Friction stir welding/processing of metals and alloys: A comprehensive review on microstructural evolution

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

Recent progress in surface modification of metals coated by plasma electrolytic oxidation: Principle, structure, and performance

Prospects of laser welding technology in the automotive industry: A review

Wire and arc additive manufacturing : Opportunities and challenges to control the quality and accuracy of manufactured parts

Friction stir welding process of dissimilar metals of 6061-T6 aluminum alloy to AZ31B magnesium alloy

Microstructure characterization and properties of carbon steel to stainless steel dissimilar metal joint made by friction welding

The newly developed aluminum–lithium alloy 2A97 was for the first time joined by laser beam welding in order to meet the ever-increased long-term requirements of aerospace, aviation and armament industries. The weld appearance, microstructure, solute segregation, precipitate behavior, and their relationships with mechanical properties of welded joints were investigated. Sound joints with no crack and a few small porosities are obtained under appropriate heat inputs. As a result of heterogeneous nucleation involving the effect of Zr and Li, a non-dendritic equiaxed zone forms between partially melted zone and fusion zone. The crystal morphologies in fusion zone vary from columnar dendrite to equiaxed dendrite, with the increase of constitutional supercooling. Solute segregation leads to the variations of Cu content in grain interior and boundary, as well as the weak ability of re-precipitation of fusion zone. Most precipitates in the base metal dissolve during welding, and fusion zone contains a decreased quantity of δ ′, β ′, θ ′, and T 1 . The ultimate tensile strength of laser welded joints is 83.4% of that of the base metal, and can meet the application requirements from related industries, but the ductility still needs to be improved. Welding defects and loss of solid solution/precipitation hardened structure lead to the degradation of mechanical properties. Tensile fracture occurs in weld with the brittle intergranular dominated mode and premature failure occurs and extends in the equiaxed zone.

Microstructure and mechanical properties of newly developed aluminum–lithium alloy 2A97 welded by fiber laser

To develop ultrafine grains (UFG) in 6.35 mm thick magnesium alloy, stationary shoulder friction stir processing (SSFSP) with steel and copper backing plates was conducted. Steel backing plate produced uniform fine grains (FG) size of 4.98, 4.75, 4.12 μm in top, middle, bottom of the stir zone (SZ), respectively. In contrast, copper backing plate tailored microstructure from FG (4.1 μm) in the top to UFG (0.96 μm) in the bottom of SZ. SSFSP produced uniform and gradient microstructures, altering temperature gradient by placing steel and copper backing plates, respectively. It is worth to note that UFG microstructure achieved without usage of external cooling, owning to the copper backing plate. Most of the grains found under ~2 μm size in UFG microstructure. FG and UFG microstructures contributed to the enhancement in the ductility and strength, respectively. UFG resulted in significant improvement in hardness and tensile strength by ~80% and 24% of the base material, respectively. The intensity of strong basal texture throughout the thickness found independent of the backing plate type. Microstructure evolutions across the SZ thickness for both processing conditions are discussed using electron back scattered diffraction (EBSD).

Tailoring grain refinement through thickness in magnesium alloy via stationary shoulder friction stir processing and copper backing plate

High speed TIG–MAG hybrid arc welding of mild steel plate

Banglong Fu

Papers

Friction stir welding process of dissimilar metals of 6061-T6 aluminum alloy to AZ31B magnesium alloy

Microstructure characterization and properties of carbon steel to stainless steel dissimilar metal joint made by friction welding

Microstructure and mechanical properties of newly developed aluminum–lithium alloy 2A97 welded by fiber laser

Tailoring grain refinement through thickness in magnesium alloy via stationary shoulder friction stir processing and copper backing plate

High speed TIG–MAG hybrid arc welding of mild steel plate