Abstract Initially micrometer-sized powder blends of different compositions (Cu-6at%Ag, Cu-37 at%Ag and Cu-84 at%Ag corresponding to Cu-9vol%Ag, Cu-46 vol%Ag and Cu-89 vol%Ag) were deformed by high-pressure torsion for varying applied strain and temperature in order to study their effect on the degree of supersaturation and the prevailing deformation mechanisms. The resulting microstructures were comprehensively characterized with synchrotron X-ray diffraction and transmission electron microscopy. A gradual transition from complete supersaturation to complete phase separation was observed with increasing processing temperature. The critical temperature for full supersaturation strongly depended on the composition. In composites with low Ag and Cu contents single-phase alloys could be obtained up to processing temperatures of 100 °C. In the medium composition range strain localization in shear bands prevented full supersaturation for room temperature deformation. Only in regions deformed by shear bands a complete single-phase supersaturated solid solution was obtained, while the lamellar matrix retained a dual-phase structure. By lowering the processing temperature, using liquid nitrogen as coolant, a homogenous single-phase alloy could be also attained at medium compositions. The present results unravel a clear correlation between dominating deformation mechanisms and the degree of deformation-induced supersaturation.

中文翻译：

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加工温度对Cu-Ag纳米复合材料微观结构特征的影响：从过饱和到完全相分解

摘要 最初是不同成分的微米级粉末混合物（Cu-6at%Ag、Cu-37 at%Ag 和 Cu-84 at%Ag 对应于 Cu-9vol%Ag、Cu-46 vol%Ag 和 Cu-89 vol% Ag）通过高压扭转变形以改变施加的应变和温度，以研究它们对过饱和度和主要变形机制的影响。用同步加速器 X 射线衍射和透射电子显微镜对所得微结构进行了全面表征。随着加工温度的升高，观察到从完全过饱和到完全相分离的逐渐转变。完全过饱和的临界温度很大程度上取决于组成。在具有低 Ag 和 Cu 含量的复合材料中，可在高达 100 °C 的加工温度下获得单相合金。在中等成分范围内，剪切带中的应变局部化防止了室温变形的完全过饱和。只有在剪切带变形的区域才能获得完整的单相过饱和固溶体，而层状基质保持双相结构。通过降低加工温度，使用液氮作为冷却剂，还可以获得中等成分的均质单相合金。目前的结果揭示了主要变形机制与变形引起的过饱和程度之间的明显相关性。而层状基质保留了双相结构。通过降低加工温度，使用液氮作为冷却剂，还可以获得中等成分的均质单相合金。目前的结果揭示了主要变形机制与变形引起的过饱和程度之间的明显相关性。而层状基质保留了双相结构。通过降低加工温度，使用液氮作为冷却剂，还可以获得中等成分的均质单相合金。目前的结果揭示了主要变形机制与变形引起的过饱和程度之间的明显相关性。