中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 35 No. 10 October 2025 |
（1. School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023, China;
2. Provincial and Ministerial Co-construction of Collaborative Innovation Center for Non-ferrous Metal New Materials and Advanced Processing Technology, Luoyang 471023, China;
3. School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China;
4. Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China）
Abstract:A unique discontinuous lamellar microstructure of titanium alloys consisting of lamellar colonies at prior β-Ti grain boundaries and internal interwoven α-laths is prepared by a TiH2-based powder metallurgy method. The α-variants get various crystallographic orientations and become discontinuous during vacuum annealing at 700 °C. Remarkably, nanoscale phase δ-TiH compound layers are generated between α-laths and β-strips, so that dislocations are piled up at the α/δ/β interfaces during tensile deformation. This leads to dislocation slips being confined to individual α-laths, with different áa？ slips and particularly pyramidal ác+a？ slips being activated. The efficiency of wavy slip is promoted and the work hardening rate is enhanced. Finally, the combined effect of dispersed micro-shear bands and lath distortions is considered contributive for alleviating the stress concentration at grain boundaries, resulting in a high-promising synergy of enhanced ultimate tensile strength of 1080 MPa and good elongation to fracture of 13.6%.
Key words: TiH2-based powder metallurgy; discontinuous lamellar microstructure; interfacial δ-TiH phase; tensile properties; deformation behavior
