稀土对20MnCrNi2Mo耐磨铸钢过冷奥氏体转变的影响及机理

发布时间：2018-04-03 23:57

本文选题：镧铈混合稀土　切入点：固溶　出处：《稀有金属材料与工程》2017年04期

【摘要】：采用L78 RITA淬火热膨胀仪、QUANTA400扫描电镜和JEM-2100透射电镜研究镧铈混合稀土对20MnCrNi2Mo耐磨铸钢过冷奥氏体连续冷却转变动力学及显微组织的影响,采用电感耦合等离子体质谱仪测定稀土的固溶量,通过透射电镜探索固溶稀土在钢中的存在状态,结合对La的界面扩散系数的测定、计算,综合分析镧铈混合稀土的作用机理。结果表明,镧铈混合稀土使20MnCrNi2Mo耐磨铸钢CCT曲线整体向右下方移动,促进了连续冷却转变过程中下贝氏体的形成,提高了淬透性,使得板条马氏体组织中孪晶亚结构增加。分析认为,固溶于钢中的稀土原子富集于晶界等晶体缺陷处,降低晶界能、阻塞扩散通道,推迟新相的形核-长大过程,进而影响组织转变。
[Abstract]:The effects of lanthanum and cerium mixed rare earths on the continuous cooling transformation kinetics and microstructure of undercooled austenite of 20MnCrNi2Mo wear-resistant cast steel were studied by means of scanning electron microscope (SEM) and JEM-2100 transmission electron microscope (TEM).The solid solution of rare earths was determined by inductively coupled plasma mass spectrometer. The existence of rare earths in steel was investigated by transmission electron microscope. The mechanism of lanthanum and cerium mixed rare earth was analyzed synthetically with the determination of interfacial diffusion coefficient of La.The results show that lanthanum and cerium mixed rare earth can make the CCT curve of 20MnCrNi2Mo wear-resistant cast steel move to the lower right, promote the formation of lower bainite during the continuous cooling transformation, improve hardenability, and increase the twin substructure in the lath martensite structure.It is considered that the rare earth atoms in the steel are concentrated in the grain boundary and other crystal defects, reduce the grain boundary energy, block the diffusion channel, delay the nucleation and growth process of the new phase, and then affect the microstructure transformation.
【作者单位】：上海大学;内蒙古科技大学;内蒙古自治区白云鄂博矿多金属资源综合利用重点实验室;
【基金】：国家自然科学基金(51261018) 内蒙古自然科学基金(2012MS0805) 内蒙古科技大学创新基金(2011NCL037)
【分类号】：TG142.1

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