Mechanical Characterization of Magnesium Alloy AZ31B Processed by Friction Stir Welding and Gas Tungsten Arc Welding

Abstract

Magnesium alloy AZ31B plates are welded utilizing two different welding techniques. One is friction stir welding, a strong solid state procedure, and other tungsten inert gas welding, a famous fusion welding technique. Imperfection free, complete infiltration welds are acquired after several attempts utilizing different procedure parameters such as tool rotational speed, tool transverse speed, peak current, gas flow rate etc. Then impact of two welding methods are compared on mechanical properties of AZ31B joints that were assessed utilizing  tensile test, fatigue test, Microhardness measurement, metallography, stereography and fractography. Welds obtained from friction stir welding technique showed better tensile and fatigue properties as compared with tungsten inert gas process. Increment in the hardness is observed in the gas tungsten arc welded joint, and decrease in friction stir joints. Welds by friction stir technique demonstrated fine grains in the heat affected zone (HAZ), and also in the stir zone (SZ). It is revealed that both procedures are appropriate to get the good joints of the magnesium alloy AZ31B, but welds by friction stir process showed the stronger welds.