Comparing the effect of processing temperature on microstructure and mechanical behavior of (ZrSiO4 or TiB2)/aluminum composites

Recently, a large number of metal matrix composites have been developed for high-performance applications. The first requirement for superior performance of a composite material is the homogeneous distribution of the reinforcing phase. In particulate-reinforced composites, any agglomeration of reinforcement particles deteriorates the mechanical properties of composite. Stir casting route has been used to achieve homogeneity of particle distribution throughout the matrix. In present study, ZrSiO4 and TiB2 particles were incorporated in A356.1 alloy. The size of ZrSiO4 and TiB2 particles was 1 mu m. Reinforcement particles were added to melted aluminum at different temperatures above pure aluminum melting point (750, 850, 950 degrees C). The volume fraction of reinforcement particles was 5%. After addition of reinforcement, stirring was continued for 12 min for better distribution and better solidification conditions. The microstructure and mechanical behavior of prepared composites were studied. Scanning electron microscopy and X-ray diffraction were used to investigate dispersion of reinforcement particles in aluminum matrix and chemical composition of composites. Hardness and tensile tests were carried out to test mechanical properties. The results of these experiments show that the mechanical properties and microstructure of composites were changed by increasing temperature; also the best condition of ZrSiO4 case was 750 degrees C but 850 degrees C for TiB2. (C) 2008 Elsevier B.V. All rights reserved.