Low cycle fatigue behavior of AZ31 magnesium alloy joined by friction stir welding

Abstract

This study, aims to weld the 5.2 mm thick AZ31 magnesium alloy with conventional friction stir welding at the highest joining efficiency. As a result of the experiments, 88% joining efficiency in tensile strength has been obtained at 1250 rpm, 400 mm.min-1 welding parameter. As a result of micro-macrostructure photographic examinations of the samples joined with these parameters, it is seen that the joining is fully realized. Samples joined with these parameters have been used in fatigue tests. According to the strain-controlled low cycle fatigue test results performed on welded and base metal samples, the base metal samples have exceeded the 50,000-cycle limit without failure, with an elongation rate of 0.3%, and the welded samples with an elongation rate of 0.2%. Low cycle fatigue parameters of welded and base metal samples have been obtained according to the Coffin-Manson-Basquin equation. In joining AZ31 alloy with FSW, a high joining efficiency of 88% was achieved. Similar fatigue test results showed that the weld quality was retained along the joint. Coffin-Manson-Basquin equation constants were determined.