Load partitioning during creep of powder metallurgy metal matrix composites and Shear-Lag model predictions

Abstract

Itwas shownin apreviouswork that the load transfermechanism plays a relevant role during the high temperature deformation of discontinuously reinforced metal matrix composites, MMCs. This idea emerged from the comparison of the creep data of a powder metallurgy, PM, 6061Al–15vol%SiCw composite and the corresponding un-reinforced 6061Al alloy. The idea was further supported by a qualitative analysis of the creep data of MMCs from a number of investigations reported in the literature, particularly of PM composites. In the present work a quantitative and more thorough study of the creep data of these PM composites is presented. Specifically, a well-known Shear-Lag model is used to compare the composites creep strength increment and the predicted load transferred to the reinforcement. These new results sustain more thoroughly the relevance of the load transfer mechanism during creep of MMCs.