Abstract Multi-modal precipitate distribution in the microstructure, with coarse precipitates pinning the grain boundaries and finer precipitates strengthening the matrix, is beneficial to suppress grain boundary sliding and dislocation creep, respectively, of structural materials. However, achievement of a multi-modal precipitate distribution remains a challenge in developing creep-resistant advanced Cu alloys while retaining high strength and high conductivity at elevated temperature. This work overcame this challenge with the aid of computational thermodynamics. Thermodynamic models for Gibbs energy functions of phases in the Cu-Cr-Nb-Zr system have been developed in this study. These models were then used to calculate solidification paths and phase equilibria at different temperatures, guiding the design of chemical composition and heat treatment parameters of novel copper alloys with a target multi-modal distribution of precipitates. The new alloy, fabricated through traditional ingot metallurgy method, has achieved the desired microstructure as validated by optical and transmission electron microscopy. Electrical conductivity and mechanical properties were screened and compared with the existing commercial Cu alloys.

中文翻译：

---

借助计算热力学开发新型 Cu-Cr-Nb-Zr 合金

摘要 显微组织中的多模态析出物分布，粗大析出物钉扎晶界，细小析出物强化基体，分别有利于抑制结构材料的晶界滑移和位错蠕变。然而，在开发抗蠕变的高级铜合金同时在高温下保持高强度和高导电性方面，实现多模式沉淀分布仍然是一个挑战。这项工作借助计算热力学克服了这一挑战。在这项研究中，已经建立了 Cu-Cr-Nb-Zr 系统中相的 Gibbs 能量函数的热力学模型。然后使用这些模型计算不同温度下的凝固路径和相平衡，指导具有目标多模态析出物分布的新型铜合金的化学成分和热处理参数的设计。通过传统的铸锭冶金方法制造的新合金已达到所需的微观结构，经光学和透射电子显微镜验证。筛选导电性和机械性能，并与现有的商业铜合金进行比较。