Characterization of Submicron-Grained Ti-6Al-4V Sheets with Enhanced Superplastic Properties

摘要

The microstructure, texture, room temperature and Superplastic properties of the Ti-64 sheets with submicrocrystalline (SMC) structure were investigated. For evaluate the Superplastic performance of submicron-grained sheets the tensile tests were carried out in the temperature range of 600-800℃. Submicron-grained sheets possessed a strong basal texture and isotropic mechanical properties in the rolling plane, higher yield strength and ultimate tensile strength than that of commercial sheet. At exceptionally low temperature range of 650-750℃ the submicron-grained sheets demonstrated enhanced Superplastic properties, which are defined as an initial flow stress of 15-30 MPa and about 1000% elongation at the strain rates of 3 x 10~(-4) - 7 x 10~(-4)/ and temperature of 750℃. At the same time, the flow stress increased considerably due to grain growth during deformation at low strain rates and deformation temperatures above 700℃.