激光3D打印H13/WC-Co复合涂层组织及性能研究

Research on Microstructure and Properties of Laser 3D-printed H13/WC-Co Composite Coatings

采用YLR-2000型连续光纤激光器制备H13合金基层,然后在其表面熔覆WC-Co覆层,通过正交试验分析激光功率、扫描速度和送粉量对覆层成形质量的影响,并确定最佳参数。借助光学显微镜和扫描电镜分析复合涂层组织形貌,使用显微硬度计测试H13/WC-Co复合涂层的纵截面显微硬度。结果显示,激光功率对WC-Co覆层的熔宽和熔高影响最大,扫描速度和送粉量对熔宽和熔高影响较小。优化的工艺参数为:激光功率600 W、扫描速度8 mm/s、送粉量6 g/min。经激光3D打印后的H13合金基层的顶部组织主要为网状枝晶,底部主要为柱状枝晶,WC-Co熔敷覆层组织主要由胞状晶和等轴树枝晶两部分组成,覆层和基层之间形成了良好的冶金结合。复合涂层的横截面显微硬度从基层到覆层的方向逐渐增大,基层的平均显微硬度约为464.21 HV0.1,覆层平均显微硬度约为1218.11 HV0.1,约为基层显微硬度的2.62倍。

WC-Co coating was cladded on the surface of H13 by YLR-2000 continuous fiber laser,and the influence of power,scanning speed and powder feeding amount on the forming quality of the coating was analyzed by orthogonal experiment to determine the best parameters.The morphology of the coating structure was analyzed by optical microscope and SEM.The hardness of the coating was tested using Vickers hardness tester.The results indicate that the laser power has the greatest effect on the melt width and height of the coating,while the scanning speed and powder feed rate have little effect on the melt width and melt height of the coating.The optimized process parameters as follows:laser power 600 W,scanning speed 8 mm/s,powder feed rate 6 g/min.The top microstructure of the H13 alloy base after laser 3D printing is mainly mesh branch crystal,the bottom is mainly columnar branch crystal.The microstructure of the WC-Co melting coating mainly consists of cellular crystals and equiaxed dendrites.A good metallurgical bond is formed between the coating and the base layer.The hardness of cross section of the composite coating decreases gradually from the coating to the base layer.The average microhardness of the base layer is 464.21 HV0.1,and the average microhardness of the coating is 1218.11 HV0.1,which is 2.62 times of that of the base layer.