Mould Temperatureand Mechanical Properties of Cast Aluminum-Silicon Carbide Composite

Abstract

Abstract Effect of mould preheating on the mechanical properties of stir cast Al-SiC has been studied. The silicon carbide particles (83��) are washed with distilled water, oven dried at 100 ℃ for 2hours prior to use. The mould temperature is varied from 200-600℃before the molten mixture is poured into it. Cast samples are divided into three groups, heated to 400 o C normalized, annealed and quenched. These heat treated samples are then subjected to mechanical and structural analyzes. Results show that tensile strength and hardness dec line with rise in mould temperature while elongation and impact strength increase. The highest tensile strength ( ~57MPa) is recorded for quenched samples at mould temperature of 200 0 C and the lowest (~35 MPa) in annealed samples at the same mould temperature.The hardness increase considerably withquenched>normalised>annealed. Keywords Mould Temperat ure, Aluminium-Silicon Carbide, Mechanical Properties, Heat Treatment 1. Introduction With the development of industry and technology, the use of aluminum and its alloys due to its many technical propertiesadvantages, is on the increase worldwide [1]. The increase importance of aluminum and its alloys in recent years, have resulted in its high rate of consumption compare to iron -steel products as its now more in use in such areas as electrical, chemical, medicine, construction, automoti ve and aviation and their sub -industries [2- 4] . Particulate-reinforced aluminum alloys are moreattractive than conventional aluminum alloys for applicationsrequiring higher stiffness and strength. Reinforcementby particles or short fibers of SiC has proved to be advantageous since it offers composite materials with isotropic properties at low cost. Al-SiC composit e is a material that has s ilicon carbide particles (SiCp)as filler inaluminum alloy matrix [5] resulting ni lightweight, high thermal conductivity and controlled thermal expansion material. Al-SiCapplications include base plates for Insulated Gate Bipolar Transistors (IGBTs) for traction applications, large industrial equipment, electric vehicles, industrial robotics, welding machines and power supplies for medical imaging systems, as well as in Printed Wiring board (PWB) cores for defence electronics applications[6]. The introduction of SiCp in aluminium matrix has been shown to give good wear resistance and