Discrete dislocation analyses of circular nanoindentation and its size dependence in polycrystals
Discrete dislocation analyses of circular nanoindentation and its size dependence in polycrystals
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多晶中圆形纳米压痕的离散位错分析及其尺寸依赖性
DOI：
10.1016/j.actamat.2008.02.012
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发表时间：
2008-07
期刊：
影响因子：
9.4
通讯作者：
Hou, Chuantao
中科院分区：
文献类型：
--
作者：
Ouyang, Chaojun;Li, Zhenhuan;Huang, Minsheng;Hou, Chuantao
纳米压痕已被广泛用于测量材料在微米和纳米尺度的力学行为。然而，纳米/微压痕的材料响应及其内在机制是非常复杂的，特别是在考虑多晶材料的情况下。基于Van der Giessen和Needleman的二维离散位错塑性[Van der Giessen E，Needleman A.Model Simul Mater Sci Eng 1995；3：689]，通过数值模拟研究了用圆形压头在多晶体中进行的纳米压痕。研究了压痕硬度与压头半径、晶粒度、压痕深度和晶界到压头距离四个典型特征尺寸之间的关系。结果表明，这些特征尺寸对纳米压痕硬度有较大影响。进一步研究表明，它们的影响主要通过两种途径起作用，即通过应变硬化和压痕尺寸效应。尽管这两种效应都依赖于大小，但它们的潜在机制显然不同。在这种情况下，应变硬化效应主要与晶界的约束和位错对位错滑移的阻碍有关，而压痕尺寸效应则与圆形压头下的平均应变梯度有关。
Nanoindentation has been extensively used to measure the mechanical behavior of materials at the micro- and nanoscale. However, the material response of nano/microindentation and its intrinsic mechanisms are very complicated, especially when considering heterogeneous polycrystalline materials. In this contribution, nanoindentation in polycrystals, performed with a circular indenter, is studied by numerical modeling based on the two-dimensional discrete dislocation plasticity of Van der Giessen and Needleman [Van der Giessen E, Needleman A. Model Simul Mater Sci Eng 1995;3:689]. The dependence of indentation hardness is investigated with respect to four typical characteristic dimensions: indenter radius, grain size, indentation depth, and the distance between the grain boundary and the indenter. Results show that these characteristic dimensions have considerable influence on the nanoindentation hardness. Further investigation shows that their influence takes effect mainly in two ways, i.e. via strain hardening and the indentation size effect. Although both effects are size dependent, their underlying mechanisms are clearly different. For the present polycrystal case, the strain hardening effect is mainly associated with the constraints of grain boundaries and dislocation obstacles to the dislocation glide, while the indentation size effect is related to the average strain gradient beneath the circular indenter.
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影响因子：
4.1
作者：
H. Kreuzer;R. Pippan
通讯作者：
H. Kreuzer;R. Pippan
影响因子：
3.9
作者：
R. Al-Rub
通讯作者：
R. Al-Rub
影响因子：
9.8
作者：
H.H.M. Cleveringa;V. Giessen;A. Needleman
通讯作者：
H.H.M. Cleveringa;V. Giessen;A. Needleman
影响因子：
6
作者：
Juyoung Kim;B. Lee;D. Read;D. Kwon
通讯作者：
Juyoung Kim;B. Lee;D. Read;D. Kwon
DOI：
10.1007/978-3-662-53605-6_110-1
发表时间：
2020
期刊：
Encyclopedia of Continuum Mechanics
影响因子：
--
作者：
L. Bardella
通讯作者：
L. Bardella