Fabrication of Magnesium Alloy Based Composites Reinforced by Uniaxially Oriented SiC Continuous Fibers Using Low Pressure Infiltration Method

摘要

Mg-alloy-based composites, a type of metal matrix composites (MMC), wherein SiC continuous fibers are uniaxially oriented are fabricated using a low-pressure infiltration method. Al particles are dispersed between the SiC fibers in the preform to orient the SiC fibers with equal spacing. The optimum particle size and additive amount of Al particles are determined by evaluating the uniformity of the SiC fiber spacing and the bending strength. In addition, the optimum infiltration pressure is determined by evaluating the ratio of the infiltration failure (the part where the molten alloy does not completely fill the space between the SiC fibers) and the bending strength. The results show that there is a threshold value for the infiltration pressure (0.30 MPa at a SiC fiber volume fraction of 20). When the infiltration pressure exceeds the threshold value, the ratio of the infiltration failure increases and the bending strength decreases because the areas with slightly wide fiber spacing are preferentially infiltrated, and the areas with narrow fiber spacing are not infiltrated. The maximum strength of the Mg-alloy-based MMC obtained herein was 415 MPa at a SiC fiber volume fraction of 20.