Supersaturated W-Cu nanocomposites with outstanding strength-ductility synergy

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2023-05, Vol.874, p.144578, Article 144578
• Main Authors: Zhang, Hongbo, Liu, Tao, Han, Yong, Lu, Yaozha, Zhao, Siqi, Tian, Jiamin, Tang, Sisi, Xu, Zhanyuan, Lu, Qiong, Fan, Jinglian
• Format: Article
• Language: English
• Subjects: Immiscible system; Nano-twins; Supersaturated solid solution; Tensile properties; W-Cu Nanocomposites
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2023.144578

Alloying immiscible elements has great scientific and engineering significance for materials discovery and property tailoring. However, achieving alloying in bulk state remains enormous challenge due to the strong immiscibility of them. Here, for the most classic immiscible W-Cu system, a supersaturation strategy is proposed to increase the solubility between W and Cu into a previously unattainable region where nanoscale W(Cu) supersaturated solid solution (SSS) is in-situ formed in matrix. According to the direct observation of spherical-aberration transmission electron microscopy (STEM) together with atomic-resolution chemical mapping, W(Cu) SSS is a chemical-random solid solution with bcc structure, which is composed of about 20% Cu atoms randomly replacing W atoms in W lattice. The distribution of Cu elements in SSS is heterogeneous, which tends to form nanoclusters with 10 nm in size. In addition, we elucidate the effect of SSS on mechanical properties and deformation mechanisms of W-Cu nanocomposite. Achieved strength-ductility synergy originates from the mediation of dislocations and polymorphic nano-twins. This study enriches the understanding of SSS and provides a general approach to fabricating nanocomposites with excellent mechanical properties between immiscible elements. •Bulk W-Cu nanocomposites with W(Cu) supersaturated solid solution (SSS) phase were prepared via supersaturation strategy.•The structure and chemical composition of SSS were revealed at the atomic scale. SSS is a chemically disordered substitutional solid solution formed by about 20% of Cu atoms replacing W atoms in the W lattice. Cu elements are heterogeneously distributed in SSS, which tends to form nanoclusters of about 10 nm in size at the nanoscale.•The supersaturated W-Cu nanocomposites have an exceptional combination of tensile strength and ductility, and their excellent mechanical properties come from the mediation of dislocations and polymorphic nano-twins (including 9R phase).