Enhanced mechanical properties of Ti-5Al-5Mo-5V-3Cr-1Zr by bimodal lamellar precipitate microstructures via two-step aging

• DOI: 10.1016/j.msea.2021.142117
• Publication Date: 2021-09-27T19:55:57Z
• Authors: Yalong Wang; Mengyuan Hao; Dian Li; Pei Li; Qianglong Liang; Dong Wang; Yufeng Zheng; Qiaoyan Sun; Yunzhi Wang
• Keywords: Ductility (Earth science); Spinodal decomposition; Elongation

The formation of ultra-fine α precipitates in β-titanium alloys can significantly improve strength but may lead to rupture and low ductility. Here, we propose a simple two-step aging heat treatment design bimodal microstructure with distinctively different populations fine-scale coarse Ti-5Al-5Mo-5V-3Cr-1Zr (Ti-55531, wt. %) by involving two transformation mechanisms, i.e., classical nucleation growth, pseudo-spinodal decomposition. Such multi-scale exhibits synergistic combination yield (∼1.1 GPa) ductility (∼19.5% elongation). TEM characterization shows that the appearance deformation twins contribute increased ductility, higher be attributed dislocation tangles precipitates. Our work provides new strategy overcome strength-ductility trade-off designing heterogeneous microstructure.