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钛合金的超塑成形技术在工业领域已经得到广泛的应用,但其成形温度高,成形速率低的问题大大限制了该技术的发展。向钛合金中添加适量的氢,可有效改善合金的热加工性能。以Ti-55高温钛合金为对象,通过金相观察、高温拉伸试验等方法,研究了置氢对合金微观组织和超塑变形行为影响,得出了氢含量、变形温度和初始应变速率对其伸长率和峰值应力的影响规律。研究发现,置氢0.1%之后,合金在825℃变形时伸长率提高了95.5%,峰值应力降低了37.8%;置氢0.1%使得Ti-55的最佳超塑成形温度降低了约125℃;置氢后合金对于变形温度和应变速率的变化更加敏感,且最佳超塑性的温度和应变速率范围变窄。
The superplastic forming technology of titanium alloy has been widely used in the field of industry, but the problem of high forming temperature and low forming speed greatly limits the development of the technology. Adding a suitable amount of hydrogen to the titanium alloy can effectively improve the hot workability of the alloy. The effects of hydrogen on the microstructure and superplastic deformation behavior of Ti-55 high temperature titanium alloy were studied by metallographic observation and high temperature tensile test. The effects of hydrogen content, deformation temperature and initial strain rate Its elongation and peak stress of the law. The results show that the elongation at 95% elongation and the peak stress decrease about 37.8% at 825 ℃ and 0.1% respectively after the hydrogen is set at 0.1%. The optimal superplastic forming temperature of Ti-55 is reduced by about 125 ℃ ; After hydrogen is set, the alloy is more sensitive to the change of deformation temperature and strain rate, and the range of temperature and strain rate of optimum superplasticity becomes narrower.