Nb-Ti微合金钢高温变形软化行为力学分析及析出物电镜分析

研究了Nb-Ti微合金钢高温变形时的软化行为和微合金钢动态和静态析出物的电镜分析.通过双道次恒应变速率压缩实验,从流变应力曲线用卸载法求出了不同热变形条件下的软化分数,并建立了静态再结晶、亚动态再结晶动力学模型,计算出静态再结晶、亚动态再结晶的表观激活能.同时,还对静态和动态析出行为进行了探讨,讨论了析出对软化行为的影响,并通过透射电子显微镜对析出物的形貌、大小、分布进行了观察,用衍射图谱进一步确定了析出物的成份.

Mechanical Analysis of Softening and TEM Observation of Precipitation under High Temperature Deformation Conditions for Nb-Ti Microalloyed Steels

The softening behavior and static and dynamic precipitation were investigated under high temperature deformation conditions for Nb Ti microalloyed steel. Double stage interrupted compression tests with constant strain rate were carried out for the Nb Ti microalloyed steels to investigate two typical static restoration behaviors, i.e., meta dynamic recrystallization and sta tic recrystallization process. The softening fraction was obtained with the offset method. The results in apparent activation energy for the SRX and MDRX were Q SRX =316 6 kJ/mol, Q MDRX =219.4 kJ/mol, respectively. The behaviors of static and dynamic precipitation have also been investigated. The sizes and distribution of the particles were observed by means of a transmission electron microscope (TEM) and the components of the precipitation were identified.