Dissimilar FSW of immiscible materials: Steel/magnesium

Abstract

a b s t r a c tThe dissimilar joint between a light metal and a strong metal such as steel, is necessary for reducing the weight of vehicles. Friction Stir Welding (FSW) is a useful process to obtain several kinds of dissimilar joints and many studies have already been reported. However, the joint between steel and magnesium has not been aggressively studied, because it is an immiscible system. Aluminum is one of the most popular alloying elements for magnesium, and the iron-aluminum system has many intermetallic compounds due to their strong interactions. In this study, the Fe-Al intermetallic compound layer was successfully formed at the joint interface between iron and magnesium using aluminum in the magnesium alloys. The joint strength increased with the increasing aluminum content of the magnesium alloy due to the depletion of aluminum at the magnesium side near the interface.

Dissimilar friction stir welding of duplex stainless steel to low alloy structural steel

“…greater hardness) was placed on the advancing side, 10 too great a traverse speed induced top surface groove-like defects due to lack of heat input, 14 and tool pin offset is an important factor to balance tool wear, material flow and weld penetration depth. 11,16 With supporting evidence that FSW could be applied to dissimilar materials, 1,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] some focus was shifted towards dissimilar steel joints. Research in FSW of dissimilar ferrous alloys is immature and continuing to develop, unlike more traditional fusion welding processes.…”

“…[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Extensive work has been carried out to demonstrate the advantages of FSW for a range of metals [24][25][26][27][28][29][30][31][32][33][34][35][36] and a growing amount of work for dissimilar alloys. 1,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Results from FSW of dissimilar materials highlighted the viability of such a process with the majority of reports concluding that high quality, defect-free welds had been produced. Nevertheless, there were a few issues and considerations revealed; the level of material flow is closely linked to weld tool rotational speed, 8 high quality welds were produced when the material requiring t...…”

Application of the 3D Digital Image Correlation to the Analysis of Deformation of Joints Welded With the FSW Method After Shot Peening

“…During FSW method, the material does not melting and the joints is free of typical defects arising in the solidification process, such as precipitation, segregation or gas porosity as is the case with remelting processes. This method can be used to join the materials which are difficult to join using conventional welding [3] such as aluminum alloys [4] copper [5], magnesium alloy [6,7], steels [8] or even dissimilar materials [9,10]. The resulting weld has an equiaxial shape and its grains reach a size of 1-10 µm.…”

A Correlation between the Ultimate Shear Stress and the Thickness Affected by Intermetallic Compounds in Friction Stir Welding of Dissimilar Aluminum Alloy–Stainless Steel Joints

“…Critical technological fields such as air transport, the development of fuel tanks for aerospace applications and the nuclear industry also use FSW to join alloys [3]. The FSW technology opens the possibility of joining materials difficult to weld by traditional fusion processes, such as Mg/Steel [4], Al/Ti [5], Al/Mg [6], and Al/Cu [7] combinations. However, industrial joining between such dissimilar materials still remains a technological challenge because of the numerous parameters which could affect the joint quality.…”