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.