在不同工艺参数下, 在球墨铸铁QT450-10表面激光熔覆了镍基合金, 分析了熔覆层的显微组织和物相组成, 研究了熔覆前、后试样的拉伸应力-应变曲线及试样的断口形貌。结果表明, 当激光功率为1.6 kW、激光扫描速率为400 mm·min-1、送粉速率为3.2 r·min-1时, 熔覆结果较好, 基体与熔覆层间形成了良好的冶金结合, 无裂纹、气孔; 在25 ℃下, 当熔覆层数为1时, 熔覆层的显微硬度达到265 HV, 约为基体硬度的1.5倍; 熔覆后试样的断裂部位在基体处, 熔覆镍基合金的球墨铸铁的强度得到提高。

Under different process parameters, the laser cladding of Ni-based alloys on the spheroidal graphite cast iron QT450-10 surface is conducted, the microstructure and the phase compositions of cladding layers are analyzed, and the tensile stress-strain curves of samples with and without laser cladding and the fracture morphologies of samples are studied. The results show that, when the laser power is 1.6 kW, the laser scanning speed is 400 mm·min-1 and the powder feeding speed is 3.2 r·min-1, better quality cladding layer can be achieved and a good metallurgical bonding is formed between the matrix and the cladding layer where no cracks and pores are observed. Under the temperature of 25 ℃ and when the cladding layer number is 1, the microhardness of cladding layers is 265 HV, about 1.5 times of that of the matrix. The fracture site of cladding samples is in the matrix. After the laser cladding of Ni-based alloys, the strength of the spheroidal graphite cast iron is enhanced.