中锰钢中原奥氏体晶粒尺寸对马氏体相变的影响

对中锰钢中原奥氏体晶粒尺寸对马氏体相变动力学的影响进行了分析.利用SEM、XRD、热膨胀相变仪和EBSD等检测手段,研究了不同原奥氏体晶粒尺寸下马氏体相变速率和马氏体板条组织的变化.通过不同温度的奥氏体化处理,分别得到了尺寸为(190±15)、(36±2)、(11±2)和(4.8±2)μm的原奥氏体晶粒.结果表明:随着...

Effect of prior austenite grain size on martensitic transformation in medium manganese steel

Effect of prior austenite grain size in medium manganese steel on kinetics of martensitic transformation was studied. The kinetics of martensitic transformation and microstructure evolution were analyzed by combining with SEM, XRD, thermal dilatometer and EBSD results. Different prior austenite grain sizes with (190±15), (36±2), (11±2) and (4.8±2) μm were achieved, respectively, by heating at different austenitizing temperatures. The results show that with the decreasing of prior austenite grain size, the martensite start temperature decrease from 289 ℃ to 250 ℃, while the kinetic of martensitic transformation increase at first then decrease. The kinetics of martensitic transformation is closely related to the number of martensite nucleation cites per unit volume, while the number of martensite nucleation cites are closed to the prior austenite grain size and the martensite lath aspect ratio. When the size of prior austenite grain decreases to 5 μm, the aspect ratio of martensite lath increases, while the increase rate of martensite nucleation cites with undercooling significantly reduces, which results in the decrease of the rate of martensite transformation.