Large load friction stir welding of Mg–6Al–0.4Mn–2Ca magnesium alloy

ABSTRACT

Friction stir welded (FSW) magnesium alloys usually exhibit a lower yield strength and elongation compared with base materials. In this study, large load FSW associated with an extremely low welding speed and rotation rate were applied to a non-combustive Mg–6Al–0.4Mn–2Ca magnesium alloy to modify the microstructure and texture in the weld zone and improve the mechanical properties of the joint. The twin structure in the stir zone provided adequate barriers for dislocation motion for strengthening and created more local sites for nucleating and accommodating dislocations, thereby elevating ductility and strain hardening in the transverse tensile test. The results showed that the yield strength and elongation of the joint were enhanced to 98% and 126% of the base material levels, respectively.

KEYWORDS:

• Magnesium alloy
• friction stir welding
• twin
• texture
• mechanical properties

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was financial supported by Natural Science Foundation of Jiangsu Province (No. BK20160284) and Fundamental Research Funds for the Central Universities of PR China (No. 2018B22514).