Ti-4. 5Al-3V-2Mo-2Fe 合金置氢工艺及 0. 1wt. %低氢含量超塑变形研究

The average grain size of the rolled Ti-4. 5Al-3V-2Mo-2Fe dual-phase titanium alloy sheet is less than 3 μm. The hydrogen absorption characteristics of the alloy at different temperatures, holding time and hydrogen pressures were studied by thermohydrogen processing. Based on this, a mathematical model for preparing standard hydrogen content was developed. By detection means of electron backscatter diffraction (EBSD) and time of flight secondary ion mass spectrometry (TOF-SIMS), it is found that the hydrogen element in the 0. 1 wt. % sample is mainly concentrated in the surface layer. The elongation of the original alloy at the optimum forming temperature of 760 ℃ is 1827%. The optimum superplastic forming temperature is decreased by 20 ℃ when the elongation of 0. 1wt. % hydrogenated alloy is 1510%. The constitutive models of the original and hydrogenated alloys were established by Backoften equation, and the finite element calculation model of superplastic bulging of barrel parts was introduced. By comparison, it is found that the bulging depth of the hydrogenated alloy is smaller than that of the original material and more prone to cracking risk.