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利用热模拟试验机对铸态Ti40合金在950～1100℃、0.001～1.0s-1条件下进行热压缩试验,研究了应变速率对该合金流动应力和变形组织的影响。结果表明,流动应力随应变速率的增大而增大,不同温度和应变速率的真应力-真应变曲线呈稳态流动型。温度越低,发生动态再结晶的应变速率越小,且动态再结晶晶粒的体积分数和平均晶粒尺寸均随应变速率的减小而增大。在实验热力参数下的动态再结晶程度比较低,最大的体积分数在20%左右,再结晶晶粒的平均尺寸为19.2～47.0μm。从降低能耗和提高加工性能等角度考虑,在950～1000℃,应变速率以小于0.1s-1为宜;在1050℃附近,应变速率以小于1.0s-1为宜;在1100℃附近,应变速率以1.0～0.001s-1较适宜。
The hot compression tests were carried out on the as-cast Ti40 alloy at 950-1100 ℃ and 0.001-1.0 s-1 using a thermal simulator. The effect of strain rate on the flow stress and deformation microstructure of the alloy was investigated. The results show that the flow stress increases with the increase of strain rate, and the true stress-strain curves of steady-state flow at different temperature and strain rate are steady. The lower the temperature, the smaller the strain rate of dynamic recrystallization and the increase of the volume fraction and the average grain size of dynamic recrystallized grains with decreasing strain rate. Under the experimental thermodynamic parameters, the degree of dynamic recrystallization is relatively low, the maximum volume fraction is about 20% and the average recrystallization grain size is 19.2 ~ 47.0μm. From the perspective of reducing energy consumption and improving processability, the strain rate should be less than 0.1s-1 at 950-1000 ℃, and the strain rate should be less than 1.0s-1 at around 1050 ℃. At 1100 ℃, Strain rate to 1.0 ~ 0.001s-1 more appropriate.