A review: Hybrid welding of high strength materials

Hybrid welding of high-strength materials such as stainless steel, aluminum alloy, and titanium alloy has become more important due to an ever-increasing demand for structural parts with combined properties of lightweight, low cost, enough strength, and energy saving and high performance in adverse environments for automobile, aerospace, petrochemical, and marine applications. Welding of such materials with conventional fusion processes has not always been possible due to wide disparity between their physical and thermal properties, residual stress, as well as the precipitation of thick and brittle intermetallic compounds, IMCs. Mechanical and corrosion properties depend so much on the thickness of IMCs, which conventionally must be less than 10 µm. Although friction stir welding, laser welding, electron beam welding, and ultrasonic welding can give quality hybrid weld with reduced thickness of IMCs as low as 4 µm, their application is limited by size and shape of base metals, need for vacuum environment in the case of electron beam welding, high cost, and special tool requirements. As a result of this, modified fusion arc welding processes remain the most widely applied welding processes in the industries. The improvement in the microstructural properties of hybrid arc fusion welding processes has been observed to achieve quality weld joint with enhanced performance. Comprehensive details of MIG–TIG hybrid welding of some high-strength materials have been developed in the subsequent sections of this review.