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采用Gleeble-1500热模拟试验机对Ti-2Al-9.2Mo-2Fe合金进行850~1000℃、应变速率0.01~10 s-1的高温压缩变形试验。结果表明,热压缩后合金的显微组织为拉长的β晶粒和锯齿状的β晶界。低应变速率(0.01 s-1和0.1 s-1)时,原始β晶界处形成了大量小角度晶界以及少量的再结晶晶粒组织;高应变速率(1 s-1和10 s-1)时,原始β晶界附近形成了大量细小的再结晶晶粒组织。热压缩过程中,合金在屈服之后随应变速率的变化呈现出不同的应变硬化或软化现象。应变速率较高时,合金呈现出明显的应变硬化效应,流变应力出现非常明显的周期性震荡,当应变速率为1 s-1时,未出现应变软化现象,而应变速率为10 s-1时,可观察到明显的流变软化阶段;应变速率较低时,高温(950℃和1000℃)压缩条件下,合金在屈服之后立即进入流变稳态阶段,无明显的流变硬化或软化现象。而在低温(850℃和900℃)压缩时,屈服之后出现轻微的流变硬化现象。
The Gleeble-1500 thermal simulator was used to test the high temperature compressive deformation of Ti-2Al-9.2Mo-2Fe alloy at 850-1000 ℃ and strain rate of 0.01-10 s-1. The results show that the microstructure of the alloy after hot compression is elongated β grains and jagged β grain boundaries. At low strain rates (0.01 s-1 and 0.1 s-1), a large number of small-angle grain boundaries and a small amount of recrystallized grain structure were formed at the original β grain boundaries. High strain rates (1 s-1 and 10 s-1) ), A large number of fine recrystallized grains were formed near the original β grain boundaries. During hot compression, the alloy shows different strain hardening or softening with the change of strain rate after yielding. When the strain rate is high, the alloy shows obvious strain hardening effect, and the flow stress shows very obvious periodic oscillation. When the strain rate is 1 s-1, the strain softening phenomenon does not occur, but the strain rate is 10 s-1 When the strain rate is low, the alloy enters the steady-state stage of rheology immediately after yielding under the condition of high temperature (950 ℃ and 1000 ℃), and there is no obvious rheological hardening or softening phenomenon. At low temperatures (850 ° C and 900 ° C) compression, a slight rheological hardening occurs after yielding.