Microstructure and corrosion behavior of linear friction welded TA15 and TC17 dissimilar joint.

TA15 and TC17 titanium alloys were joined by linear friction welding (LFW) method. The microstructure investigation indicated that the TC17 side welding zone (WZ) was composed of coarse β phases, α phase at grain boundaries and martensite α' phase at the grain interior, while the TA15 side WZ consisted of abundant acicular martensite α' phases and few retained β phases. Electrochemical test result indicated that TA15 base metal (BM) has better corrosion resistance than the TC17 BM. Numerous corrosion pits were formed on the TC17 BM and TC17 side WZ after immersion and salt spray tests. The worse corrosion resistance of the TC17 BM could be attributed to its high content α/β phase boundaries. • TA15 and TC17 titanium alloys were joined by linear friction welding method. • TC17 side welding zone consisted of coarse β phase, α phase and α' phase, while TA15 side welding zone was almost martensite α' phase. • TA15 base metal possessed best corrosion resistance due to lower content of α/β phase boundaries. [ABSTRACT FROM AUTHOR]