Effect of boron carbide and Kaoline reinforcements on the microstructural and mechanical characteristics of aluminium hybrid metal matrix composite fabricated through powder metallurgy technique

In the present work Al- 10% B4C- X% Kaoline (X = 0, 2, 4, 6, 8) hybrid metal matrix composite (HMMC) was fabricated through powder metallurgy technique. Physical and mechanical properties like density, Hardness, Porosity, Ultimate tensile strength (U.T.S) and Impact energy were studied for the fabricated composite samples. Results concluded that there was a 91.93% increment in hardness and 75% increment in U.T.S of the fabricated samples was observed for Al-10%B4C-4%Kaoline HMMC. However, incorporation of kaoline reinforcement beyond 4% leads to the formation of agglomerates in the composites reducing the U.T.S from 238 MPa to 186 MPa and hardness from 119 VHN to 101 VHN. The fabricated composite specimens were characterised using an X-ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The XRD patterns reveal the presence of Aluminium, B4C and kaoline particles. In addition to this, the presence of intermetallic phases was observed for Al-10%B4C-6% Kaoline and Al-10%B4C-8% kaoline HMMC. Uniform distribution of reinforcements and formation of agglomerations for 6% and 8% kaoline reinforcements was confirmed by SEM and their respective EDS mapping. Results showed that the Al-10 % B4C- 4% Kaoline has superior mechanical properties compared to monolithic aluminium