摘要
利用热膨胀相变仪、光学显微镜、扫描电镜及高分辨透射电镜研究了22MnCrNiMo钢过冷奥氏体在不同冷速下的相变产物及其相变机制。结果表明:冷却速度在2~20℃/s范围内时,相变产物是板条马氏体和针状马氏体,整个马氏体相变分为板条马氏体形成阶段(315~400℃)和针状马氏体形成阶段(230~315℃)。在连续冷却过程中,由于控制马氏体切变方式的临界分切应力受温度和合金元素的影响,冷却至Ms以下的过冷奥氏体优先形成以位错亚结构为主的板条马氏体,随着温度的降低,富碳奥氏体逐渐转变为以孪生亚结构为主的针状马氏体。针状马氏体体积分数随冷速的增加逐渐降低。
By means of high-resolution dilatometer, optical microscope, scanning electron microscopy and high resolution transmission electron microscopy, the transformation products and their phase transition mechanism of super-cooled austenite of 22 MnCrNiMo steel at different cooling rates were studied. The results show that when the cooling rate is in the range of 2-20 ℃/s, the transformation products are lath martensite and acicular martensite, and the overall martensite transformation is divided into lath martensite formation stage(315-400 ℃) and acicular martensite formation stage(230-315 ℃). During continuous cooling, the super-cooled austenite cooled below M_s preferentially forms lath martensite dominated by dislocation substructure because the critical shear stress controlling the martensite shear mode is affected by temperature and alloy elements. With the decrease of temperature, carbon-rich austenite gradually transforms into acicular martensite dominated by twin substructure. The volume fraction of the acicular martensite decreases gradually with the increase of cold rate.
作者
赵四新
薛兴坤
王建军
ZHAO Si-xin;XUE Xing-kun;WANG Jian-jun(Central Research Institute,BaoShan Iron&Steel Co Ltd,Shanghai 201999,China;Key Laboratory for Anisotropy and Texture of Materials(MOE),School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China;School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China)
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2021年第1期126-131,共6页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(U1860201,U1960115)。
