The local strength of microscopic alumina reinforcements

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• 作者：Goran 沤agar^a ; ^{goran.zagar@epfl.ch" class="auth_mail" title="E-mail the corresponding author} ; Vá ; clav Pejchal^a ; Martin G. Mueller^a ; Andreas Rossoll^a ; Marco Cantoni^b ; Andreas Mortensen^a
• 关键词：Micron scale ; Mechanical properties testing ; Fracture stress ; Friction ; Nanocrystalline alumina fiber
• 刊名：Acta Materialia
• 出版年：2015
• 出版时间：November 2015
• 年：2015
• 卷：100
• 期：Complete
• 页码：215-223
• 全文大小：2012 K

文摘

We measure, using an adaptation of a method designed for ceramic ball bearings, the local strength of a brittle second phase that serves to reinforce a metal. The method uses focused ion beam milling and a nanoindentation device, and is free of artifacts commonly present in micromachined specimens. It is demonstrated on Nextel 610™ nanocrystalline alumina fibers embedded in an aluminum matrix composite. Results reveal a size effect that does not follow, across size scales, usual Weibull statistics: the fiber strength distribution differs between measurements at the microscale and macroscopic tensile testing. This implies that, in micromechanical analysis of multiphase materials, highly localized events such as the propagation of internal damage require input data that must be measured at the same, local, microscale as the event; the present work opens a path to this end.