Characterization of the strain rate dependent behavior of nanocrystalline gold films
Characterization of the strain rate dependent behavior of nanocrystalline gold films
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纳米晶金薄膜应变率相关行为的表征
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
B. Prorok
中科院分区：
文献类型：
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作者：
L. Wang;B. Prorok
采用微拉伸技术，在应变速率为10^−4 ~ 10^−6 s^−1的情况下，对独立纳米晶金薄膜的应变速率依赖性进行了评价。薄膜厚度为0.25 ~ 1.00 μm，对应的晶粒尺寸为40 ~ 100 nm。塑性性能对应变速率、薄膜厚度和晶粒尺寸特别敏感，而弹性性能保持相对不变。较薄的薄膜表现出显著的应变速率敏感性，而较厚的薄膜仅表现出微小的变化。在较大应变速率下，观察到Hall-Petch边界硬化主导塑性流动，而随着应变速率的降低，扩散控制变形机制似乎被激活，其影响越来越大。基于位错的蠕变和与晶界扩散相关的蠕变分析表明，在低应变速率下，薄膜可能经历幂律蠕变作为主要的变形机制。
The strain rate dependence of freestanding, nanocrystalline gold films was evaluated by a microtensile technique with applied strain rates on the order of 10^−4 to 10^−6 s^−1. Film thickness ranged from 0.25 to 1.00 μm with corresponding grain sizes of 40 to 100 nm. The plastic properties were found to be particularly sensitive to strain rate, film thickness, and grain size, while the elastic property remained relatively unchanged. The thinner films exhibited significant strain rate sensitivity, while the thicker film exhibited only marginal changes. Hall–Petch boundary hardening was observed and dominated plastic flow at larger strain rates, while diffusion-controlled deformation mechanisms appeared to be activated with increasing influence as strain rate decreased. Analysis of dislocation-based and grain-boundary diffusion-related creep suggested that the films were likely experiencing power-law creep as the dominant deformation mechanism in this grain size regime at lower strain rates.