; microstructure; 2210 Mechanical Engineering; 2506 Metals and Alloys; 02 engineering and technology; hierarchical twin structure; Condensed Matter Physics; ductility; 2211 Mechanics of Materials; metastable β-Ti alloy; 0205 materials engineering; FoR 0913 (Mechanical Engineering); 669; FoR 0204 (Condensed Matter Physics); General Materials Science; strength; FoR 0912 (Materials Engineering)

Abstract A novel metastable β-Ti alloy Ti-4Mo-3Cr-1Fe with high strength and high ductility was developed through controlling the alloyʼs stability and deformation mechanisms. The microstructure consists of randomly oriented β-grains containing an even distribution of athermal ω precipitates. Under tensile loading, the alloy exhibits unprecedented and comprehensive mechanical properties including a high yield strength of 870 MPa, excellent total elongation of 41% and an ultrahigh strain hardening rate of 2.5 GPa. Based on investigations of deformation microstructures, the superior mechanical properties are attributed to stress-induced formation of a complex nano-scale hierarchical twin structure which is promoted by reversion of ω precipitates.