Dissimilar Metal Welding and Joint Properties

Dissimilar metal welding encompasses the joining of materials with contrasting thermal, mechanical and chemical characteristics, a capability critical to sectors such as energy generation, aerospace and electronics. Challenges arise from disparities in melting points, thermal expansion coefficients and electrochemical potentials, which can induce residual stresses, brittle intermetallics and galvanic corrosion. A range of approaches—fusion techniques (laser, electron-beam, resistance), solid-state processes (spark plasma, friction stir) and brazing—has been developed to manage heat input, interfacial mixing and phase formation. Joint integrity depends on microstructural control within the fusion zone and the adjacent heat-affected zone, where grain structure, phase distribution and elemental diffusion govern mechanical strength, ductility and corrosion resistance. Innovations in dynamic beam positioning, beam oscillation and novel filler alloys have delivered more uniform interfaces and suppressed deleterious phases. Applications extend from copper–stainless steel joints in cryogenic systems to steel–nickel components in nuclear power, while additive manufacturing of graded bimetallic composites is emerging as a route to seamless integration of dissimilar materials.

Research from Nature Portfolio

Recent studies have examined the influence of process parameters on corrosion resistance and microstructural evolution in copper–stainless steel joints. One investigation explored laser brazing of T2 copper to 304 stainless steel using a Cu–Mn–Ni filler. By varying the angle of laser incidence, researchers delineated transitions between brazed and fully welded modes. Microstructural analysis revealed Cu-rich and Fe-rich phase segregation with Mn and Cr enrichment, while the extent of supersaturated droplet formation in the fusion zone was tied to corrosion pathways. Optimising laser angle mitigated local galvanic couples, enhancing joint durability under corrosive conditions.

Dissimilar Metal Welding and Joint Properties publication trend

The graph below shows the total number of articles in dissimilar metal welding and joint properties across all publications each year (not limited to Nature Index journals).

Technical terms

Fusion zone: The region where base metals and filler material have melted and resolidified, forming the core of the joint.

Heat-affected zone (HAZ): The area adjacent to the fusion zone in which material properties and microstructure are altered by thermal exposure without melting.

Intermetallic compound (IMC): A brittle phase formed by chemical reactions between dissimilar metals, often detrimental to joint toughness.

Diffusion-affected zone (DAZ): The region characterised by atomic interdiffusion between base metals and filler, influencing strength and corrosion behaviour.

Beam oscillation: A controlled lateral movement of the welding beam to modify heat input and promote uniform solidification.

References

1. Effect of laser beam incidence angle on weld formation mechanism and corrosion resistance of T2 copper/304 stainless steel. Scientific Reports (2024).
2. Spark plasma welding joining of copper- AISI4140 steel: Microstructures and mechanical properties. Heliyon (2023).
3. Effect of beam oscillation on porosity and intermetallics of electron beam welded DP600-steel to Al 5754-alloy. Journal of Materials Processing Technology (2019).
4. Qualification of electron-beam welded joints between copper and stainless steel for cryogenic application. IOP Conference Series Materials Science and Engineering (2015).
5. Characterization of a Bimetallic Multilayered Composite “Stainless Steel/Copper” Fabricated with Wire-Feed Electron Beam Additive Manufacturing. Metals (2021).
6. Microstructure investigation on the fusion zone of steel/nickel-alloy dissimilar weld joint for nozzle buttering in nuclear power industry. Welding in the World (2021).
7. Influence of Beam Power on Structures and Mechanical Characteristics of Electron-Beam-Welded Joints of Copper and Stainless Steel. Metals (2022).
8. Application of Dynamic Beam Positioning for Creating Specified Structures and Properties of Welded Joints in Electron-Beam Welding. Materials (2020).