钛合金表面氩弧熔覆TiC增强复合涂层组织与性能分析
Microstructure and properties of TiC reinforced composite coating fabricated on Ti alloy by GTAW
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摘要: 把石墨粉末预涂在钛合金表面上,利用氩弧熔覆技术成功制备出原位自生TiC增强的金属基复合涂层。利用扫描电镜、X射线衍射仪和能谱仪分析了熔覆涂层的显微组织,探讨了增强相TiC的生成机制;利用显微硬度仪测试了复合涂层的显微硬度并用磨损试验机考察了其在室温干滑动磨损条件下的耐磨性能。结果表明,氩弧熔覆涂层组织均匀致密,原位自生TiC呈树枝晶和细碎的条状均匀地分布于整个涂层中;由TiC增强的复合涂层明显地改善了钛合金的表面硬度,平均硬度约为700 HV0.2且沿层深方向呈梯度分布;涂层在室温干滑动磨损条件下的耐磨性明显优于基体,约为钛合金的10.5倍。Abstract: A metal matrix composite coating reinforced by TiC particulates has been successfully fabricated utilizing the in-situ reaction of pre-placed C powder on Ti alloy by gas tungsten arc welding (GTAW)process.The microstructure of the coating was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD)and energy-dispersive spectrum (EDS).The growing mechanism of TiC was discussed.Microhardness and wear resistance at room temperature of the composite coating were examined by means of Microhardness Tester and Wear Tester respectively.The results show that microstructure of the composite coating is uniform and the fine TiC exhibites dendrite and strip shapes.The composite coating reinforced by in-situ TiC apparently improves surface hardness of Ti alloy, the average microhardness can reach HV700, and its gradient distribution appears.Wear resistance of the composite coating is about 10.5 times of Ti alloy's substrate.