The microstructural evolution and hardness and physical properties of a Cu-Hf alloy at the different processing stages were investigated using hardness, conductivity and tensile measurements, metallographic microscopy, scanning electron microscopy, and transmission electron microscopy. The results reveal that the electrical conductivity of these alloys was above 80% IACS after aging at 450°C, and the hardness and conductivity of the Cu-0.9Hf alloy were 180 HV0.5 and 80% IACS, respectively. The softening temperature of the Cu-0.15Hf alloy is 525°C, and the softening temperature of Cu-0.4Hf and Cu-0.9Hf alloys is 550°C. The precipitated Hf-containing phase exhibited a short rod-like structure, the size of which increased with aging time at a slow rate and resulted in the size of ~20 nm after aging at 450°C for 300 min.

中文翻译：

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Cu-Hf合金在不同加工阶段的物理性质和析出物显微组织

使用硬度、电导率和拉伸测量、金相显微镜、扫描电子显微镜和透射电子显微镜研究了 Cu-Hf 合金在不同加工阶段的显微组织演变、硬度和物理性能。结果表明，这些合金在450℃时效后电导率均在80% IACS以上，Cu-0.9Hf合金的硬度和电导率分别为180 HV0.5和80% IACS。Cu-0.15Hf合金的软化温度为525℃，Cu-0.4Hf和Cu-0.9Hf合金的软化温度为550℃。析出的含 Hf 相呈现出短棒状结构，其尺寸随老化时间缓慢增加，在 450°C 老化 300 分钟后尺寸约为 20 nm。