论文标题
通过动态应变老化，CU/NB纳米胺的高温强度保持
High temperature strength retention of Cu/Nb nanolaminates through dynamic strain ageing
论文作者
论文摘要
通过从室温到400的微柱压缩测试进行了Cu/Nb金属纳米酰胺的机械性能（7、16、34和63 nm）的机械性能（7、16、34和63 nm）。伴随着应变速率敏感性为0，在200 c时高强度保持量，以及在纳米酰胺中NB层沿NB层发生的低菌株（5％-6％）变形的剪切定位的发展。变形标本的原子探针断层扫描揭示了NB层中实心溶液中O的存在，但在CU层中不存在O。因此，发现O原子向NB中的移动位错扩散是CU/NB纳米胺中动态应变衰老的起源。由于在较高的温度（400 C）下未发现这种机制，因为变形主要由Cu层中应力辅助扩散控制。这一发现显示了一种新的策略，以通过一个相的动态应变老化在金属纳米酰胺的高温下增强强度的保留率。
The mechanical properties of Cu/Nb metallic nanolaminates with different layer thickness (7, 16, 34 and 63 nm) were studied by means of micropillar compression tests from room temperature to 400 C. Both strain-rate jump and constant strain rate tests were carried out and they showed evidence of dynamic strain ageing in the nanolaminates with 7, 16 and 34 nm layer thickness deformed at 200 C. Dynamic strain ageing was accompanied by a reduction of the strain rate sensitivity to 0, high strength retention at 200 C and the development of shear localization of the deformation at low strains (5%-6%) that took place along the Nb layers in the nanolaminates. Atom probe tomography of the deformed specimens revealed the presence of O in solid solution in the Nb layers but not in the Cu layers. Thus, diffusion of O atoms to the mobile dislocations in Nb was found to be the origin of the dynamic strain ageing in the Cu/Nb nanolaminates around 200 C. This mechanism was not found at higher temperatures (400 C) because deformation was mainly controlled by stress-assisted diffusion in the Cu layers. This discovery shows a novel strategy to enhance the strength retention at high temperature of metallic nanolaminates through dynamic strain ageing of one the phases.
