Dislocation-based modeling of the mechanical behavior of epitaxial metallic multilayer thin films
Dislocation-based modeling of the mechanical behavior of epitaxial metallic multilayer thin films
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DOI：
10.1016/j.actamat.2004.11.009
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发表时间：
2005-02
期刊：
影响因子：
9.4
通讯作者：
Qizhen Li;P. Anderson
中科院分区：
文献类型：
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作者：
Qizhen Li;P. Anderson
采用三维位错元胞自动机模型模拟了纳米结构金属多层膜在面内双向拉伸载荷作用下的屈服和硬化过程。该薄膜由两种类型的交替，单晶FCC层（001）外延，在无应力晶格参数失配，但没有弹性模量失配。模拟监控操作的界面和线程源的长度大于单个层的厚度。在较大的层厚度，强度随着层厚度的减小而增加，这是由于滑移限制到各个层。在足够小的层厚度，滑移约束是不可能的，即使在初始阶段的塑性变形。因此，强度不受层厚度控制，而是受源极长度以及相干应力和界面势垒强度控制。这里，强度可以增加、减少或达到平台，这取决于源极长度和势垒强度如何随层厚度变化。
A 3D dislocation cellular automaton model is employed to simulate yield and hardening in nanostructured metallic multilayer thin films during in-plane, biaxial tensile loading. The films consist of two types of alternating, single-crystalline FCC layers with (001) epitaxy, a mismatch in stress-free lattice parameter, but no elastic modulus mismatch. The simulations monitor the operation of interfacial and threading sources with lengths greater than the individual layer thickness. At larger layer thickness, strength increases with decreasing layer thickness, due to slip confinement to individual layers. At sufficiently small layer thickness, slip confinement is not possible, even during initial stages of plastic deformation. Consequently, strength is not controlled by layer thickness but rather by source length, as well as coherency stress and interfacial barrier strength. Here, strength may increase, decrease, or reach a plateau depending on how source length and barrier strength vary with layer thickness.