Superplastic deformation behavior of hot isostatic pressed Ti-45Al-7Nb-0.3W hot-rolled alloy sheet
PENG Yuqin1, LI Yingxin2, LIANG Xiaopeng1, LI Huizhong1, CHE Yixuan1, GUO Xinming1
1. School of Materials Science and Engineering, Central South University, Changsha 410083, China; 2. Zhuzhou Ruideer Metallurgy Equipment Manufacturing Co., Ltd., Zhuzhou 412000, China
Abstract：The hot isostatic pressed (HIP) Ti-45Al-7Nb-0.3W alloy sheet prepared by hot-rolled at 1 270 ℃, and the microstructure of the alloy sheet was investigated by scanning electron microscopy (SEM). High-temperature tensile experiments at 950 ℃ with an initial strain rate of 1×10-4 s-1 were performed. According to the tensile stress-strain curve and tensile properties, as well as the microstructure evolution and tensile fracture morphology after tensile fracture, the superplastic deformation (SPF) behavior of the alloy sheet with rolling deformation was studied. The results show that after rolling, the microstructure of as-HIPed alloy sheet changes from near-γ microstructure to duplex microstructure. And the average grain size of the sheet decreases and the elongation increases with the increase of rolling reductions. When the rolling reduction is 61%, the average grain size of the hot-rolled sheet is the smallest (9.8 μm), the elongation of the sheet is the largest (367.5%), and the tensile strength is 131 MPa. Continue to increase the rolling deformation, the grain size of the sheet grows, and the elongation decreases. During the SPF, the α2/γ lamellar colonies rotate and decompose, and a large number of dynamically recrystallized (DRX) grains are generated around them. The superplastic mechanism of the plates is grain boundary slip (GBS) and DRX.
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2022, Vol. 27 
