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.

Steel, aluminium and magnesium are important engineering materials owing to their excellent mechanical properties. However, their applications are limited due to inadequate corrosion resistance. Various coatings and improvement technologies are used to enhance the corrosion resistance in industry and consumer products. Fabrication of hydrophobic surfaces is a very interesting approach to anticorrosion in that it is derived from the superhydrophobicity found in nature. This paper is a general review of the methods to construct a superhydrophobic surface, i.e. a thin coating layer, on various metallic materials surfaces to enhance their anticorrosion property, providing an introduction of the superhydrophobicity, including theory, properties and fabricating methods. Different methods including spray technique, laser ablation, electrochemical deposition, micro-arc oxidation and etching routes were discussed.

Externally physical fields such as stress field, electric field and magnetic field have been demonstrated influence the equilibria and kinetics of solid-state transformations in metals and alloys. This review focuses on the effects of externally physical fields on the aging precipitation of aerospace Al alloys including 2xxx Al-Cu alloys, 7xxx Al-Zn-Mg alloys as well as the advanced Al-Li alloys. While the η’ phase in Al-Zn-Mg alloy and the T₁ phase in Al-Li alloy showed no obvious stress-orientating effect, the precipitation of θ’ phase in Al-Cu alloy showed obvious stress-orientating effect depending on the applied stress direction. Regarding precipitation kinetics, aging under stress field, electric field and magnetic field all can enhance the aging precipitation of aerospace Al alloys. The understanding of the effects of externally physical field on the aging precipitation in Al alloys is very preliminary. It appears that while the stress field acts on the thermally activated transformation, the athermal effect associating with electromigration of electromagnetic field has been considered responsible for the enhanced aging precipitation.

Bipolar plates are a major part of fuel cells, which are a clean and recyclable energy source. This study was carried out with two dies for a bipolar plate forming investigation with the magnetic pulse method: a bipolar plate die and a 10-channel die. With the bipolar plate die, the forming of bipolar plates with a Cu110 sheet and a Grade 2 Ti sheet indicated that the bipolar plate die needed optimization for a full replication. The obtained maximum average depth percentage was 86% for a Cu110 sheet, while it was 54% for a Grade 2 Ti sheet in this study. A further increase of the depth percentage is possible but requires a much higher capacitor bank energy. The increase of the capacitor bank energy would result in severe tearing, while the depth percentage increase was little. The primary current and flyer velocity were measured at various capacitor bank energies. With the 10-channel die, the die parameters’ effect on metal sheet forming was investigated with a Cu110 sheet and an SS201 sheet. The draft angle had a significant effect on the replication of the die surface. The full replication was achieved for channels with proper parameters with both a Cu110 sheet and an SS201 sheet. Therefore, the bipolar plate die could be optimized based on the 10-channel die results.