镍基非晶复合涂层激光制备及其纳米压痕测试

采用大功率半导体激光熔覆和重熔的工艺在低碳钢表面制备Ni-Fe-B-Si-Nb合金非晶复合涂层，并对所得涂层进行了纳米压痕性能测试。研究结果表明，当激光熔覆时激光功率为0.8 kW，熔覆速度为0.36 m/min，送粉速度为12 g/min，重熔时激光功率为3.5 kW，熔覆速度为8 m/min，在低碳钢表面成功制备了Ni40.8Fe27.2B18Si10Nb4非晶复合涂层，涂层主要由非晶相和NbC颗粒相组成。纳米压痕测试结果表明经激光重熔后所得非晶复合涂层的显微硬度和弹性模量远远大于未重熔的熔覆层，并且也大于同成分大块非晶。

Fabrication of Ni-based amorphous composite coating using laser processing and its nano-indentation test

Ni-Fe-B-Si-Nb amorphous composite coating was fabricated using laser cladding plus laser remelting process using high powder diode laser on mild steel surface. The phase and microstructure of the coating were studied using X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The mechanical properties of the coating were studied by nano-indentation tests. The results showed that Ni40.8Fe27.2B18Si10Nb4 amorphous composite coating was obtained when the laser cladding power was 0.8 kW, the scanning speed was 0.36 m/min, the powder feed rate was 12g/min, the laser remelting power was 3.5 kW and the scanning speed was 8 m/min. It was found that the laser remelting coatings exhibited dense amorphous structure matrix embedded by some crystal phases((Fe,Ni) and NbC). Nano-indentation test results indicated that the microhardness and elastic modulus of the remelting coating were far higher than that of the laser cladded coating, and they were also higher than that of BMGs with the same nominal compositions. The average microhardness and elastic modulus of the laser remelting coating were 1 227.9 HV and 277.4 GPa, respectively.