Structure-Property Correlation in Weld Metals and Interface Regions of Titanium/Steel Dissimilar Joints

In this study, different groove geometries are designed for butt joining of titanium/steel bimetallic plates via explosive welding. The relation between microstructure and mechanical properties are systematically built by microhardness and nanoindentation tests. It has been found that the groove depth of the Cu-V-Ag transition pass has a great influence on the structure and composition of the welds. FeTi and Fe2Ti intermetallics are observed in shallow weld (depth of 0.5 similar to 1.0 mm) near steel base metal and Cu-Ti compounds are observed in deep weld (depth of 3.0 similar to 4.0 mm) near ERTi-1 weld. The joints welded with the groove depth of 1.5 similar to 2.5 mm are crack free. The butt-welded joints have an average tensile strength of similar to 435 MPa and bending angle of similar to 9.5 degrees. The regions dominated by Fe-Ti and Cu-Ti compounds present higher cracking sensitivity, confirmed by the brittle fracture fractography. The strategies for improving the overall mechanical properties in future are suggested.