形变热处理对TC9钛合金组织及拉伸性能的影响

Effect of thermomechanical treatment on microstructure and tensile properties of TC9 titanium alloy

研究了锻造变形量、固溶时效温度等对TC9钛合金锻棒组织和力学性能的影响。结果表明:锻造变形能细化TC9钛合金的β晶粒尺寸、弱化或抑制α微织构的形成,并消除连续的晶界α相;随着锻造变形量从67%增加至92%,原始β晶粒和α微织构平均尺寸分别从420和80μm降低至280和20μm;随固溶温度的升高,板条α相球化成短棒状、等轴α相,随后转变为β相,α相含量逐渐减少和尺寸逐渐减小,β相则表现出相反趋势;随时效温度的升高,板条α相球化的同时β基体上析出针状次生α相。固溶时效处理后,由于板条α相再结晶及β基体上纳米级次生α相弥散析出,合金的屈服强度得到显著提升。

Effect of forging deformation and solution and aging temperature on microstructure and mechanical properties of TC9 titanium alloy forgings was studied.The results show that the forging deformation can refine theβgrain size of the TC9 titanium alloy,weaken or suppress the formation ofαmicrotexture,and eliminate continuous grain boundaryαphase.As the forging deformation increases from 67%to 92%,the average size of the originalβgrain andαmicrotexture decreases from 420μm and 80μm to 280μm and 20μm,respectively.With the increase of solution temperature,lathαphase spheroidizes into short rod like and equiaxedαphase,and then transforms intoβphase.The content and size ofαphase gradually decrease,whileβphase shows the opposite trend.With the increase of aging temperature,the lathαphase spheroidizes and the acicular secondaryαphase precipitates in theβmatrix.After solution and aging treatment,the yield strength of the alloy is significantly improved due to the recrystallization of lathαphase and the dispersion and precipitation of nanoscale secondaryαphase in theβmatrix.