冷轧及退火对310S奥氏体不锈钢的微观结构和组织的影响:基于X射线和电子背散射衍射分析

Microstructure and texture evolutions of 310S austenitic stainless steel after cryogenic rolling and subsequent annealing:X-ray and electron backscatter diffraction studies

本文研究了热处理对310S奥氏体不锈钢的微观结构和组织的影响。对样品材料进行冷轧,使其厚度分别减少20%、50%和90%,然后在1023、1223和1323 K下退火5、15和30 min。在厚度减少20%后,奥氏体内产生孪晶,且可观察到形变诱发的α’马氏体,孪晶的体积分数大于α’马氏体。当厚度变化由50%增加到90%,α’马氏体的体积分数由11%增加到69%,孪晶被α’马氏体取代。发生形变后奥氏体相主要为Brass、Goss和S织构,α’马氏体的主要纹理为R-Cu、R-cube、F和E组份。随着形变量增大,Brass织构增加,Goss织构减少。退火过程中,马氏体向奥氏体转变,并发生了再结晶,使Goss和Brass再结晶织构的体积分数增加。材料退火后的结构与冷轧后的大致相同。1223 K下退火5 min的马氏体转变速度明显高于1023 K下的。在1023 K下退火5 min,由于马氏体不完全转变和初级再结晶,未能检测到等轴组织。获得超细晶粒组织的最佳退火温度为1023 K,退火时间为15 min。在1173 K和1273 K时出现快速再结晶和晶粒生长。

The present work aims to study the microstructure and texture evolutions of thermomechanically processed 310S austenitic stainless steel.The material was cryo-rolled at 20%,50%and 90%thickness reduction,followed by annealing at 1023,1223 and 1323 K for 5,15 and 30 min,respectively.After a 20%thickness reduction,strain-inducedαʹ-martensite was seen along with deformation twinning within the austenite grains.The volume fraction of the deformation twinning was higher than that ofαʹ-martensite.By increasing deformation from 50%to 90%,the volume fraction ofαʹ-martensite went from 11%to 69%,and twinning was replaced by martensite.Brass,Goss,and S components were the dominant textures in the austenite phase after deformation,while the main texture components inαʹ-martensite were R-Cu,R-cube,F,and E.Brass component was further increased by increasing the thickness reduction in contrast to the Goss component.During annealing,martensite to austenite reversion and recrystallization occurred in the deformed austenite,which resulted in an increase in the volume fractions of the Goss and Brass recrystallization components.However,the annealing texture of the alloy was found to be approximately the same as the cryo-rolling texture.The kinetics of martensite reversion at 1223 K for 5 min was much faster than that at 1023 K.An equiaxed microstructure was not detected at 1023 K for 5 min due to incomplete martensite reversion and primary recrystallization.The optimum annealing temperature for obtaining an ultrafine grain structure was 1023 K for 15 min.Recrystallization and tangible grain growth swiftly occurred at 1173 K and 1273 K.