等离子堆焊原位合成WC增强Ni基合金改性层

为了进一步提高Ni基合金的耐磨性能,采用等离子堆焊技术在304L奥氏体不锈钢表面原位合成WC增强Ni基合金改性层.利用光学显微镜、扫描电子显微镜和能谱仪、X射线衍射仪、显微硬度计及销-盘磨损试验机等设备对改性层的显微组织、成分、显微硬度及摩擦磨损性能进行研究.结果表明:当Ni基合金改性层中直接加入WC颗粒时,WC颗粒出现"沉底"现象,改性层组织不均匀,而通过原位反应合成的WC相呈块状弥散分布于整个改性层,加入适量的氧化钇后,改性层组织变得细小致密,WC增强相的形态、尺寸和分布等均发生了变化,改性层硬度显著提高,耐磨性提高了2倍以上.

In situ synthesis of WC reinforced Ni based alloy modified layer with PTAW

In order to further improve the wear resistance of Ni based alloy, the WC reinforced Ni based alloy modified layer was in situ synthesized on the surface of 304L austenitic stainless steel with the plasma transferred arc welding （PTAW） technology. The microstructure, chemical composition, microhardness, friction and wear properties of modified layer were investigated with the optical microscope, scanning electron microscope （SEM）, energy dispersive X ray spectroscope （EDS）, X ray diffractometer （XRD）, microhardness tester and pin dish abrasion tester. The results show that when the WC particles were directly added into the Ni based alloy modified layer, the sink phenomenon of WC particles appears, and the microstructure of modified layer is nonuniform. However, the in situ synthesized WC phase is massively and uniformly distribute in whole modified layer. After adding the moderate amount of Y₂O₃, the microstructure of modified layer becomes fine and compact, and the morphology, size and distribution of WC reinforcement phase get changed. Furthermore, the microhardness of modified layer significantly increases, and the wear resistance increases by above two times. 