原位合成TiC-M7C3陶瓷硬质相显微组织的分析

采用等离子弧堆焊技术原位合成TiC-M7C3陶瓷硬质相,探讨堆焊层中TiC-M7C3硬质相对堆焊层耐磨性的影响.利用X射线衍射仪（XRD）、扫描电镜（SEM）、能谱分析仪（EDS）、洛氏硬度计及湿砂磨损试验机等设备进行检测分析.结果表明,堆焊层是由高碳马氏体基体和大量弥散分布在基体中的TiC,M7C3陶瓷硬质相构成的过共晶组织;堆焊层表面的洛氏硬度为66.4 HRC,磨损量为0.086 g.TiC可以作为M7C3陶瓷硬质相的形核核心,提高了M7C3陶瓷硬质相的形核率,促使其晶粒细化;在TiC和M7C3陶瓷硬质相的共同作用下,Fe-Cr-Ti-C系合金比相同Cr元素含量的Fe-Cr-C系合金堆焊层的硬度更高,抗磨损性能更好.

Analysis on microstructure of in-situ synthesis TiC-M7C3 ceramic hard phase

TiC-M7C3 ceramic hard phases were in situ synthesized using plasma arc surfacing technology.The morphology and distribution of TiC-M7C3 hard phases in the surfacing layer was investigated with the X-ray diffraction(XRD),optical microscope(OM),scanning electron microscope(SEM) and spectrum analyzer(EDS).Rockwell hardness tester and wet sand abrasion tester were used to examine the performance of the surfacing layer.The results show that the microstructure of the surfacing layer consists of high-carbon martensite and a large number of ceramic hard phases,for example,TiC and M7C3,which disperse in the matrix of surfacing layer.The hardness of the surfacing layer is 66.4 HRC and the weight reduction is 0.086 g.TiC can act as the nuclei of M7C3 to improve the nucleation rate of M7C3 ceramic hard phases and grain refinement.The Fe-Cr-Ti-C surfacing layer has higher hardness and better wear resistance than Fe-Cr-C alloy due to the combined effect of TiC and M7C3 ceramic hard phases.