On microstructure and mechanical properties of linear friction welded dissimilar Ti–6Al–4V and Ti–6·5Al–3·5Mo–1·5Zr–0·3Si joint

Linear friction welding of dissimilar titanium alloys Ti–6Al–4V (TC4) and Ti–6·5Al–3·5Mo–1·5Zr–0·3Si (TC11) was achieved. Microstructural examination showed that the joint has a clearly identified weld zone and a thermomechanically affected zone on both TC4 and TC11 sides with a clearly identified weld line. In the weld zone of TC4, superfine α grains are dispersed in the β matrix, while in that of TC11, a few recrystallised α grains are observed along the β boundaries. In the thermomechanically affected zone of TC4, both deformed and recrystallised grains exist in the same area, while that of TC11 has a deformed α+β structure. The tensile strength of the joint is comparable to that of the parent TC4 where fracture occurs. The joint microhardness is well related to its microstructure.