Fabrication and thermal expansion behavior of a magnesium-matrix composite with a high content of reinforcing SiC particles

Abstract

An Mg-based metal-matrix composite reinforced with 50 vol.% SiC particles was fabricated by infiltrating molten metal into porous SiC preforms, and its microstructure and thermomechanical properties were investigated. The effect of thermal processes on the thermal expansion behavior of the composite was investigated by applying 1, 10, and 20 thermal cycles within the range from room temperature to 200°C. The Kerner and Turner analytical models and a 2D unit-cell finite-element model were employed to analyze the thermal expansion behavior of the composite. The coefficient of thermal expansion (CTE) predicted by the 2D unit-cell model was in good agreement with the Kerner model, while the results from the Turner model were significantly lower. The CTE of the composite slightly increased during the thermal cycling and, after a few cycles, agreed well with the Kerner and 2D unit-cell predictions.