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利用CO2激光宽带熔覆技术在45钢表面制备了添加纳米WC/Co-N i基、WC/Co-Fe基熔覆层。用SEM、EDS、XRD进行观察和分析,对比研究了添加纳米WC/Co-N i基、WC/Co-Fe基熔覆层的形貌、组织结构、强化相的形状及其分布。结果表明,N i基熔覆层中物相主要为黑色(Fe,N i)、B2Fe3N i3基体上分布着WC、Cr2Fe14C等白色的碳化物相,而Fe基熔覆层中的白色碳化物相中有W2C、Fe3W3C。在优化的工艺参数下,通过连续控制微观结构要素,可以实现成分、组织的变化,获得无气孔、无裂纹的熔覆层。采用EVANS压痕法测得喷焊N i基WC/Co复合陶瓷涂层断裂韧度KIC的平均值为9 MN.m-3/2,而在现有维氏硬度计最大载荷50 kg的情况下,激光熔覆添加纳米WC/Co合金粉末涂层得到的熔覆层仍无裂纹出现,证实了激光熔覆添加纳米WC/Co合金粉末涂层的抗裂作用。
The WC / Co-Ni-based WC / Co-Fe-based cladding layer was prepared on the surface of 45 steel by CO2 laser cladding. SEM, EDS and XRD were used to observe and analyze the morphology, microstructure and shape and distribution of WC / Co-Ni-based and WC / Co-Fe based coatings. The results show that the phase of the Ni-based cladding layer is mainly black (Fe, Ni), the white carbide phase of WC, Cr2Fe14C is distributed on the B2Fe3Ni3 matrix, whereas the white carbide phase in the Fe-based cladding layer There are W2C, Fe3W3C. Under optimized process parameters, the microstructure elements can be continuously controlled to realize the change of composition and structure, and the non-porous and crack-free cladding layer can be obtained. The average value of fracture toughness KIC of spray-welded Ni-based WC / Co composite ceramic coating measured by EVANS indentation method is 9 MN.m -3/2, whereas in the case of the existing Vickers hardness maximum load 50 kg , The cladding layer obtained by laser cladding with nano-WC / Co alloy powder coating is still free of cracks, which confirms the anti-cracking effect of the laser cladding nano-WC / Co alloy powder coating.