H.R Pakzaman - Department of Materials and Metallurgical Engineering, Iran University of Science and Technology (IUST
A.R Khavandi - Associate Professor
M. Divandari - Associate Professor

The current investigation involves fabrication and characterization of aluminum alloy (A356) matrix composites reinforced with the interconnected, twodimensional, steel wire performs. The composites were produced by lost foam casting process and wereheat treated to get ‘reaction interface’ (RI). Micro hardness and tensile properties of the matrix, as-cast and heat treated composites have been determined and the microstructure of the specimens was examined with optical and scanning electron microscopes. Micro structural characterization conducted on the as-cast composite samples showed some pores at the Al matrix/steel wire interface. However, nearly all the heat treated composites showed a completed bonding because of the formation of reaction layer at the interface. Hardness and strength of composites increased as compared to matrix alloy. The mechanical properties of these composites were measured and the results were correlated with the microstructure observation. While micro hardness of the composite showed variation from 150 to 56 Hv across the interface in the as-cast composite, annealed (450-525°C) composite showed a micro hardness of 810-960 Hv at the interface indicating the effectiveness of the heat treatment. The results have been discussed in terms of wetting between steel wires and the matrix, particularly the increase of hardness and tensile strength to the formation of ‘reaction interface’ due to annealing. The width of the interface increased with annealing time and temperature.

Aluminum matrix composites, Reaction interface, Annealing, Mechanical properties, Lost foam casting