TA15钛合金等温近β变形行为及微观组织演化

Deformation Behavior and Microstructure Evolution of TA15 Titanium Alloy after Isothermal near β Deformation

摘要:

通过热模拟压缩实验研究了TA15钛合金等温近β变形行为和微观组织演化，定量分析揭示了近β变形温度、应变速率、变形量对TA15合金流动应力和微观组织的影响。结果表明：在近β变形过程中，变形温度升高，应变速率降低，将抑制动态再结晶过程，促进动态回复过程；变形温度降低，应变速率升高，将抑制动态回复过程，促进动态再结晶过程。变形温度是影响等轴α相含量，晶粒尺寸和平均轴比的主要因素，增加应变速率对等轴α相晶粒细化的作用并不明显。在近β温度区间，建立了等轴α相含量和晶粒尺寸与变形温度关系的经验模型。研究结果可为TA15钛合金等温近β成形工艺优化控制提供依据

Abstract:

The deformation behavior and microstructure evolution after isothermal near β deformation of TA15 titanium alloy with initially equiaxed microstructure were investigated by compression tests. The effects of deformation temperature, strain and strain rate on the deformation behavior and microstructure transformation were quantitatively characterized through metallographs analysis. Results show that dynamic recrystallization is suppressed and dynamic recovery is promoted with the deformation temperature increasing or the strain rate decreasing. Otherwise dynamic recrystallization is promoted and dynamic recovery is suppressed with the deformation temperature decreasing or the strain rate increasing. Deformation temperature is the primary factor influencing the volume fraction, the size and the aspect of equiaxed α. Increasing strain rate has little effect on the refinement of equiaxed α. The empirical model was developed to describe the relationship between deformation temperature and the volume fraction as well as the size of equiaxed α in the near β temperature range. The research results can provide a guide for process optimization and control of isothermal near β deformation of TA15 titanium alloy