PHYSICO-MECHANICAL PROPERTIES AND MICROSTRUCTURE RESPONSES OF HYBRID REINFORCED Al6063 COMPOSITES TO PKSA/SiC INCLUSION

Abstract

The study examined the microstructure and mechanical properties of Al-Mg-Si alloy reinforced with palm kernel shell ash (PKSA) and silicon carbide (SiC). The alloy matrix was reinforced with SiC (2-8 wt.%) and PKSA (2 wt.%). The double stir-casting method was used to prepare the hybrid composite. The density, porosity, hardness, tensile, and fracture toughness properties of the produced samples were evaluated based on ASTM standards. Identification of phases present in the composite was done using a PANalytical Empyrean diffractometer, while the microstructural characterization was examined using a scanning electron machine with electron dispersive spectrometer attachment. The density values increase as the SiC contents in the composites increase, while the porosity percentage of all the composites were below 4%. As the reinforcement particulates increase, the mechanical properties of the reinforced composite improved with hardness value (73 – 85.5 BHN); yield strength (81 – 102 MPa); and ultimate tensile strength (123 – 133 MPa) compared with the matrix alloy of 73 BHN, 79 MPa, and 116 MPa, respectively. However, the percentage elongation and the fracture toughness of the reinforced samples reduced to 34.2 and 40.11%, respectively. The phases identified in the composites were Al, SiO2, Fe3Si, MgO, and SiC, which are hard but brittle strengtheners to improve the mechanical properties of the composites. The microstructure of the reinforced samples showed uniformly dispersed reinforcement in the matrix through grain refinement as assisted by the stir casting method utilized. SiC was a better strengthener as the quantity increased in the matrix compared to PKSA in the reinforced sample. The synthesized hybrid composites would be applicable as building materials such as aluminium frames and roofing sheets.