Effect of Short Fiber Reinforcement on the Fracture Toughness of Metal Matrix Composites

Evaluation of fracture toughness of short fiber reinforced metal matrix composites (MMCs) becomes important for their application as structural materials. Therefore, in this study static and dynamic fracture toughness of MMCs manufactured by squeeze casting process were investigated. A number of MMCs were tested with various matrix alloy, volume fractions and specifically types of reinforcements. It was found that static and dynamic fracture toughness of MMCs was remarkably decreased by the addition of ceramic reinforcements. Compared with static fracture toughness, the mean cause of the decrease difference of dynamic fracture toughness and notch dynamic fracture toughness is due to the effect of dynamic velocity under impact loading. The toughness of ceramic reinforced MMCs is controlled by a complex interaction between the matrix alloy and reinforcement. Important properties which influence toughness include the type of reinforcement (appearance, size), volume fraction and combination of reinforcement and the matrix alloy. Notch fracture toughness of MMCs for simple evaluation was also discussed. (C) Koninklijke Brill NV, Leiden, 2010