Aluminium based metal matrix hybrid composites for electronics applications

Abstract

The conventional enormous materials have the limitation in good combination of density stiffness, toughness and strength etc. The composites for assuring the materials to overcome this imperfection and to meet the forever demand in modern days technologies. Compared to reinforced alloys the metal matrix (MMCs) considerably improved properties like good wear resistance, specific modulus and strength. The composites containing moderate reinforcement and low density in the increasing interest in composites. There are different intermittent dispersions used in the fly ash which is one of the most inexpensive and low density reinforcement available in large quantity and the solid waste by-products is obtained during combustion of coal in thermal power plants. In automotive and small engine applications, the composites with fly ash reinforcement are possible to overcome the cost barrier in extensive application. The incorporation of fly ash particles in aluminium alloys will improve another use of low cost waste by product and also which serves as potential for conserving energy. The intensive aluminium reduces the cost of aluminium products. To overcome the use of metal matrix composite the limitation of polymer matrix composites are at high temperature. The composites are prepared by powder metallurgy techniques, by infiltration molten metal. In another ways the fabrication which includes plasma spraying, vapour and electro deposition are proceeded from diffusion bonding. The metal matrix composites are finding applications in defence, automotive, aerospace etc. Addition to metal matrix composites, intermetalics such as titanium, nickel, niobium alumnidesetc are used at high temperaturesFrom the light of the literature AA6061 and AA7075 are appropriate base alloy with reinforcement for graphite and SiC particles for various tribological application under dry sliding conditions. The tribological and mechanical properties of hybrid composites to suit for various engineering applications. By a liquid metallurgy route, the aluminium metal matrix composites are manufactured with graphite reinforcement of 5%wt and 5, 10, 15 and 20% wt. SiC particles reinforced with an average particulate size of about 16and#956;m were prepared. In a graphite crucible, about 1kg of AA 6061 was melted when heats up to 850ºC. The preheated stirrer was introduced in the melt, when the temperature of the melt was about 30ºC above the pouring temperature (850ºC) and this is carried-up to a proper mixing of slurry. Later, it is stirred at 500rpm, by use of an impeller attached with variable speed motor. This stirring is carried up to a uniform distribution of all particles. Stirring of melt was started and preheated SiC particulates were introduced in the % wt. of 5, 10,15 and 20 followed by the addition of 5 % wt. of graphite. The stirring was carried up to ensure a proper mixing of slurry. Then it is poured into the preheated steel moulded and then the casted composite undergoes the T6 heat treatment which is followed by artificial ageing. Hence the ten newline