To enhance the high-temperature performance of 205 A aluminum alloy produced via Wire Arc Directed Energy Deposition (WA-DED), Ni was selected as the primary alloying element. Both 205 A and 205 A(Ni) aluminum alloys were fabricated via WA-DED, and their microstructures and high-temperature mechanical properties were comparatively analyzed. The results indicated the successful fabrication of thin-walled components of both alloys using WA-DED technology. Microstructural analysis revealed that both alloys predominantly consisted of equiaxed crystals, with some columnar crystals observed. After T6 heat treatment, the grains of 205 A (Ni) exhibit better stability. Notably, 205 A(Ni) formed the high-temperature heat-resistant phase γ(Al₇Cu₄Ni) during solidification. This phase did remain stable under high-temperature conditions and effectively inhibited grain boundary migration and growth, thereby significantly enhancing the high-temperature performance of the alloy. At a service temperature of 200°C, the transverse and longitudinal ultimate tensile strengths (UTS) of the WA-DED-produced 205 A(Ni) alloy were 331 MPa and 335 MPa, which represented increases of 27 MPa and 40 MPa, respectively, compared with the 205 A alloy.

中文翻译：

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通过添加镍元素增强 WA-DED 205 A 铝合金的高温性能

为了提高通过线弧定向能量沉积 （WA-DED） 生产的 205 A 铝合金的高温性能，选择 Ni 作为主要合金元素。通过 WA-DED 制备了 205 A 和 205 A（Ni） 铝合金，并对其微观组织和高温力学性能进行了比较分析。结果表明，使用 WA-DED 技术成功制造了两种合金的薄壁部件。微观结构分析表明，两种合金主要由等轴晶体组成，并观察到一些柱状晶体。经过 T6 热处理后，205 A （Ni） 的晶粒表现出更好的稳定性。值得注意的是，205 A（Ni） 在凝固过程中形成了高温耐热相 γ（Al ₇ Cu ₄ Ni）。该相在高温条件下保持稳定，有效抑制了晶界迁移和生长，从而显著提高了合金的高温性能。在 200°C 的使用温度下，WA-DED 生产的 205 A（Ni） 合金的横向和纵向极限拉伸强度 （UTS） 分别为 331 MPa 和 335 MPa，与 205 A 合金相比，分别增加了 27 MPa 和 40 MPa。