Transition of deformation mechanisms and its connection to grain size distribution in nanocrystalline metals
Transition of deformation mechanisms and its connection to grain size distribution in nanocrystalline metals
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DOI：
10.1016/j.actamat.2005.06.033
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发表时间：
2005-10
期刊：
影响因子：
9.4
通讯作者：
B. Zhu;R. Asaro;P. Krysl;R. Bailey
中科院分区：
文献类型：
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作者：
B. Zhu;R. Asaro;P. Krysl;R. Bailey
基于最近提出的纳米金属变形机制的Asaro，Krysl和Kad(AKK)模型和Asaro和Needleman(AN)的扩展聚集Taylor模型，发展了一个多晶本构理论。AKK模型特别关注机制，包括完全位错和部分位错的发射，以及晶界的形变孪晶和晶界滑动，以及这些机制之间的晶粒度、应变速率和随温度变化的转变。因此，特别值得关注的是颗粒尺寸分布以及平均颗粒尺寸对整个纳米晶聚集体响应的影响。颗粒尺寸分布用对数正态分布模拟，并以不同尺寸颗粒体积分数分布的形式纳入骨料模型。以电沉积镍为例，计算结果与已有的实验数据吻合较好。
A polycrystalline constitutive theory is developed based on the recently proposed model of Asaro, Krysl, and Kad (AKK) for deformation mechanisms in nanocrystalline metals and the extended aggregate Taylor model of Asaro and Needleman (AN). The AKK model is particularly concerned with mechanisms including the emission of perfect and partial dislocations, along with deformation twins from grain boundaries, and grain boundary sliding, and with the grain size, strain rate, and temperature dependent transition between these mechanisms. Thus of specific concern is the effect of grain size distribution as well as the mean grain size on overall nanocrystalline aggregate response. Grain size distributions are simulated with log-normal distributions and incorporated into the AN aggregate model in the form of distributions of the volume fraction of grains with various sizes. Numerical results for the case of electrodeposited Ni are shown to be in good agreement with available experimental data.