比能量对激光熔覆Ni60组织及力学性能的影响

Effect of Specific Energy on Microstructure and Mechanical Properties of Ni60 by Laser Cladding

采用激光熔覆Ni60合金粉末在42CrMo钢板上制备镍基复合涂层,并对熔覆层的表面形貌、微观组织、物相、维氏硬度、耐磨性及剪切强度进行了分析,同时分析了激光功率和扫描速度对激光熔覆层组织和摩擦磨损性能的综合影响。结果表明:不同比能量下各Ni60熔覆层物相种类一致,比能量过高或过低其熔覆层表面均会产生较大飞溅或烧蚀;其显微硬度与基体相比提高了约1.4~1.96倍,随着比能量的降低其硬度逐渐增加,而摩擦系数及磨损量随比能量的降低逐渐减小;熔覆层具有较高的抗剪强度,可达到225~259 MPa;当比能量为4.8 kJ/cm2时熔覆层表面飞溅小、鱼鳞纹排列紧密且厚度均匀,同时组织致密、力学性能优异且熔覆层与基体达到了良好的冶金结合。

A nickel⁃based composite coating was prepared on 42CrMo steel plate using laser melting of Ni60 alloy powder.The comprehensive effects of laser power and scanning speed on the microstructure and friction wear properties of the laser clad layer were investigated.The surface morphology,microstructure,physical phase,vickers hardness,wear resistance and shear strength of the cladding layer were also analyzed.The results show that the Ni60 clad layer has the same physical phase at different specific energies,and the surface of the cladding layer will produce large spattering or ablation when the energy is too high or too low.The microhardness is significantly higher than that of the substrate,about 1.4~1.96 times that of the substrate,and gradually increases with the decrease of specific energy,while the friction coefficient and wear amount gradually decrease with the decrease of specific energy.The cladding layer has high shear strength,which can reach 225~259 MPa.When the specific energy is 4.8 kJ/cm2,the surface splash of the clad layer is small,the fish scale pattern is closely arranged and the thickness is uniform,the microstructure is dense.The mechanical properties are excellent and the clad layer achieves a good metallurgical bond with the substrate.