Effects of dwell time on the microstructures and mechanical properties of water bath friction stir spot-welded AZ31 magnesium alloy joints. Issue 1 (January 2016)

• Record Type: Journal Article
• Authors: Xie, Xiong; Shen, Jun; Gong, Fubao; Wu, Dong; Zhang, Tao; Luo, Xiong; Li, Yang
• Is Part Of: International journal of advanced manufacturing technology. Volume 82:Issue 1/4(2016)
• Page Start: 75
• Page End: 83
• Publication Date: 2016-01
• Subjects: AZ31 magnesium alloy -- Water bath friction stir spot welding -- Dwell time -- Microstructures -- Mechanical properties; Manufacturing processes -- Periodicals; Production engineering -- Periodicals; 670.427
• DOI: 10.1007/s00170-015-7361-2
• Languages: English
• ISSNs: 0268-3768

Abstract

Abstract In this work, a new water bath friction stir spot welding (WB-FSSW) process was developed. The effects of dwell time on the microstructures and mechanical properties of the WB-FSSW-welded AZ31 magnesium alloy joints were investigated by microstructural observation, tensile tests, and microhardness tests. It was found that compared with those of ordinary FSSW welds, the WB-FSSW welds have poorer tensile shear force, almost equal tensile shear strength per unit areaτ and higher microhardness mainly due to the narrower bonded zone width of the hooks and microstructures in the welded joints, respectively. Moreover, with the increase in the dwell time, the microhardness and the tensile shear strengthen per unit areaτ of the WB-FSSW-welded joints increased firstly and then decreased because of the fluctuant evolution of grain size ofα -Mg and the volume fraction of theβ -Mg17 All2 . The optimal dwell time for the WB-FSSW welding was from 10 to 15 s whereby the finest grains and the highest mechanical properties of the welded joints can be achieved.