Strength of metallic multilayers at all length scales from analytic theory of discrete dislocation pileups
Strength of metallic multilayers at all length scales from analytic theory of discrete dislocation pileups
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DOI：
10.1080/14786430500156799
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发表时间：
2005-10
影响因子：
1.6
通讯作者：
L. Fang *;L. Friedman
中科院分区：
文献类型：
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作者：
L. Fang *;L. Friedman
金属多层膜可用作超高强度涂层。它们表现出非常强的霍尔-佩奇式尺寸效应，其中机械强度取决于层厚度。这一趋势表明位错堆积理论可用于根据基本和微观材料参数预测多层膜的强度。在大长度尺度上，多层膜的行为可以通过比例定律来描述。在小长度尺度上，离散位错的影响变得很重要，并且会出现与比例定律的较大偏差。完整的分析模型应适用于所有长度尺度，并正确考虑这种位错离散效应。这里提出了这样的模型。多层膜的层厚被分为四个长度尺度范围，并且给出了每个范围内的长度尺度和多层强度的简单解析公式。该模型应用于 Cu/Ni 多层膜，并将预测强度与实验数据进行比较。此外，还给出了预测的多晶多层变形图。
Metallic multilayers can be used as ultra-high strength coatings. They exhibit a very strong Hall–Petch-like size-effect where the mechanical strength depends on the layer thickness. This trend suggests that dislocation pileup theory can be used to predict the strength of multilayers from fundamental and microscopic material parameters. At large length scales, the behavior of multilayers can be described by a scaling law. At small length scales, the effect of discrete dislocations becomes important, and large deviation from the scaling law occurs. A complete analytic model should apply at all length scales and properly account for this dislocation discreteness effect. Such a model is proposed here. The layer thickness of multilayers are divided into four length-scale regimes, and simple analytic formulas are given for both the regime length scales and multilayer strength in each regime. The model is applied to Cu/Ni multilayers and the predicted strength is compared to experimental data. Furthermore, the predicted polycrystalline multilayer deformation map is presented.