| The mechanical propreties of a squeeze cast AC8A alloy reinforced with alumina short fibers were investigated. The Al₂O₃,AC8A composite was fabricated by the squeeze infiltration method in various casting conditions. Particular attention was given to the condition of preform temperatures. The preheating of the preforms was necessary for an easy infiltration of melt attributable to the improvement of wettability and the desorption of gas from the fiber surface. However, a too high preform temperature produced a severe interfacial reaction layer between the matrix alloy and the fiber, causing deterioration of the mechanical properties of the composite. The tensile strength of the composite decreased significantly as the preform temperature approached the melting temperature of the matrix alloy. In this work, the relationship of mechanical properties of the composite and the structure of interfacial layer has been studied using various analytical electron microscopy techniques. AES and SEM fractographic analyses were also preformed, they showed change of fracture behavior of the composite from a dominant fiber pull-out to a fiber fracture depending on preheating condition of the preform. |
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