期刊
PHILOSOPHICAL MAGAZINE
卷 92, 期 10, 页码 1238-1260出版社
TAYLOR & FRANCIS LTD
DOI: 10.1080/14786435.2011.643250
关键词
micropillar; scaling law; dislocations; Frank-Read source; compressive testing; strength
类别
资金
- Office of Science, Office of Basic Energy Sciences, of the US Department of Energy [DE-FG02-04ER46163]
- U.S. Department of Energy (DOE) [DE-FG02-04ER46163] Funding Source: U.S. Department of Energy (DOE)
Recent micropillar compression tests of fcc and bcc single crystals have shown that 'Smaller is Stronger' even in the absence of significant strain gradients, an effect that is empirically characterised by a power-law relation. When a micropillar contains a dislocation network, this power-law relation has been explained in terms of the size-dependent operation stress of the weakest single arm dislocation sources. This single arm dislocation source model has successfully captured the power-law relation for the strength of a few fcc micropillars, but a physical interpretation has not been made by comparing different materials. We applied the model, not only to fcc but also to bcc micropillars, to understand quantitatively why different materials have different power-law exponents. Here, the different power-law exponents are interpreted by comparing material parameters that are size-independent properties. Also, by rearranging these parameters such that the formulation becomes independent of material parameters, we found an alternate form of the scaling law that is a unique function of micropillar diameter. Furthermore, recent experimental studies of the effects of increasing the dislocation density, which show hardening for large micropillars and softening for small micropillars, are interpreted in terms of the statistics of dislocation source distribution. The strengths and limitations of this statistical approach are discussed. The effects of temperature on the power-law exponents are also studied.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据