Achieving superior grain refinement and mechanical properties in vanadium through high-pressure torsion.and subsequent short-term annealing

作者：Huang Yi; Lemang Mathilde; Zhang Nian Xian; Pereira Pedro Henrique R; Langdon Terence G

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2016, 655: 60-69.

DOI：10.1016/j.msea.2015.12.086

• Hardness
• High-pressure torsion
• Short-term annealing
• Ultrafine-grained materials
• Vanadium

Commercial purity vanadium with an initial grain size of similar to 27 mu m and a Vickers microhardness of Hv approximate to 85 was processed by high-pressure torsion (HPT) under a pressure of 6.0 GPa at room temperature through 1/2 to 10 turns. After processing through 10 turns, some samples were immediately subjected to a short-term annealing (15 min) at different temperatures from 773 to 1173 K. The microstructures developed in HPT and in HPT plus post-HPT annealing were characterized by electron backscatter diffraction (EBSD). Processing by HPT for 10 turns gave a refined grain size of similar to 410 nm and an increased hardness of Hv approximate to 240. Post-HPT annealing demonstrated that the ultrafine grained vanadium has good thermal stability up to at least 873 K. Tensile testing at room temperature gave an ultimate tensile strength of similar to 920 MPa after 10 turns of HPT with an elongation of similar to 29%. These results show HPT processing produces superior mechanical properties in vanadium by comparison with processing by ECAP or ECAP plus cryorolling.

• 出版日期2016-2-8