Dissimilar Metal Joining Techniques in Titanium and Stainless Steel Systems

The joining of dissimilar metals such as titanium and stainless steel presents inherent challenges due to the tendency to form brittle intermetallic compounds (IMCs) at the interface, undermining mechanical integrity. A diverse array of techniques has emerged to mitigate these issues: fusion welding methods utilising hybrid heat sources or controlled heat input improve microstructural control; solid-state approaches such as diffusion bonding and transient liquid phase bonding circumvent melting to limit IMC growth; and laser-based additive manufacturing routes enable graded transitions through sequential deposition. Strategic use of interlayers, including copper, nickel, silver and refractory metals, modifies diffusion pathways and suppresses deleterious phases. Recent advances focus on process optimisation, interfacial engineering and real-time monitoring to achieve high-strength, corrosion-resistant joints. Such developments are critical for aerospace, nuclear, petrochemical and biomedical applications where the combination of low density, high strength and corrosion resistance is paramount. This summary synthesises the current state of research across multiple joining strategies.

Research from Nature Portfolio

Recent studies have demonstrated the effect of controlled heat input in hybrid laser and Cold Metal Transfer welding of commercially pure titanium to carbon steel, revealing that lower energy settings reduce the size and thickness of FeTi and Fe₂Ti intermetallic layers, thereby elevating tensile strength to over 420 MPa while minimising cracking. In parallel, advancements in laser additive manufacturing have introduced a multi-layer transition sequence (Ti→V→Cr→Fe→SS316) to fabricate crack-free graded structures. This approach effectively prevents direct Ti–Fe intermetallic formation, yields uniform hardness distribution and maintains structural integrity, signalling the potential for integrated multi-material components.

Dissimilar Metal Joining Techniques in Titanium and Stainless Steel Systems publication trend

The graph below shows the total number of articles in dissimilar metal joining techniques in titanium and stainless steel systems across all publications each year (not limited to Nature Index journals).

Technical terms

Intermetallic compound (IMC): A brittle phase formed at metal interfaces through diffusion of constituent elements.

Diffusion bonding: Solid-state joining process using temperature and pressure to promote atomic diffusion across interfaces.

Cold Metal Transfer (CMT): Low-heat input welding technique that uses controlled short circuits to reduce thermal distortion.

Transient Liquid Phase (TLP) bonding: Solid-state method employing a melting interlayer that solidifies isothermally to form a bond.

Laser additive manufacturing: Layer-by-layer fabrication using a laser to fuse metal powders, enabling graded or multi-material structures.

Interlayer: A material placed between two base metals to modify interfacial reactions and suppress brittle phase formation.

References

1. Effect of heat input on interfacial characterization of the butter joint of hot-rolling CP-Ti/Q235 bimetallic sheets by Laser + CMT. Scientific Reports (2021).
2. Investigation on Ti6Al4V-V-Cr-Fe-SS316 Multi-layers Metallic Structure Fabricated by Laser 3D Printing. Scientific Reports (2017).
3. A Review on Diffusion Bonding between Titanium Alloys and Stainless Steels. Advances in Materials Science and Engineering (2018).
4. The Effect of Laser Offset Welding on Microstructure and Mechanical Properties of 301L to TA2 with and without Cu Intermediate Layer. Metals (2020).
5. Current Trends in Dissimilar Diffusion Bonding of Titanium Alloys to Stainless Steels, Aluminium and Magnesium. Journal of Manufacturing and Materials Processing (2020).