Hybrid metal matrix composites (MMCs) in which adjoining matrices have different plastic responses have potential to offer more attractive damage tolerance properties than conventional MMCs [1]. At the interface of two dissimilar metal matrices, both capable of deforming plastically, the accentuated free-edge stresses may cause intermatrix decohesion to form an interface crack. In this article, the solution of a local-global analysis to determine the mechanics environment governing onset of such intermatrix debonding is presented. First an effective method of asymptotic local analysis for the singular interfacial stress in plastically deforming hybrid MMCs [1-5] is summarized and new results are presented. Then, the generalized stress intensity factor that scales the free-edge interfacial stresses is solved by a global analysis for several illustrative cases. The global analysis is performed via elastic-plastic finite-element method. The solutions presented completely characterize the dominant mechanical environment that governs the onset of intermatrix decohesion. The solutions, with proper interpretation, are also applicable to hybrid MMCs at elevated temperatures with matrices deforming by power-law creep. [6]
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