Microstructure, hardness, and wear resistance of AZ91 magnesium alloy produced by friction stir processing with air-cooling

Abstract Friction stir processing (FSP) was used to modify the surface layer of AZ91 magnesium alloy. The treatment carried out using a jet cooling nozzle, generating stream cold air and enabling intensive friction processed (FSPed) zone. Single-pass FSP tool rotational speed 500 rpm travel 30 mm/min. conducted truncated cone-shaped with threaded side surface. Strong grain refinement microstructural changes typical for were found in all samples. Very fine, equiaxed recrystallized grains dominated stirring In samples modified greater obtained than case naturally cooled material. average size part zone 1.4 μm 9 air-cooling natural cooling, respectively. Both specimen air-cooled characterized by distinctly higher hardness base Vickers 91 HV0.1 FSPed sample system 85.5 as-cast alloy 64 HV0.1. Slightly wear resistance nozzle relation sample. Based on research, high efficiency during found.