EBSD analysis of the structure of a weld joining a chromium-nickel steel sheet and a titanium alloy sheet through a copper insert

The structure of the different zones of a C02 laser welded joint between a chromium-nickel steel sheet and a titanium alloy sheet, with a copper insert between them, is studied by EBSD analysis. The phase compositions of all the zones have been determined. The weld material has been found to consist of a Cu-based solid solution and unevenly distributed intermetallic particles of different stoichiometric compositions. The heat-affected zones consist of supersaturated iron- and titanium-based solid solutions. After laser welding, the microdeformations of the phase lattices are distributed unevenly over the cross section of the welded joint; namely, the maximum microdeformations and the resulting microstresses are concentrated in the heat-affected zone at the boundary between the weld and the titanium alloy. (paper)