变形温度对TC11钛合金超塑性的影响

Effect of Deformation Temperature on the Superplasicity of Titanium Alloy TC11

摘要:

通过高温拉伸试验研究TC11钛合金在应变速率0.001 s-1、变形温度810~1050 ℃的超塑性变形行为，并用金相显微镜和透射电镜对变形试样的微观组织进行观察和分析。结果表明，在β单相区，TC11钛合金不能呈现超塑性；而在α+β两相区的810~980℃温度范围内，TC11钛合金呈现出超塑性，且最佳温度在900 ℃附近，其最大延伸率为595%，此时的超塑性变形过程中有晶内变形、界面滑动、动态再结晶或扩散蠕变的参与，且界面滑动出现在α/β相界面。α相和β相的相对含量对超塑性有较大的影响，初生相含量在70%附近时对应着TC11钛合金的最佳超塑性

Abstract:

The superplastic deformation behavior of titanium alloy TC11 has been investigated in the temperature range of 810~1050 ℃ at the strain rate of 0.001 s-1 by tensile tests at high temperature, and the microstructures of samples deformed have been observed and analysed by metallographic microscope and transmission electron microscope. The results showed that the titanium alloy TC11 would not exhibit superplasicity in the b phase field, but exhibit in the temperature range of 810~980 ℃ in the a+b phase field with an optimal deformation temperature of near 900 ℃ and maximum elongation of 595%. The intracrystalline deformation, interface sliding, dynamic recrystallization or diffusion creep take part in the superplastic deformation at 900 ℃, and the interface sliding appears at a/b phase interface. The relative content of a and b phases has a heavy effect on the superplasicity and the titanium alloy TC11 exhibits an optimal superplasicity when the content of primary a phase is about 70%.