Investigation on Mechanical and Wear Properties of ZE43 Magnesium Composites Reinforced with Silicon Nitride by Friction Stir Processing

The primary objective of this work is to fabricate ZE43 magnesium surface composites using friction stir processing (FSP) with various volume fractions of silicon nitride (Si3N4) particles (6%, 12%, and 18%). Friction stir processing were carried out on a standard vertical milling machine after the particles were initially packed, using a machined groove approach. A single-pass FSP process with a traverse feed rate of 20 mm/min and a tool rotational speed of 1200 rpm was used to produce the surface composites. The developed composites microstructure, mechanical, and wear properties were studied. Microstructure analysis showed that dynamic recrystallization occurs during FSP due to the spinning action of tool. The inclusion of reinforcement lowers the ultimate tensile strength of the ZE43 Magnesium surface composite when compared to the unprocessed composite. However, when the volume percentage of Si3N4 increases, strength increases. Furthermore, the details of the fracture surface were characterized. The addition of reinforcing particles improved the surface hardness and resistance to wear of the composites. Surface composites with 18% Si3N4 have a superior hardness of 122VHN, which in turn reduces the wear rate over other developed composites. The intricacies of the worn-out surface were further characterized.