Employing a single strategy that overcomes the strength-ductility-conductivity trade-off in copper alloys has proven to be challenging. In this study, we introduced a novel heterogeneous nanoprecipitate–dislocation (HND) architecture in CuCrNb alloy consisting of a multi-modal core–shell grain structure and an interconnected dislocation network pinned by abundant nanoprecipitates. Our CuCrNb-HND alloy exhibited superior strength–ductility synergy at both room and elevated temperatures. In particular, aging treatment-induced high-density coherent Cr secondary nanoprecipitates into the HND skeleton endowed the CuCrNb-HND450 alloy with a high tensile strength of over 1 GPa and a conductivity of ∼50%, surpassing those of most of the reported additively manufactured copper alloys. An transmission electron microscopy heating experiment revealed the superior thermal stability of the HND architecture. Hierarchical strengthening contributed to the enhancement of mechanical properties. At the micrometer scale, the harmonic grain structure with a strong fine-grained shell and a ductile coarse-grained core effectively improved mechanical properties by suppressing localized plastic deformation. At the nanometer scale, the synergistic effect of the nanoprecipitate–dislocation network further improved the alloy strength by slowing down dislocation movement. Overall, our proposed HND architecture provides an efficient pathway for developing high-strength and high-conductivity copper alloys.

中文翻译：

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增材制造的铜合金具有异质纳米沉淀-位错结构，可实现卓越的强度-延展性-电导率协同作用

事实证明，采用单一策略来克服铜合金的强度-延展性-导电性权衡是具有挑战性的。在这项研究中，我们在 CuCrNb 合金中引入了一种新型异质纳米沉淀-位错 (HND) 结构，该结构由多模态核壳晶粒结构和由丰富的纳米沉淀物固定的互连位错网络组成。我们的 CuCrNb-HND 合金在室温和高温下均表现出卓越的强度-延展性协同作用。特别是，时效处理诱导的高密度共格 Cr 二次纳米沉淀物进入 HND 骨架，赋予 CuCrNb-HND450 合金超过 1 GPa 的高拉伸强度和~50% 的电导率，超过了大多数报道的增材制造的合金。铜合金。透射电子显微镜加热实验揭示了 HND 结构卓越的热稳定性。分级强化有助于提高机械性能。在微米尺度上，具有坚固的细晶壳和延性粗晶核的调和晶粒结构通过抑制局部塑性变形有效地提高了机械性能。在纳米尺度上，纳米沉淀物-位错网络的协同效应通过减慢位错运动进一步提高了合金强度。总的来说，我们提出的 HND 架构为开发高强度和高导电率的铜合金提供了一条有效的途径。