中文摘要：

应用激光熔覆法，采用镍基NiCrSiB粉末，在20^#钢表面制备了熔覆涂层，并用激光重熔涂层。观察了熔覆-重熔层的形貌，检测了其相组成和高温耐磨性能，结果表明：所制得熔覆-重熔层组织均一、致密，与基体形成了良好的冶金结合；经重熔处理后，熔覆层表面的裂纹显著减少；熔覆-重熔层的硬度提高到基体的5倍，高温磨损率约为基体的1／3。熔覆-重熔层耐磨能力的增强除因其与基体形成了良好的冶金结合和硼化物、硼碳化物等析出相的强化作用外，也是重熔减少微裂纹的结果。

英文摘要：

Ni-based alloy laser cladding layer and laser cladding-remelting layer were made on surface of 20 steel specimens using NiCrSiB powder. Phase characteristics, high temperature abrasive-wear behavior and surface morphologies after abrasive-wearing of the layers were investigated and the results show that laser cladding-remelting layer has dense microstructure, and has metallurgical combination with 20 steel substrate. There is much less cracks in laser cladding-remelting layer after remelting process. Micro-hardness and high temperature abrasive-wearing resistance of laser cladding layer are 5 and 3 times of 20 steel specimen separately. The improvement in high temperature abrasive wearing resistance of the layer is due to the metallurgical combination; Strengthen effects of borides and boron carbides precipitate phases and less harmful cracks.