Microstructural and mechanical evolution of Al/steel interface with Fe2Al5 growth in resistance spot welding of aluminum to steel

High-velocity impact welding is a kind of solid-state welding process that is one of the solutions for the joining of dissimilar materials that avoids intermetallics. Five main methods have been developed to date. These are gas gun welding (GGW), explosive welding (EXW), magnetic pulse welding (MPW), vaporizing foil actuator welding (VFAW), and laser impact welding (LIW). They all share a similar welding mechanism, but they also have different energy sources and different applications. This review mainly focuses on research related to the experimental setups of various welding methods, jet phenomenon, welding interface characteristics, and welding parameters. The introduction states the importance of high-velocity impact welding in the joining of dissimilar materials. The review of experimental setups provides the current situation and limitations of various welding processes. Jet phenomenon, welding interface characteristics, and welding parameters are all related to the welding mechanism. The conclusion and future work are summarized.

/pdf/high-velocity-impact-welding-process-a-review-21g73r2y10.pdf

High-Velocity Impact Welding Process: A Review

In this study, the relations between interfacial microstructure and mechanical behavior of aluminum alloy sheets and zinc-coated steel sheets magnetic pulse welding (MPW) joints were characterized systematically. MPW joints of aluminum alloy and ungalvanized steel sheets were prepared for comparative analysis. Results showed that some of zinc layer on the galvanized steel was washed away to form metal jet under the high-speed collision. The change of failure mode from interfacial failure to base material fracture due to interfacial microstructure evolution was the fundamental reason for different mechanical behavior of two MPW joints. Because of the difference in element content and the severe plastic shear at the interface, the crystalline grain morphologies and sizes of aluminum and zinc in the transition zone changed. Amorphous structure was also found in the transition zone. The existence of the zinc layer would form brittle and hard phases on the interface, resulting in the generation of welding defects, thereby reducing mechanical properties of the joint.

Mechanical properties and interfacial microstructures of magnetic pulse welding joints with aluminum to zinc-coated steel

Investigation of Collision Surfaces and Weld Interface in Magnetic Pulse Welding of Dissimilar Al/Cu Sheets

The microstructure and mechanical properties of Al/Mg welded joints after heat preservation at different temperatures were examined by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and mechanical property test. The results showed that the treatment has no obvious effects on the morphology of the Al/Mg welding interface, but the morphology of the grain structure on the magnesium alloy side was improved. When the temperature was below 150 °C, there was no significant change in the microstructure and mechanical properties of Al/Mg welded joint. While, the intermetallic compound layer composed of Al12Mg17 was formed at the interface when the temperature was raised to 200 °C. The welding interface generated two intermetallic compound layers composed of Al12Mg17 and Al3Mg2 as the temperature reached to 250 °C. Intermetallic compounds severely affected the strength of the welded joint because of greater brittleness. In order to maintain reliable performance, the use temperature of the Al/Mg welded structural parts should not exceed 150 °C.

The effect of temperature on microstructure and mechanical properties of Al/Mg lap joints manufactured by magnetic pulse welding

Microstructures and mechanical properties of the welded AA5182/HC340LA joint by magnetic pulse welding

Fatigue fracture properties of magnetic pulse welded dissimilar Al-Fe lap joints

Strain rate sensitivity of Al-Fe magnetic pulse welds

Formation mechanism of transition zone and amorphous structure in magnetic pulse welded Al-Fe joint

Magnetic pulse welding (MPW) has attracted widespread attention due to its advantages on joining dissimilar metals. This paper mainly focused on the effect of surface treatment on the weldability and mechanical properties of Al-Fe joints. Two kinds of surface grinding directions, including parallel to welding direction (P2W) and vertical to welding direction (V2W), were designed to prepare MPW joints. Mechanical properties and interface microstructures were systematically analyzed to establish the corresponding relationship between the two. Results showed V2W welded joints presented a wavy-shape interface and had better mechanical properties. The P2W specimens only showed a straight interface, and the element diffusion in the zone of the wave interface was better than that in the zone of the straight interface. The discharge energies affected mechanical properties by changing the interfacial morphology. In addition, the formed jets could be trapped and led to the formation of interfacial waves when the scratch direction did not coincide with the welding direction, contributing to the formation mechanism of wave interface.

Huihui Geng

Papers

Microstructures and mechanical properties of the welded AA5182/HC340LA joint by magnetic pulse welding

Fatigue fracture properties of magnetic pulse welded dissimilar Al-Fe lap joints

Strain rate sensitivity of Al-Fe magnetic pulse welds

Formation mechanism of transition zone and amorphous structure in magnetic pulse welded Al-Fe joint

Effect of surface treatment on the mechanical properties and microstructures of Al-Fe single-lap joint by magnetic pulse welding