摘要
采用高精度差分膨胀仪记录了T91钢在连续冷却过程中的线膨胀行为，获得了试样在奥氏体→马氏体相变过程中的相关动力学信息，在此基础上，根据马氏体形核的几何分割效应以及各向异性生长的特性，建立了相变动力学解析模型，并利用其系统研究了T91在较大冷速（200-3000K／min）下马氏体相变的动力学机制。结果表明：T91钢在连续冷却转变过程中马氏体／奥氏体界面移动速度较小；马氏体相变与原子的热激活有关，并且激活能较小；另外，增加冷速可以使马氏体组织细化和均匀化。
Dilatometric measurements were performed on a continuously cooled T91 ferrite heat-resistant steel using a high-resolution differential dilatometer, from which the necessary kinetic information on austenite-martensite phase transformation was obtained. On this basis, a modular phase-transformation kinetics model was developed according to the classic partitioning analysis for nucleation of martensite and anisotropic growth for impingement, which is used to investigate the kinetic mechanism of the martensite formation in T91 steels with high cooling rates in the range of 200-3000 K/min. The results show that the velocity of the martensite/austenite interface is slow in T91 steel during the continuous cooling process. The martensite transformation is relevant to atomic thermal activation and the activation energy is quite low. Furthermore,increasing the cooling rate can make the martensite microstructure re finement and homogenization
基金
国家自然科学基金(51204121)
天津市高等学校科技发展基金(20100314)
关键词
差分膨胀仪
马氏体相变
相变动力学模型
T91钢
differential dilatometer, martensite phase transformation, phase-transformation kinetic model, T91 steel
