Abrasion Wear Characterization of Al-Al2O3 in-situ Particulate Composite Synthesized in Open Hearth Furnace with Manually Controlled Stirring Method

Abstract

Particulate metal matrix composites (PMMCs) have proved their viability as good alternatives to conventional alloys in high strength and stiffness applications but they are still long away from highvolume commercial production. PMMCs are a special category of virtually isotropic composites. PMMCs contain different variety of the particles either hard or soft or their mixtures in a ductile metal or alloy matrix. Therefore, PMMCs combine metallic properties (ductility and toughness) with the characteristics of reinforcement particles, often leading to greater strength, higher wear resistance and better properties at elevated temperature depending on the nature of particles. In the recent past researchers are concentrating on the easy low cost techniques for the synthesis of PMMCs, like stir casting.In the present work cast particle reinforced composites containing in-situ generated reinforcement Alumina particles have been synthesized by solidification of slurry obtain by dispersion of externally added Manganese Dioxide (MnO2) particles in the molten aluminium. Alumina particles have been generated by the reaction of the Manganese Dioxide with molten Aluminium. The chemical reaction also releases Manganese in to molten Aluminium which increases the strength of the matrix. Magnesium is added to the melt in order to help wetting of alumina particles in molten Aluminium and to retain the particles inside the melt. The present work also investigates the abrasion wear properties of the resulting cast in-situ composites. In the present work the Aluminium alloy (Al + 5% Mg) matrix composite reinforced with Alumina particles have been synthesized in the open hearth furnace with the hand stirring method. The present work shows the effect of the reinforcement on the abrasion wear properties of casted alloy and casted composites. The present work also compares the abrasion wear properties of pure Aluminium, the casted alloy and the casted composites. Aluminium based metal matrix materials have a combination of different, superior properties to an unreinforced matrix which are; increased strength, higher elastic modulus, higher service temperature, improved wear resistance, low coefficient of thermal expansion and high vacuum environmental resistance. Axen et al. [1] have noted that, in a variety of wear conditions, the particulate reinforced composites perform better than the fibrereinforced composites. Now a day’s researchers all over the world are focusing mainly on aluminium [2] because of its unique combination of good corrosion resistance, low density and excellent mechanical properties. The unique thermal properties of aluminium composites such as metallic conductivity with coefficient of expansion that can be tailored down to zero, add to their prospects in aerospace. The matrix phase for a MMC is a metal often which is ductile. MMCs are manufactured with aims to have high strength to weight ratio, high resistance to abrasion and corrosion, resistance to creep, good dimensional stability, and high temperature operability [3]. In abrasive wear there is ploughingof localized surface contacts by a softer mated material