Effect of particle size particle surface modification pressing pressure and sintering temperature on microstructure and mechanical properties P/M Al-B4C composites

In the present work, effect of particle size, particle surface modification, pressing pressure and sintering temperature on microstructure and mechanical properties were investigated at B4C reinforced aluminium matrix composites produced with powder metallurgical route. In order to improve the matrix/ reinforcement interface bonding, prior to processing, electroless nickel coating and partial oxidation were performed on the B4C particles. Three different B4C particle sizes (10, 32 and 66 mu m) were used and three different sintering temperatures (550, 590 and 630 degrees C) were performed for three different sintering time (2, 4 and 6 h) to produce the composites. Microstructures were characterised by using optical microscope and field emission gun SEM (FEG-SEM) equipped with energy dispersive analysis (EDS). Compression strength, hardness, density and porosity values were determined. After microstructural and mechanical investigations, is has seen that optimum values were obtained from fine particles modified with electroless nickel coating, sintered at 630 degrees C for 6 hours.