Heat Treatment Effect on the Structure and Properties of Electron Beam Welded Joints Made of High-Alloy Titanium

S.G. Hryhorenko, S.W. Achonin, W.Ju. Belous, R.W. Selin 2017.05.17 by Marek Dragan The article presents the specific formation of a joint made of high-strength high-alloy titanium alloy (? + ß) subjected to electron beam welding in vacuum. Tests involved the use of Ti-Al-Mo-VNb-Cr-Fe-Zr specimens obtained through electron melting. The research involved tests focused on the effect of a welding thermal cycle and post-weld heat treatment on structural-phase transformations in the weld metal and HAZ of welded joints. It was revealed that the weld metal and HAZ were composed of a structure dominated by the metastable phase ß, which led to the reduction of plasticity and toughness indexes. The improvement of the structure and mechanical properties of electron beam welded joints required the performance of post-weld heat treatment. The best mechanical characteristics of welded joints were obtained after a heat treatment performed in a furnace (annealing at ?=900°C for 1 hour and cooling along with the furnace) favouring the obtainment of an almost homogenous structure and the decomposition of metastable phases in the weld and HAZ.