针对灰铸铁激光熔覆的白口组织和开裂问题，研究了NiCuFeBSi合金材料及基体预热工艺对白口组织控制的影响，评价了合金力学性能。结果表明，NiCuFeBSi合金熔覆层界面白口组织宽度较小，基体预热温度升高时，白口组织呈现分散、断续状分布。半熔化区由于白口组织存在，显微硬度在此区达到峰值，向界面两侧呈递减趋势；NiCuFeBSi合金抗拉强度较高，横向抗拉强度大于纵向，其与HT250的对接试样抗拉强度受热影响区强度下降影响，强度小于NiCuFeBSi合金和HT250。熔覆层拉伸断裂机制为解理断裂为主、解理与准解理混合型断裂。

Due to existence of chill microstructure and cracks, influence of flaw control with laser cladding NiCuFeBSi alloy and preheating are investigated. Mechanical property of alloy is estimated as well. Results show that chill microstructure width of NiCuFeBSi alloy is extremely low. With preheating temperature increasing, the chill microstructure become discontinuous. Because of the generation of chill microstructure in semi-molten zone, microhardness in this zone is highest while descending at two sides of interface. Tensile strength of alloy is higher than HT250, furthermore, tensile strength along cross direction is higher than longitudinal direction. However, tensile strength of butt samples is lowest because of heat affection. Failure type of claddings is mainly cleavage fracture mixing quasi-cleavage fracture.