对TC6钛合金在800~900℃温度区间内,分别进行应变速率为0.0001~0.1 s-1的恒应变速率法拉伸实验和最大m值法超塑性拉伸实验,获得拉伸过程应力-应变曲线,并采用金相显微镜对拉伸后断口附近显微组织进行分析。结果表明：TC6合金表现出良好的超塑性性能,随着应变速率或温度的升高,伸长率先增大后减小,恒应变速率拉伸时,在温度850℃、应变速率0.001 s-1条件下伸长率可达到993%；在同一变形温度下最大m值法拉伸能获得比恒应变速率法更好的超塑性,850℃时伸长率达到1353%；TC6合金在超塑性变形过程中发生了明显的动态再结晶,并随着应变速率和温度的升高动态再结晶行为增强。
The superplastic tensile tests of TC6 alloy were conducted in the temperature range of 800-900 ℃ by using the maximum m value superplasticity deformation ( Max m SPD) method and the constant strain rate deformation method at the strain rate range of 0. 0001-0. 1 s-1 . The stress-strain curve of the tensile tests was obtained and the microstructure near the fracture were analyzed by met-allographic microscope. The result shows that the superplasticity of TC6 alloy is excellent, and the elongation increases first and then decreases with the increase of strain rate or temperature. When the temperature is 850 ℃ and strain rate is 0. 001 s-1 at constant stain rate tensile tests, the elongation reaches up to 993%. However, the elongation using Max m SPD method at 850 ℃ is 1353%. It is shown that the material can achieve better superplasticity by using Max m SPD tensile compared to constant stain rate tensile under the same temperature. The superplastic deformation of TC6 alloy can enhance the dynamic recrystallization behavior significantly, the dy-namic recrystallization behavior is promoted when strain rate and temperature are increased.
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