铝合金密度低、比强度高、耐腐蚀性能好，是一种优异的轻量化金属材料。为了提升激光选区熔化（SLM）技术成形铝合金的力学性能，提出将Cu元素作为单质颗粒掺入铝合金材料的强化方法，探究了Cu元素掺入比例对SLM成形铝合金打印质量和性能的影响。结果表明，Cu粉的掺入简单有效地细化了铝合金显微组织晶粒，提高了基础铝合金材料的拉伸强度。Al₂Cu相能有效细化晶粒，在搭接区域形成更细密的微观等轴晶组织。随着铜粉掺入量的增大，组织内部生成的Al₂Cu相逐渐增加，晶粒尺寸逐渐减小，从3.30 μm减小至2.12 μm，显微组织得到了细化。掺入质量分数5%铜粉的样件具有最高的拉伸强度为460 MPa，较未添加样件提高了20.4%，但是过量铜粉掺入后，样件内部因为存在未熔颗粒性能有一定程度的下降。该研究对于进一步提高SLM成形铝合金的力学性能具有重要意义。

Aluminum alloy is an excellent lightweight metal material with low density, high specific strength, and good corrosion resistance. In order to improve the mechanical properties of aluminum alloy fabricated by laser selective melting (SLM), this paper proposed a strengthening method of aluminum alloy material in which Cu element was used as simple particle, and explored the influence of the proportion of Cu element on the forming quality and properties of aluminum alloy fabricated by SLM. The results showed that the doping of Cu powder can refine the microstructure grain of aluminum alloy simply and effectively, and improved the tensile strength of aluminum alloy material. Al₂Cu phase could effectively refine the grain and form a more compact micro equiaxed crystal structure in the overlapping area. With the increase of the content of copper powder, the Al₂Cu phase generated in the structure gradually increased, and the grain size gradually decreased from 3.30 μm to 2.12 μm. The microstructure was refined. The sample containing 5% copper powder had the highest tensile strength of 460 MPa, which was 20.4% higher than that without copper powder. However, after excessive copper powder was dopped, the performance of the sample was reduced to a certain extent due to the presence of un-melted particles. This study is of great significance to further improve the mechanical properties of aluminum alloy fabricated by SLM.