本文利用大功率CO_2连续式激光器,研究了Al-12.7％S_1共晶合金表面快速熔凝处理的组织与性能。试验结果表明,激光功率密度与激光扫描速度,对Al-Si合金表面熔凝层的组织细化具有重要作用。在快速熔凝条件下,其熔凝表层为极细的α+(α+Si)亚共晶组织,次表层为具有方向性分布的柱状树枝晶组织。由于表层组织的细化,使其显微硬度得到明显提高(由HV50→HV90),而耐磨性与未经处理的铸态组织相比、可提高一倍以上。 In this paper, the use of high-power CO_2 continuous laser, the Al-12.7% S 1 eutectic alloy surface rapid solidification of the microstructure and properties. The experimental results show that laser power density and laser scanning speed play an important role on the microstructure refinement of Al-Si alloy. Under the condition of rapid solidification, the fused surface layer is a very fine α + (α + Si) hypoeutectic structure, and the subsurface layer is a columnar dendritic structure with directional distribution. Due to the thinning of the surface structure, the microhardness is obviously improved (from HV50 to HV90), and the wear resistance can be more than doubled compared with the untreated as-cast structure.