Tensile deformation behavior of coarse-grained Ti-55 titanium alloy with different hydrogen additions
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Tensile deformation behavior of coarse-grained Ti-55 titanium alloy with different hydrogen additions Xi-Feng Li, Fang-Fei Xu, Lan Hu, Fu-Hui Zhu, Jun Chen*
Received: 21 July 2019 / Revised: 28 September 2019 / Accepted: 17 July 2020 Ó The Nonferrous Metals Society of China and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The effect of hydrogen addition on the deformation behavior of coarse-grained Ti-55 alloys (* 20 lm) was studied by uniaxial tension tests at high temperature. The elongation of hydrogenated Ti-55 titanium alloy firstly increases and then decreases with hydrogen content increasing at 875 °C. The highest elongation of 243.8% is obtained in the hydrogenated alloy with 0.1 wt% H, and the peak stress reaches a minimum value of 29.0 MPa in the hydrogenated alloy with 0.3 wt% H. Compared with that of the unhydrogenated alloy, the elongation of the hydrogenated alloy with 0.1 wt% H increases by 41.3% and its peak stress decreases by 40.6% at 875 °C. Hydrogen addition can promote the transformation of b phase and the dislocation movement. Appropriate hydrogen content can evidently improve the deformation properties of coarse-grained Ti-55 titanium alloy. Keywords Coarse-grained Ti-55 titanium alloy; Hydrogen addition; Plastic deformation
1 Introduction Hydrogen can be readily absorbed and removed in titanium alloys due to high affinity of each other. Thermohydrogen processing is an attractive approach by using hydrogen as a X.-F. Li, F.-F. Xu, F.-H. Zhu, J. Chen* Department of Plasticity Technology, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, China e-mail: [email protected] L. Hu Shanghai Aerospace Equipments Manufacturer Co., Ltd., Shanghai 200245, China
temporary element in titanium alloys to modify the microstructure and mechanical properties. As a b phase stabilized element, hydrogen contributes to the increase in b phase content, which improves the workability and decreases forming temperature of titanium alloys [1–6]. In fact, the hydrogen-induced low-temperature superplasticity for fine-grained titanium alloys has been reported in a few studies. Zhang and Zhao [7] obtained the optimum superplasticity of fine-grained Ti-6Al-4V alloy (the mean grain sizes of a and b phases are 6.84 and 6.77 lm, respectively) at 800 °C for the specimens containing 0.13 wt%– 0.32 wt% H. Murzinova et al. [8] reported that the submicrocrystalline VT6 alloy (Ti-6.0Al-4.5V) doped with 0.4 wt% H was superplastic in the temperature range of 500–650 °C and the optimum rate of superplastic deformation was higher by an order of magnitude than that of the basic alloy. Zhang et al. [9] studied the effect of hydrogen on the superplasticity of Ti600 titanium alloy. The results show that the optimum deformation temperature of Ti600 alloy can be decreased by about 80 °C and the optimum strain rate can be increased by at least one order. In addition, the superplasticity of coarse-grained titanium alloy by hydrogen addition has
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