Synthesis and characterisation of waste SAC- and RHA-reinforced aluminium-based composite

Two types of industrial wastes – namely, spent alumina catalyst (SAC) and rice husk ash (RHA) – were used to develop an aluminium (Al)-based metal matrix composite. The matrix material was derived from car scrap aluminium alloy wheels (SAAWs). SAC is expected to enhance the mechanical properties, and RHA proves to be very useful in increasing the strength and hardness of aluminium. Alumina particles were taken as a reference to compare waste materials as reinforcements. Microstructural studies revealed that all the reinforcement particles were bonded well with the matrix material. The mechanical properties of the matrix material improved very well when 10% alumina reinforcement particles were mixed with the SAAW matrix. However, when 3.75% SAC and 3.75% RHA were added to SAAW after ball-milling, the strength and hardness of the matrix material increased almost to that of alumina. The average particle size effect of ball-milled SAC and RHA powder was also observed to identify its effect on the mechanical properties of the developed composite.