Modeling of the size effects on the behavior of metals in microscale deformation processes
Modeling of the size effects on the behavior of metals in microscale deformation processes
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DOI：
10.1115/1.2714582
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发表时间：
2007-06-01
影响因子：
4
通讯作者：
Koc, Muammer
中科院分区：
文献类型：
--
作者：
Kim, Gap-Yong;Ni, Jun;Koc, Muammer
为了精确地分析和设计微成形工艺，在微/细观尺度上考虑尺寸效应，正确地建模材料行为是必要的。已知金属材料中存在两种尺寸效应。一个是“晶粒尺寸”效应，另一个是“特征试样尺寸”效应.本研究探讨了特征/试样尺寸效应，并引入了一个缩放模型，结合特征/试样和晶粒尺寸效应。预测的尺寸效应进行了比较，从以前的研究中获得的三个独立的实验：一个简单的压缩与一个圆形的标本，一个简单的拉伸与一个圆形的标本，和一个简单的拉伸金属板。预测结果与实验结果吻合得很好。通过引入两个参数α和δ来实现小型化效应的量化，这两个参数可以由缩放参数n确定到Hall-Petch方程。尺度模型提供了一种简单的方法来模拟尺寸效应的长度尺度的一对夫妇的颗粒，并扩展使用连续塑性理论的微/中尺度。
For the accurate analysis and design of microforming process, proper modeling of material behavior at the micro/mesoscale is necessary by considering the size effects. Two size effects are known to exist in metallic materials. One is the '' grain size '' effect, and the other is the '' featurelspecimen size '' effect. This study investigated the feature/ specimen size effect and introduced a scaling model which combined both feature/ specimen and grain size effects. Predicted size effects were compared with three separate experiments obtained from previous research: a simple compression with a round specimen, a simple tension with a round specimen, and a simple tension in sheet metal. The predicted results had a very good agreement with the experiments. Quantification of the miniaturization effect has been achieved by introducing two parameters, a and 6, which can be determined by the scaling parameter n, to the Hall-Petch equation. The scaling model offers a simple way to model the size effect down to length scales of a couple of grains and to extend the use of continuum plasticity theories to micro/mesolength scales.