DEVELOPMENT AND WEAR CHARACTERIZATION OF AL7075/AL2O3/SIC HYBRID PARTICULATE METAL MATRIX COMPOSITE DEVELOPED BY STIR CASTING

Abstract

In this work Hybrid Metal Matrix Composite have been developed using stir casting process for improving the Wear Behavior at lower cost. The silicon carbide (SiC) as one of the reinforcement used with 3% weight fraction and Alumina (Al2O3) as the major reinforcement in 3%, 6%, 9% &12% weight fraction. Al-7075 has been considered as the matrix material .The low cost stir casting process has been used for the development of the composite system. The matrix material was melted in electric furnace and the heat treated reinforcement in the desired weight fraction have been added followed by constant stirring the melt. The temperature of the melt held at 750oC. The pouring temperature was recorded which has relation to quality of the casting. The casted specimen have been obtained in the form of cylindrical rod of 20mm diameter and 200mm length for carrying out tribological tests. Microstructure analysis reveals the uniform distribution of reinforcements in the aluminum matrix. The density of the composite increases with the increase in weight fraction. The composite density found to lie in between the density range of matrix and the reinforcement. The pin on disc wear test carried on all the samples at various speeds of 300,600,900 and 1200 rpm, varying load of 1kg,2kg,3kg&4kg and varying sliding distances of 1km,2km,3km&4km. These test reveals that the wear resistance increases with the increase in the reinforcement weight fraction. The increase in the speed reduces the wear rate and wear rate increases in with increase in sliding distance. The wear rate and coefficient of the composite reduces for higher volume fraction. The addition of SiC apart from improving the wear rate reduces the noise and vibration at higher speed and load condition. The overall tribological property improves due to addition of the two reinforcement.