高强Ti-26合金室温压缩性能和显微组织演变研究

Room-Temperature Compressive Properties and Microstructure Evolution of High-Strength Ti-26 Titanium Alloy

摘要:

通过单道次压缩实验研究了压缩速率0.001~0.1S_-1和压缩量20~60%条件下Ti-26合金室温压缩变形行为,分析了Ti-26合金室温压缩力学性能,显微组织演变和变形机制。研究结果表明：相同压缩量条件,压缩速率为0.1S_-1时,真应力-应变曲线存在明显不连续屈服现象,且屈服强度对压缩速率变化更敏感。随着压缩速率、压缩量增加,大变形区晶粒由等轴状变为细长纤维状,且两者增加越大,晶粒伸长程度越显著。室温小变形量条件,合金微观组织存在明显滑移和少量孪晶,位错滑移和孪生协调进行并促进合金室温变形；大变形量条件,滑移占据更多单个β晶粒并向周围β晶粒扩展,大量滑移将少量孪晶完全吞噬,位错滑移成为合金室温变形的唯一机制。

Abstract:

The mechanical properties, microstructural evolution and deformation mechanisms of room-temperature compressive deformation of Ti–26 titanium alloy were investigated using the single pass compression experiment at strain rates of 0.001~0.1 S–1 and height reductions of 20%~60%. The results show that discontinuous yielding appears at a strain rate of 0.1 S–1 and the yield strength are more sensitive to the changes of the compression rate in the same height reductions. With increasing strain rates and height reductions, the initially equiaxial grains evolve into fibrous grains and the larger the height reductions and strain rates are, the more significant the elongation of the beta grains are. Small deformation condition, the microstructure of Ti-26 alloy has obvious slip and a small amount of twinning, and dislocation slip and twinning mutual coordinate and promote the alloy deformation at room temperature. Large deformation condition, The slip occupy more the single β grain and expand around the β grain, a small amount of twins can be completely engulfed, dislocation slip only coordinated deformation mechanism.