稀土对20MnCrNi2Mo耐磨铸钢过冷奥氏体转变的影响及机理  

Effect of Rare Earth on Super-cooled Austenite Transformation of 20MnCrNi2Mo Wear-resistant Cast Steel and Its Mechanism

作　　者：计云萍[1,2] 任慧平[1,3] 刘新华[2,3] 侯敬超[2] 金自力[2] 

机构地区：[1]上海大学,上海200072 [2]内蒙古科技大学,内蒙古包头014010 [3]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,内蒙古包头014010

出　　处：《稀有金属材料与工程》2017年第4期997-1002,共6页Rare Metal Materials and Engineering

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)

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。The effects of lanthanum-cerium mischmetal on the kinetics and the microstructure of the super-cooled austenite continuous cooling transformation in 20MnCrNi2Mo wear-resistant cast steel were studied by L78 RITA quenching thermal dilatometer, QUANTA-400 scanning electron microscope and JEM-2100 transmission electron microscope. The inductively coupled plasma mass spectrometry was used to measure the amount of the solid-solution rare earth and the JEM-2100 transmission electron microscope was used to probe the existential state of the solid-solution rare earth. The action mechanism of the solid-solution rare earth was analyzed combined with the measurement of the interface diffusion coefficient of La. Results show that the CCT curves are moved to the bottom right, the hardenability is improved and the twin substructure in lath martensite is increased due to the effect of the rare earth. A trace amount of solid-solution rare earth can exist in grain boundary, dislocation and other crystal defects. They can reduce the grain boundary energy, block the diffusion channels and then defer the nucleation and growth of the new phase. So the phase transformation and the microstructure are influenced.

关 键 词：镧铈混合稀土 固溶 20MnCrNi2Mo耐磨铸钢 CCT曲线 孪晶 

分 类 号：TG142.1[一般工业技术—材料科学与工程]