High-strength titanium alloy/steel butt joint produced via friction stir welding

For the first time, defect-free butt welds of titanium alloy/steel were successfully fabricated via friction stir welding. Joints were produced by employing rotation speed varied at 600 and 950 rpm with a constant travel speed of 47.5 mm/min. An increasing of rotation speed leads to thicken the intermetallic compound layer, coarsen the grain size and thus decrease the joint microhardness. Thanks to the solid-state joining process, only a thin FeTi layer was formed at the interface even rotation speed increased to 950 rpm. As a result, all obtained joints fractured at the base steel material. The work carried out clearly shows the good weldability of titanium alloy to steel via friction stir welding. Crown Copyright (C) 2018 Published by Elsevier B.V. All rights reserved.