稀土La对42CrMo钢碳化物析出特征及摩擦学性能增强机理研究  

Effect of Rare Earth La on the Precipitation Characteristics of Carbides in 42CrMo Steel and the Mechanism of Enhanced Tribological Properties

作　　者：吉宏斌 王建梅[1] 程先华[2] 王震宇 王强[1] JI Hongbin;WANG Jianmei;CHENG Xianhua;WANG Zhenyu;WANG Qiang(Engineering Research Center of Heavy Machinery Ministry of Education,Taiyuan University of Science and Technology,Shanxi Taiyuan 030024,China;School of Mechanical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]太原科技大学重型机械教育部工程研究中心,山西太原030024 [2]上海交通大学机械与动力工程学院,上海200240

出　　处：《摩擦学学报（中英文）》2024年第8期1032-1042,共11页Tribology

基　　金：国家自然科学基金重点项目(52035006)资助。

摘　　要：使用真空熔炼技术制备了稀土42CrMo钢,采用光学显微镜(OM)、扫描电子显微镜(SEM)和能谱仪(EDS)对材料微观组织、拉伸断口、磨损表面和亚表层进行了表征,研究了La对42CrMo钢碳化物析出特征及摩擦学性能增强机理.结果表明:La减小了晶界张力和界面能,降低了碳化物沉淀所需成核势垒,提供了形核点,使42CrMo钢具有更小的原奥氏体晶粒和碳化物,原奥氏体和碳化物尺寸减少约46.5%和19.4%.添加La后,42CrMo钢具有更优良的力学和摩擦磨损性能,屈服强度、抗拉强度和断后伸长率比普通钢提升了9.29%、9.48%和25.01%,磨损率降低了36.71%.稀土钢强塑性的提高得益于La对晶粒和碳化物的细化以及碳化物和基体界面柔韧性的提高.摩擦磨损性能的提升是由于碳化物和基体的柔性界面在摩擦磨损过程中起到协调变形作用,减少了微裂纹的形成和碳化物的剥离,使摩擦表面形成的自润滑膜更加致密、完整,不易破坏.此外,La减少了钢中夹杂物,也提高了稀土钢的塑性和摩擦磨损性能.Rare earth 42CrMo steel was prepared by vacuum melting technology.The microstructure,tensile fracture,wear surface and subsurface of the material were characterized by optical microscope(OM),scanning electron microscope(SEM)and energy dispersive spectrometer(EDS).The improvement of carbide precipitation characteristics and enhancement mechanism of tribological properties in 42CrMo steel by La were studied.The results showed that La could make 42CrMo steel have smaller austenite grains and carbides by increasing nucleation points and reducing grain boundary tension,interface energy and carbide nucleation barrier.The prior austenite and carbide sizes of rare earth steel were reduced by about 46.5%and 19.4%,respectively.After adding La,42CrMo steel had better mechanical and tribological properties.Compared with normal steel,the yield strength,tensile strength and elongation after fracture were increased by 9.29%,9.48%and 25.01%,and the wear rate was reduced by 36.71%.The enhancement of the strength and plasticity of rare-earth steel is attributed to improving the interface flexibility between carbide and matrix and the refinement of grain and carbide.The tribological properties improve due to the flexible interface between the carbide and the matrix that coordinates the deformation during the friction and wear.It reduces the formation of microcracks and peeled carbides,making the self-lubricating film formed on the friction surface denser,more complete and less prone to damage.In addition,La also improves the plasticity and tribological properties of rare earth steel by reducing inclusions.

关 键 词：稀土La 42CRMO钢 碳化物 摩擦学性能 柔性界面 

分 类 号：TH117.1[机械工程—机械设计及理论]