Prospects of laser beam welding and friction stir welding processes for aluminum airframe structural applications

Simultaneous improvement of mechanical strength, ductility and corrosion resistance of stir cast Al7075-2% SiC micro- and nanocomposites by friction stir processing

https://iopscience.iop.org/article/10.1088/2053-1591/aafb9f/pdf

Investigation of microstructure and mechanical properties of friction stir welded dissimilar St37/St52 joints

Friction-based welding processes are considered as very efficient solid-state metal joining processes due to soundness of the welded joint with remarkably less energy consumption and environmentall

Friction-based welding processes: friction welding and friction stir welding

Weldability and mechanical properties of AA5083-H112 aluminum alloy and pure copper dissimilar friction spot extrusion welding-brazing

Microstructure evolution and mechanical properties of friction stir spot welded dissimilar aluminum-copper joint

Effect of pin profile on microstructure and mechanical properties of friction stir spot welded Al-Cu dissimilar metals

The ultra-high-strength Al-Zn-Mg-Cu alloy, 7050-T7451, was friction stir welded at a constant tool rotation speed of 600 rpm. Defect-free welds were successfully obtained at a welding speed of 100 mm/min, but lack-of-penetration defect was formed at a welding speed of 400 mm/min. The as-received material was mainly composed of coarse-deformed grains with some fine recrystallized grains. Fine equiaxed, dynamic, recrystallized grains were developed in the stir zone, and elongated grains were formed in the thermomechanically affected zone with dynamic recovered subgrains. Grain sizes in different regions of friction stir-welded joints varied depending on the welding speed. The sizes and distributions of precipitates changed in different regions of the joint, and wider precipitation free zone was developed in the heat-affected zone compared to that in the base material. Hardness of the heat-affected zone was obviously lower than that of the base material, and the softening region width was related to the welding speed. The tensile strength of the defect-free joints increased with the increasing welding speed, while the lack-of-penetration defect greatly reduced the tensile strength. The tensile fracture path was significantly influenced by the position and orientation of lack-of-penetration defect.

Microstructural Characteristics and Mechanical Properties of 7050-T7451 Aluminum Alloy Friction Stir-Welded Joints

Dissimilar copper and brass metals were friction stir welded at a constant welding speed of 80 mm/min. Groove defects were found on the weld surface with a rotation speed of 1000 rpm, and defect-free welds were successfully obtained with rotation speeds ranging from 1200 to 1600 rpm. The base material of copper consisted of an equiaxed α phase, while that of brass was characterized by a coarse α phase containing certain twins and a β′ phase. Onion rings were developed due to the plastic flow of metal induced by mechanical mixing in the stir zone during friction stir welding. The grain size in the heat-affected zone was refined compared with that in the base material at the brass side of the welded joint, while the situation was completely the opposite for the copper side. With increasing rotation speed, grain size in all zones increased. The weld exhibited higher hardness than the base material. There is little change in tensile properties of all the defect-free welded joints with increasing rotation speed, and all the defect-free welded joints were fractured in the lowest hardness region of the welded joint during tensile tests.

Effect of rotation speed on the microstructure and mechanical properties of dissimilar friction stir-welded copper/brass metals

In the present work, the feasibility to repair keyhole left at 316L stainless steel friction stir welding/friction stir processing (FSW/FSP) seam by filling friction stir welding (FFSW) using consumable tools was investigated. Interface behavior and mechanical properties of 316L stainless steel FFSW joints were investigated. The results showed that significant microstructural refinement occurred around the interface of refilled keyhole due to extreme levels of plastic deformation and thermal exposure. No σ phase but few Cr carbides were formed at the refilled joint interface, which would not result in obvious corrosion resistance degradation of 316L stainless steel. Void defects formed at the bottom of the refilled keyhole and the FFSW joint fractured at the interface during the tensile test.

W. L. Zhou

Papers

Microstructure evolution and mechanical properties of friction stir spot welded dissimilar aluminum-copper joint

Effect of pin profile on microstructure and mechanical properties of friction stir spot welded Al-Cu dissimilar metals

Microstructural Characteristics and Mechanical Properties of 7050-T7451 Aluminum Alloy Friction Stir-Welded Joints

Effect of rotation speed on the microstructure and mechanical properties of dissimilar friction stir-welded copper/brass metals

Interface behavior and mechanical properties of 316L stainless steel filling friction stir welded joints