Discussion of the dependence of the effect of size on the yield stress in hard materials studied by microcompression of MgO
Discussion of the dependence of the effect of size on the yield stress in hard materials studied by microcompression of MgO
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DOI：
10.1080/14786435.2010.505179
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发表时间：
2011-01-01
影响因子：
1.6
通讯作者：
Clegg, W. J.
中科院分区：
文献类型：
--
作者：
Korte, S.;Clegg, W. J.
微压缩在尺寸效应的研究中引起了相当大的兴趣，主要是在软金属中。在具有较高体流变应力的材料上进行实验的文献中几乎没有可用的数据，尽管已经表明由于试件尺寸较小，该技术可以成功地用于抑制裂纹。在这里，对氧化镁进行了微压缩，以证明单独激活不同滑移系统的可能性。结合透射电子显微镜获得的屈服应力表明，氧化镁中的硬滑移和软滑移系统都可以单独表征。因此，微压缩是一种潜在的替代在围压或高温下对脆性材料进行宏观测试的方法。为了确定尺寸对这种测量的影响，比较了氧化镁中两种滑移系的测量结果和文献中的结果。结果表明，材料的体积屈服应力可以用来在微观尺度上估计尺寸对其屈服应力的影响。
Microcompression has attracted considerable interest in the study of size effects, mainly in soft metals. Little data is available in the literature on experiments on materials with a higher bulk flow stress, although it has been shown that the technique can be successfully employed to suppress cracking due to the small specimen dimensions. Here, microcompressions on MgO were carried out to demonstrate the possibility of individually activating different slip systems. The yield stresses obtained in conjunction with transmission electron microscopy show that both the hard and soft slip system in MgO can be characterised individually. Microcompression is, therefore, a potential alternative to macroscopic testing of brittle materials under confining pressure or at high temperatures. To determine the influence of size on such measurements, results on the two slip systems in MgO and from the literature are compared. It is found that the bulk yield stress of a material might be used to estimate the effect of size on its yield stress at the microscale.