Machinability Studies on Hybrid Aluminum Metal Matrix Composites

Hybrid metal matrix composites are new invention in material science and Engineering. The hybrid metal matrix composites (Hybrid MMC’s) generally consist of two or more reinforcements in it. These hybrid MMC’s have several benefits over the single reinforcement. The presence of reinforcements in it exhibits improved mechanical, tribological and machinability properties. Aluminium-based MMC’s have made attention in recent years as engineering materials. But in some Aluminium-based MMC’s the use of single reinforcement may sometimes lead to weakening in its physical properties. Conversely, to overcome the problem of single reinforced composites, the idea of the use of two different types of reinforcements is being explored in the Aluminium matrix. In the hybrid MMC’s, generally one of the reinforcements will be a hard phase and the other reinforcement being a soft lubricating phase. Hard reinforcements such as TiO 2 , Al 2 O 3 , SiC, etc. will improve the hardness and abrasive wear resistance of Aluminium but it has a negative effect on the machinability of Aluminium. To balance these effects, reinforcements like graphite which is a solid lubricant can be dispersed in Aluminium along with hard reinforcements. In the present study, the paper reviews on the effect of processing techniques, effect of reinforcement and effect of machining parameters on the machinability of hybrid aluminium metal matrix composites.