为了提高同轴送粉激光熔化沉积技术AlSi10Mg铝合金成形质量，本文通过单道扫描试验、块体成形试验和拉伸性能测试研究不同工艺参数下试样致密度、组织和性能变化趋势和原因，并进行优化。结果表明，试样成形质量受能量密度和扫描间距影响，拉伸性能通过减少组织缺陷、增强固溶强化效果两种方式提高。工艺优化后，单道表面光滑，无球化现象，块体试样致密度良好，无大尺寸孔隙和裂纹，致密度提高至99.2%；试样显微组织为具有定向快速凝固特征的Al-Si共晶形貌，存在胞晶、柱状树枝晶和发散树枝晶三种组织，随着冷却速率的增大，Si相在Al基体中的溶解度增加至7.6%，固溶强化效果增强。因此通过工艺参数优化可得到性能良好的激光熔化沉积AlSi10Mg试样，拉伸强度可达292MPa，较铸件提高33%。

In order to improve the manufacturing quality of the AlSi10Mg aluminum alloy fabricated by Laser Melting Deposition based on coaxial powder feeding, this paper carried out the single tracks test, block samples forming experiments and tensile property test to investigate the variation trend on the microstructure and property under different process parameters. The experimental results showed that the manufacturing quality of the LMD processed samples was significantly governed by energy density of laser beam and the hatch spacing. tensile property was improved by decreasing the level of porosity and enhancing the effect of solid solution strengthening. After process optimization, the morphology of the single tracks was smooth without spheroidization. The relative density of the block samples was increased to 99.2% without larger pores and cracks. The microstructure of samples had directional rapid solidification characteristics with Al-Si eutectic microstructure contained three microstructures of cellular crystal, columnar dendritic crystal and divergent dendrite crystal. With the increase of cooling rate, the solubility of Si phase in Al matrix was increased to 7.6%. The effect of solid solution strengthening was enhanced. Therefore, AlSi10Mg samples fabricated by laser melting deposition with good performance could be obtained by optimizing the process parameters. The tensile stress of the samples was 292MPa, which was 33% higher than that of the cast samples.