研究热处理对电弧定向能量沉积Al-Zn-Mg-Cu-Sc合金显微组织与力学性能的影响，对于优化该合金增材制造工艺、提升其综合性能具有重要意义。本工作以自制7075-Sc焊丝为原材料，采用冷金属过渡(CMT)工艺制备了无裂纹的Al-Zn-Mg-Cu-Sc厚壁合金构件。结果表明，沉积态合金由细小的等轴晶组成，平均尺寸约14 μm，晶界有连续第二相分布。在470 ℃、4 h的固溶工艺下，第二相溶解70.2%，残余第二相主要为Al₇Cu₂Fe和Al₂Mg₃Zn₃。在120 ℃进行人工时效后，力学性能测试结果表明最佳时效时间为18 h。经过470 ℃、4 h固溶和120 ℃、18 h时效处理后，合金的屈服强度、抗拉强度、伸长率分别为475.2 MPa、542.1 MPa和5.2%，与沉积态合金相比分别提高了52.8%、36.5%和36.8%。

Wire-arc directed energy deposition (DED) shows considerable potential for fabricating structural components from Al-Zn-Mg-Cu-Sc alloys. However, its layer-by-layer deposition nature leads to continuous grain boundary second-phase networks, grain coarsening, elemental microsegregation, and residual stress accumulation during solidification of 7075-Sc aluminum alloys, significantly compromising their mechanical properties and industrial viability. As a precipitation-strengthened alloy, 7075 can be optimized through heat treatment to control the morphology and distribution of secondary phases, thereby improving mechanical performance. Nevertheless, the inhomogeneous as-deposited microstructure proves difficult to fully homogenize using conventional heat treatment, necessitating precise temperature control and tailored aging schedules for effective thermal processing. In this study, crack-free, thick-walled Al-Zn-Mg-Cu-Sc alloy components were fabricated using custom 7075-Sc welding wire and the cold metal transfer process. Microstructural analysis revealed that the as-deposited alloy consists of fine equiaxed grains with an average diameter of approximately 14 μm and a continuous grain boundary second-phase distribution. Solution treatment at 470 ^oC results in a markedly reduced dissolution rate of the secondary phases over time, with a 4 h duration identified as optimal. Under this condition, 70.2% of the secondary phases are dissolved; the remaining phases are predominantly Al₇Cu₂Fe and Al₂Mg₃Zn₃. Subsequent artificial aging at 120 ^oC showed that an aging time of 18 h yields optimal mechanical properties. Following the combined solution and aging treatments, the alloy exhibited a yield strength of 475.2 MPa, tensile strength of 542.1 MPa, and elongation of 5.2%. These values represent increases of 52.8%, 36.5%, and 36.8%, respectively, compared to the as-deposited alloy.