摘要
利用金相观察、热模拟技术及扫描电子显微术(SEM)研究了Fe-40%Ni合金在含Ti及无Ti条件下的高温应力-应变行为及变形后的应力弛豫行为,并观察了锻造样品中TiN颗粒的形态。实验结果显示:含Ni 40%的Fe-Ni合金在室温下保持了奥氏体组织,并有孪晶出现。在800～950℃范围内变形时只发生动态回复,1000℃以上变形时发生了动态再结晶。在Ti存在的情况下,变形温度达到1150℃时才发生动态再结晶。IF钢的模拟结果与不含Ti的Fe-40Ni合金呈现类似的趋势。由于TiN的应变诱导析出,明显延缓了变形后等温过程中的应力松弛速率。
The metallographic observation, scanning electron microscopy（SEM） and thermo-simulation test were used to investigate the stress-strain relation at high temperature and stress relaxation behavior after deformation of Ti bearing and Ti-free Fe-40%Ni alloys. TiN precipitates are observed in the as-forged samples. The experimental results demonstrate that, the Fe-40Ni alloys remain the fcc austenitic structure at the room temperature accompanied by a little twin structures. When deformed at 800-950 ℃, only dynamical recovery happened, dynamic recrystalliza- tion occurs in the Ti free Fe-40Ni alloy above 1000℃. While in the Ti-bearing Fe-40Ni alloy, dynamic recrystalliza- tion didn＇t happen till 1150℃. The simulation results of IF steel reveals the similar trend with Ti-free Fe-40Ni alloy. The decreasing of stress after deformation slows down due to the stain induced TiN precipitates.
基金
河北省杰出青年科学基金(E2012105005)
新金属材料国家重点实验室开放基金(2012-Z05)
