钛合金表面直接激光熔覆Al_2O_3-13%TiO_2涂层互熔稀释特性

Dilution Characters of Al_2O_3-13wt%TiO_2 Coating by Direct Laser Cladding on Titanium Alloy

采用同轴送粉激光熔覆技术,在Ti-6Al-4V合金表面进行Al2O3-13%TiO2(质量分数,下同)涂层的直接熔覆实验。利用光学显微镜(OM)和电子探针显微分析仪(EMPA)分析单道熔覆试样的互熔稀释特征、显微组织及成分分布情况。结果表明:熔覆过程容易形成熔覆道边缘以陶瓷对基体的稀释为主,而中部以重熔基体对陶瓷层的稀释为主的互熔稀释区(DZ);DZ区中部重熔金属内分布有较多的陶瓷颗粒,且陶瓷颗粒聚集处容易产生裂纹。采用单因素法优化工艺参数控制互熔稀释区的大小,可以获得互熔稀释较弱、无明显裂纹的Al2O3-13%TiO2陶瓷熔覆试样。

The direct cladding of Al2O3-13wt%TiO2 coating on Ti-6Al-4V alloy substrate was performed with coaxial laser cladding. OM and EMPA were used to examine the dilution characters, microstructure and element distribution of the cross-sections of cladding samples. The results show that after the irradiation the dilution zone （DZ） is likely to form the distinct pattern that at the edges of single clad pass the ceramic coating penetrates into the substrate, while in the middle of the pass the melting metal protrudes from the substrate into the ceramic coating. Moreover, there are many ceramic particles distributing in the DZ zone, and the layer is prone to produce more cracks with the cluster formation of the ceramic particles. The coating with low dilution and no obvious cracks is obtained by optimizing the processing parameters.