Coupled DDD–FEM modeling on the mechanical behavior of microlayered metallic multilayer film at elevated temperature
Coupled DDD–FEM modeling on the mechanical behavior of microlayered metallic multilayer film at elevated temperature
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DOI：
10.1016/j.jmps.2015.09.007
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发表时间：
2015-12
影响因子：
5.3
通讯作者：
Minsheng Huang;Zhenhua Li
中科院分区：
文献类型：
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作者：
Minsheng Huang;Zhenhua Li
为了研究微层金属薄膜（MMMF）在高温下的机械行为，本研究开发了一种增强型离散连续模型（DCM），该模型将二维爬升/滑翔离散位错动力学（2D-DDD）与线弹性有限元法（FEM）耦合而不是叠加。在本耦合方案中，进行了两个特殊处理。一是解决 DDD 模块捕获的塑性应变如何作为特征应变正确传递到 FEM 模块；另一个是回答FEM模块计算得到的应力场如何准确地传递到DDD模块以驱动那些离散位错正确移动。通过这两种特殊处理，仔细考虑了相邻位错之间以及位错堆积和相间边界（IB）之间的相互作用，这对于MMMF的强化效果至关重要。通过将计算预测结果与均质材料和双材料界面附近位错的理论解进行比较进行验证后，该 2D-DDD/FEM 耦合方案用于模拟 MMMF 在高温下的拉伸力学行为。详细研究了MMMF的强化机制和层厚效应，特别关注位错爬对其的影响。
To investigate the mechanical behavior of the microlayered metallic thin films (MMMFs) at elevated temperature, an enhanced discrete-continuous model (DCM), which couples rather than superposes the two-dimensional climb/glide-enabled discrete dislocation dynamics (2D-DDD) with the linearly elastic finite element method (FEM), is developed in this study. In the present coupling scheme, two especial treatments are made. One is to solve how the plastic strain captured by the DDD module is transferred properly to the FEM module as an eigen-strain; the other is to answer how the stress field computationally obtained by the FEM module is transferred accurately to the DDD module to drive those discrete dislocations moving correctly. With these two especial treatments, the interactions between adjacent dislocations and between dislocation pile-ups and inter-phase boundaries (IBs), which are crucial to the strengthening effect in MMMFs, are carefully taken into account. After verified by comparing the computationally predicted results with the theoretical solutions for a dislocation residing in a homogeneous material and nearby a bi-material interface, this 2D-DDD/FEM coupling scheme is used to model the tensile mechanical behaviors of MMMFs at elevated temperature. The strengthening mechanism of MMMFs and the layer thickness effect are studied in detail, with special attentions to the influence of dislocation climb on them.