Abstract Nanostructured Cu–Ta alloys show great potential as high strength nanocrystalline materials due to their excellent mechanical properties and limited grain growth at high temperatures. This report describes the fabrication of nanostructured immiscible Cu–Ta alloys in bulk by high-pressure torsion (HPT) using a stack of Cu/Ta/Cu discs at room temperature. A microstructural study after HPT processing showed that the internal Ta layer breaks into small individual flakes which distribute uniformly over the Cu matrix through increases in the numbers of HPT turns. There is solid-state diffusion between the Cu and Ta when the HPT processing increases to 100 turns due to microstructural refinement and increasing crystalline defects. After processing through 150 turns, a composite microstructure of two phases is formed including supersaturated Cu–Ta solid solutions (Cu81Ta19 and Ta78Cu22 alloys) with a crystallite size of ∼35–45 nm. This fine microstructure produces exceptional mechanical properties including a high hardness of over 350 Hv corresponding to ∼3.43 GPa, a tensile strength of ∼1300 MPa and a tensile elongation of about 40%.

中文翻译：

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高压扭转加工纳米结构不混溶Cu-Ta合金的制备和表征

摘要 纳米结构的 Cu-Ta 合金由于其优异的机械性能和在高温下有限的晶粒生长，作为高强度纳米晶材料显示出巨大的潜力。本报告描述了在室温下使用一堆 Cu/Ta/Cu 盘通过高压扭转 (HPT) 批量制造纳米结构的不混溶 Cu-Ta 合金。HPT 处理后的显微结构研究表明，随着 HPT 匝数的增加，内部 Ta 层分解成小的单个薄片，这些薄片均匀分布在 Cu 基体上。由于微观结构细化和晶体缺陷增加，当 HPT 加工增加到 100 圈时，Cu 和 Ta 之间存在固态扩散。经过 150 圈加工后，形成了两相的复合微观结构，包括微晶尺寸约为 35-45 nm 的过饱和 Cu-Ta 固溶体（Cu81Ta19 和 Ta78Cu22 合金）。这种精细的微观结构产生了卓越的机械性能，包括超过 350 Hv 的高硬度，对应于~3.43 GPa，拉伸强度为~1300 MPa，拉伸伸长率约为 40%。