The Influence Various Boron Carbide Reinforcement on the Microstructure and Mechanical Properties of ADC12/B4C Composite by Stir Casting

Aluminum matrix composite (AMC) was one of the promising materials for railway brake shoe, replacing gray cast iron since it has a low density and great combination between strength and wear resistance. The addition of boron carbide (B4C) which reinforced aluminum ADC12 as matrix showed better interfacial bonding than other ceramic reinforcement such as silicon carbide and alumina. However, B4C has some serious problem when used in a large amount which will decrease the wetting properties. In this study, the fabrication of AMC was carried out with the addition of 1 to 10 vf.% reinforcement through stir casting and 2 minutes argon degassing process. Magnesium as a wetting agent, Titanium-boron as a grain refiner, and strontium as a modifier were added to improve its mechanical properties. Microstructure and mechanical properties of AMC were investigated by performing Optical Microscope (OM), Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), and destructive test. The result showed that the addition of 7 vf.% B4C was the optimum variation which increased the tensile strength with the value of 231.117 MPa and hardness of 58.34 HRB also decreased impact resistance with value of 0.09375 J/mm(2) and wear rate 0.00326 x 10-(5) mm/m(3).