Grain size effects in aluminum processed by severe plastic deformation
Grain size effects in aluminum processed by severe plastic deformation
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DOI：
10.1016/j.msea.2017.10.077
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发表时间：
2018-01
期刊：
影响因子：
6.4
通讯作者：
T. Koizumi;M. Kuroda
中科院分区：
文献类型：
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作者：
T. Koizumi;M. Kuroda
我们使用一组通过等通道角挤压 (ECAP) 连续细化晶粒的样品和另一组通过 8 道 ECAP 加工并随后逐步退火以产生较粗晶粒的样品，研究了晶粒尺寸对铝屈服强度的影响。对所有样品进行拉伸测试。针对不同的强化贡献采用线性加法模型，将观察到的屈服强度分解为位错相关和晶粒尺寸相关的强化贡献。前者使用泰勒方程直接评估，位错密度由威廉姆森-霍尔方法确定，后者通过从观察到的屈服强度中减去前者和摩擦应力来量化。结果发现，对于 ECAP 处理的样品，与晶粒尺寸相关的强化量与传统 Hall-Petch 关系的外推一致，并且在退火后出现明显与晶粒细化相关的额外强化。
We investigated the effects of the grain size on the yield strength of aluminum using a group of samples with grains successively refined by equal-channel angular pressing (ECAP) and another group of samples produced by 8 ECAP passes and subsequently annealed step by step to produce coarser grains. Tensile tests were performed on all the samples. Adopting a linear addition model for different strengthening contributions, the observed yield strength was resolved into dislocation-related and grain size-related strengthening contributions. The former was directly evaluated using the Taylor equation with dislocation densities determined by the Williamson–Hall method, and the latter was quantified by subtracting the former and the friction stress from the observed yield strength. It was found that for the as-ECAP-processed samples, the amount of the grain size-related strengthening was consistent with an extrapolation of the conventional Hall–Petch relation, and marked extra strengthening, which was clearly related to the grain refinement, appeared after annealing.