Intrinsic-extrinsic size effect relationship for micromechanical tests
Intrinsic-extrinsic size effect relationship for micromechanical tests
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DOI：
10.1016/j.scriptamat.2018.10.045
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发表时间：
2019-03
影响因子：
6
通讯作者：
J. Wharry;K. Yano;Priyam V. Patki
中科院分区：
文献类型：
--
作者：
J. Wharry;K. Yano;Priyam V. Patki
微型机械测试通常用于评估材料的性能，包括薄膜、纳米结构和辐照材料。然而，当微型化的试样几何形状包含太少的位错源时，就会产生试样尺寸效应，从而导致屈服应力升高。尺寸效应受外在（试样尺寸）和内在（微观结构）因素的控制。在这里，我们总结了档案文献中报道的微压缩柱、微悬臂弯曲和弯曲研究的外在和内在尺寸效应。我们发现了内在和外在尺寸效应之间的近似线性关系。当外在尺寸大于内在尺寸时，可以测量有意义的机械性能。
Miniaturized mechanical tests are commonly utilized to evaluate properties of materials, including thin films, nanostructured, and irradiated materials. However, the specimen size effect occurs when miniaturized sample geometries contain too few dislocation sources, resulting in elevated yield stresses. The size effect is controlled by extrinsic (specimen dimensions) and intrinsic (microstructure) factors. Here, we summarize extrinsic and intrinsic size effects from micro-compression pillar, micro-cantilever bend, and flexure studies reported in the archival literature. We find an approximately linear relationship between intrinsic and extrinsic size effects. Meaningful mechanical properties can be measured when extrinsic size dominates the intrinsic size.