This study examined the impact of the Al/Sc atomic ratio on the electrical conductivity, mechanical properties, and thermal stability of pure copper. By regulating the Al/Sc atomic ratio within the range of 1 to 3, the microstructure of the alloy was characterized via OM, EBSD, and TEM, among other methods. The results demonstrated that when the Al/Sc atomic ratio was approximately 3, the overall performance of the alloy was the most favorable. After a series of processing treatments, the conductivity, hardness and tensile strength in the cold-rolled state are 87.2% IACS, 145 HV and 396 MPa respectively, and the softening temperature is approximately 510°C. After being treated at 850°C for 30 minutes, the conductivity increases to 95.6% IACS, the hardness decreases to 57.4 HV, and the average grain size is 72.92μm. When the atomic ratio of Al/Sc is approximately 3:1, under high-temperature conditions, Sc atoms almost entirely take part in the formation of oxide precipitation phases (such as Al₂O₃ and AlScO₃), preventing the formation of excessive Sc solid solution or coarse phases (such as AlSc₂). Furthermore, a large quantity of spherical Al₂O₃ precipitated phases with a size of approximately 6.9 nm, which are dispersed within the grain boundaries, have been formed. These small-sized particles offer a high density of pinning points. Simultaneously, ellipsoidal AlScO₃ precipitated phases with a size of approximately 18 nm have been formed on the grain boundaries,The larger particles can effectively stabilize the grain boundaries and inhibit their migration rate under high temperatures, thereby significantly improving the strength and thermal stability of the alloy.

中文翻译：

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Al/Sc 原子比对纯铜导电性、力学性能和热稳定性的影响

本研究研究了 Al/Sc 原子比对纯铜的电导率、机械性能和热稳定性的影响。通过在 1 到 3 的范围内调节 Al/Sc 原子比，通过 OM、EBSD 和 TEM 等方法表征了合金的微观组织。结果表明，当 Al/Sc 原子比约为 3 时，合金的整体性能最有利。经过一系列加工处理后，冷轧状态下的导电率、硬度和抗拉强度分别为 87.2% IACS、145 HV 和 396 MPa，软化温度约为 510°C。 在 850°C 下处理 30 分钟后，电导率增加到 95.6% IACS，硬度降低到 57.4 HV，平均晶粒尺寸为 72.92μm。当 Al/Sc 的原子比约为 3：1 时，在高温条件下，Sc 原子几乎完全参与氧化物沉淀相（如 Al ₂ O ₃ 和 AlScO ₃ ）的形成，防止形成过量的 Sc 固溶体或粗相（如 AlSc ₂ ）。此外，还形成了大量分散在晶界内的尺寸约为 6.9 nm 的球形 Al ₂ O ₃ 沉淀相。这些小颗粒提供了高密度的固定点。同时，在晶界上形成了尺寸约为 18 nm 的椭球形 AlScO ₃ 析出相，较大的颗粒在高温下可以有效稳定晶界并抑制其迁移速率，从而显著提高合金的强度和热稳定性。