Experimental investigations on cryogenic friction- stir welding of similar ZE42 magnesium alloys

Abstract

In this research, the cryogenic friction stir welding (CFSW) process has been performed using a liquid nitrogen medium to join two similar ZE42 magnesium alloy plates. The new experimental setup has been designed and fabricated to supply low-temperature (−196 °C) liquid nitrogen into the welding zone. The effects of welding parameters (tool pin profile, tool rotational speed, welding speed, and axial load) on the welding characteristics (tensile strength, hardness, and wear rate) have been investigated by the Taguchi technique. The impacts of welding parameters have been analysed to predict the optimum welding characteristics. The predicted best welding settings have been utilized to compare the CFSW and normal friction stir welding (NFSW) performances. The fractography of tensile-tested specimens, hardness distributions, and microstructure of worn-out CFSW welding surfaces have been examined by scanning electron microscopy (SEM) analysis. When compared to the NFSW process, the tensile strength and hardness of CFSW are improved by 41.36 % and 35.13 %, respectively, and the wear rate has decreased by 23.53 %.