Analysis of Weak Zones in Friction Stir Welded Magnesium Alloys from the Viewpoint of Local Texture: A Short Review

Abstract

Friction stir welding (FSW) is a promising approach for the joining of magnesium alloys. Although many Mg alloys have been successfully joined by FSW, it is far from industrial applications due to the texture variation and low mechanical properties. This short review deals with the fundamental understanding of weak zones from the viewpoint of texture analysis in FSW Mg alloys, especially for butt welding. Firstly, a brief review of the microstructure and mechanical properties of FSW Mg alloys is presented. Secondly, microstructure and texture evolutions in weak zones are analyzed and discussed based on electron backscatter diffraction data and Schmid factors. Then, how to change the texture and strengthen the weak zones is also presented. Finally, the review concludes with some future challenges and research directions related to the texture in FSW Mg alloys. The purpose of the paper is to provide a basic understanding on the location of weak zones as well as the weak factors related to texture to improve the mechanical properties and promote the industrial applications of FSW Mg alloys.

Microstructure Characteristics and Its Effect on the Fracture in the Triple Junction Region of Friction Stir Welded Mg Alloys Subjected to Tension

“…The mechanical properties of FSW joint are lower than that of base material. The decreasing of mechanical properties can be described to the texture of SZ side, favorable for extension twinning and basal slip [ 3 , 15 ]. Based on the mechanical properties, the tensile tests were terminated when the stress level was up to 90% of UTS, and then the specimens were prepared for the microstructure examination.…”

“…However, the hexagonal close packed structure is a negative factor for the formability of Mg alloys [ 2 ]. As a solid-state joining technology, the friction stir welding (FSW) is useful for improving the joining of Mg alloys [ 3 , 4 ]. FSW has been successfully applicated in several Mg alloys systems, such as AZ (Mg–Al–Zn) and AM (Mg–Al–Mn) [ 5 , 6 ].…”

Corrosion behavior of friction stir‐welded AZ31 Mg alloy after plastic deformation

“…[ 1 ] As a solid‐state welding technology, friction stir welding (FSW) has a significant advantage in the joining of Mg alloys. [ 2 ] Severe plastic deformation and full recrystallization occur in the FSW process, [ 3–5 ] which causes significant grain refinement, and forms a strong local texture in the weld zone (WZ) of Mg alloys. [ 4,6–8 ] Then, some regions with a soft‐oriented texture are formed in the WZ and significantly reduced the tensile properties, especially for the yield strength (YS).…”

Influence of Wavy Bending on Microstructure and Mechanical Properties of a Rolled AZ31 Sheet

“…Twin-orientation depends on twin variant selection during deformation [18]. Previous reports indicated that continuous bending, in-plane shear and in-plane compression favorably activate one twin variant in each grain and generate single twin-texture [11][12][13][14][15]19]. It has been reported that change of strain path can promote the activation of multiple twin variations to further randomize twin-texture [20].…”