Dissimilar metal joining of stainless steel and titanium using copper as transition metal

Abstract

Joining of stainless steel and titanium dissimilar metal combination has a specific interest in the nuclear industry. Due to the metallurgical incompatibility, it has been very difficult to produce reliable joints between these metals due to the formation of FeTi and Fe 2 Ti types of intermetallic compounds. The metallurgical incompatibility between both materials is enhanced by the time-temperature profile of the welding process used. Brittle intermetallics (IMCs) are formed during FeTi welding (FeTi and Fe 2 Ti). The present study uses the low thermal heat input process cold metal transfer (CMT), when compared with conventional GMAW, to deposit a copper (Cu) bead between Ti and stainless steel. Cu is compatible with Fe, and it has a lower melting point than the two base materials. The welds were produced between AMS 4911L (Ti-6Al-4V) and AISI 316L stainless steel using a CuSi-3 welding wire. The joints produced revealed two IM layers located near the parent metals/weld interfaces. The hardness of these layers is higher than the remainder of the weld bead. Tensile tests were carried out with a maximum strength of 200 MPa, but the interfacial failure could not be avoided. Ti atomic migration was observed during experimental trials; however, the IMC formed are less brittle than FeTi, inducing higher mechanical properties.

High-Temperature Diffusion Bonding of Ti–6Al–4V and Super-Duplex Stainless Steel Using a Cu Interlayer Embedded with Alumina Nanoparticles

“…When the process was modelled using Thermo-Cal, the results showed that within the bonding temperature range studied (850-900 • C) four binary phases are possible; Cu3Ti2, Cu 2 Ti, Ti 2 Cu, and Cu 4 Ti 3 , as shown in Figure 10A, support the EDS data. Similar observations were reported by Pardal et al [3] who studied dissimilar metal joining of Ti and duplex stainless steel using Cu as a transition metal interlayer. A plot of the Gibbs free energy profile shown in Figure 10C,D indicates that several stable phases are likely to form in the Ti-Cu binary system for the bonding temperature range studied.…”

“…The growth in the demand for higher-performing multicomponent structures and mechanical systems necessitates the combination of these advanced alloys into superstructures containing multiple materials of uniquely differing chemical, thermal, and thermomechanical properties [1,2]. Currently, structures made with materials of similar types are joined using traditional welding technologies such as arc welding [3], laser welding [4], spark plasma welding [5], ultrasonic welding [6], etc. The welding of multiple components of structures is still an area that requires extensive research to identify technologies that are capable of welding dissimilar materials without adverse effects given the differences in the properties of the materials [7].…”

CMT Welding of Titanium and Stainless Steel Using CuSi3 Electrode

“…7: Welding zone microstructure CONCLUSION CMT welding is suitable for joining of heterogeneous materials (Poláková, et al 2017). In Pardal et al 2016, the resulting weld strength values were in the range of approximately 50 - 200 MPa. Pardal heat input evaluates the dominant parameter during the study.…”

“…Good results in the tensile test were achieved only in using the welding parameters designated as a). The d) and e) parameters did not show a sufficient tensile strength due to the formation of fragile compounds between FeTi and Fe2Ti (Pardal 2016). The results of the tensile tests using the welding parameters designated as a) were very similar.…”

“…In area 1, only flexible deformation occurs, area 2 is yield stress and in area 3, plastic deformation occurs. In Pardal et al 2016, the resulting weld strength values were in the range of approximately 50 - 200 MPa. In Chen et al 2014 were the highest values of weld strength of 150 MPa.…”