Ti-25Al-14Nb-2Mo-1Fe合金热压缩变形流变应力行为与微观组织演变的研究

在Gleeble-3500热模拟试验机上对Ti-25Al-14Nb-2Mo-1Fe合金进行了等温恒应变速率压缩试验,研究了在变形温度为950~1 100℃,应变速率为0.001~1 s-1,最大变形程度为50%的条件下合金的热压缩变形流变应力行为与微观组织演变。结果表明:Ti-25Al-14Nb-2Mo-1Fe合金的流变应力对变形温度和应变速率均较为敏感,其流变应力曲线具有应力峰值、流变软化和稳态流变的特征。在变形温度为950℃,应变速率为0.001~0.1 s-1的条件下,Ti-25Al-14Nb-2Mo-1Fe合金的热变形特性为片层组织球化,其热变形机制可用晶界分离球化模型进行解释说明;在变形温度为1 000~1 100℃,应变速率为1 s-1的条件下,材料只发生了动态回复现象;在变形温度为1 050~1 100℃,应变速率为0.001~0.1 s-1的条件下,材料发生了动态再结晶现象。

Research on Flow Stress Behavior and microstructure Evolution During Hot Compression of Ti-25 Al-14 Nb-2 mo-1 Fe Alloy

The flow stress behavior and microstructure evolution of Ti-25 Al-14 Nb-2 Mo-1 Fe alloy was investigated at deformation temperatures between 950 ℃ and 1 100 ℃ with strain rate between 0. 001 s-1 and 1 s-1 ,and the heigh-test reduction of 50% by using isothermal compression testing on Gleeble-3500 simulator. The results show that the flow stress of the alloy is sensitive to the variation of deformation temperature and strain rate. The stress-strain curves exhibit a peak flow stress,flow softening and steady state flow behavior. The hot deformation microstructure feature of Ti-25Al-14Nb-2Mo-1Fe alloy deformed at 950 ℃,0. 001-0. 1 s-1 is lamellar globularization. The dominant deforma-tion mechanism is illustrated by the models of the splitting of grain boundaries. The hot deformation microstructure feature of the alloy deformed at 1 s-1 ,1 000 -1 100 ℃ is dynamic recovery. The hot deformation microstructure feature of the alloy deformed at 1 050-1 100 ℃,0. 001-0. 1 s-1 is dynamic recrystallization.