Discussion of the dependence of the effect of size on the yield stress in hard materials studied by microcompression of MgO

作者：Korte S^*; Clegg W J

来源：Philosophical Magazine, 2011, 91(7-9): 1150-1162.

DOI：10.1080/14786435.2010.505179

• microcompression
• brittle materials
• size effect

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.

• 出版日期2011