Development of Cast Magnesium Matrix Composites

Near net-shape casting of magnesium matrix composites provides an interesting opportunity to expand the applications of cast magnesium products. In this work, squeeze casting was used to evaluate a series of different short fiber preforms infiltrated with a matrix of high purity AZ91 alloy. Reactions between the fibers and 1) the binder in the preform, and 2) the liquid alloy were examined by metallography and related to the infiltration sequence. Short fibers of Al₂O₃ (Saffil RF grade) were found to be the most promising reinforcement, based upon the structure and tensile properties of Saffil-reinforced AZ91 alloy at both room and elevated temperature.