固溶时间对Ti-5553显微组织及拉伸性能的影响

Effect of Solution Time on Microstructures and Mechanical Properties of Ti-5553 Alloy

研究了两相区不同固溶时间对Ti-5553合金显微组织及拉伸性能影响。利用扫描电镜观察显微组织随固溶时间的演化行为,重点分析了初生α相(α_p)比例及长宽比分布随固溶时间的变化规律,利用EBSD技术表征了固溶保温阶段晶界α相及晶内α的晶体取向演化,利用电子万能试验机进行了室温拉伸性能测试。结果表明:随着固溶时间的增加,初生α比例降低,等轴化程度增加,进一步导致拉伸塑性变形过程中位错运动的阻力及合金强度降低;晶界α_p在固溶过程中是以"热切口"的形式发生截断,然而截断部分晶体取向仍保持一致。

The effects of varied solution time on the microstructures and tensile properties in α+β phase field of Ti-5553 alloy were studied. The volume fraction and Feret ratio distribution of primary α(α_p) with varied solution time were emphatically analyzed. The microstructures of Ti-5553 alloy were observed by SEM. The orientation evolution of grain boundary primary α and intragranular α phase during solution was characterized by EBSD technique. The tensile properties were tested by an electronic universal testing machine. The results show that the volume fraction of αp decreases with the extension of solution time;meanwhile, the equiaxation and coarsening of αp decrease the resistance to dislocation movement, which result in the decrease of strength and the increase of plasticity. The grain boundary α_p is truncated in the form of "hot trench" during solution process;however the truncated grain boundary αp maintains the same orientation.