Overview of laser and linear friction welding processes for Ti-5553

Light weighting of primary aircraft structures has resulted in ever increasing transition from aluminum alloys to composite materials. Nonetheless, the regions of stress concentration in the composite materials need local reinforcement with metallic structures. Of the various possibilities, titanium alloys offer the highest electrochemical compatibility, with a concomitant high strength to weight ratio, but their high raw material cost and relatively poor machinability and formability are strong motivators to introduce emerging manufacturing technologies that allow a reduction in the buy to fly ratio (i.e. minimized scrap). Hence, the development of cost efficient joining technologies has become an indispensable challenge for the design and near net shape processing of titanium alloy structures. Arc welding, including plasma, has been the traditional joining process used for titanium alloys. However, the high reactivity of titanium with atmospheric gases at elevated temperatures above 400C, especially in the liquid state, has led to the use of high vacuum electron beam welding, particularly for the aerospace industry. With the development of high power solid-state lasers and solid-state linear friction welding, these advanced joining processes have shown significant potential for titanium alloys. In recent years, the Aerospace branch of the National Research Council of Canada (NRC) has conducted some fundamental studies to understand the weldability of a new aerospace titanium alloy, Ti5Al5V5Mo3Cr, using high power solid-state laser and solid-state linear friction welding processes. This presentation will summarize the important progresses achieved in this field. (The authors acknowledge T. Shariff (master) and E. Dalgaard (Ph.D.) and their supervisors Profs. R. Chromik and J.J. Jonas from McGill University; NRC staff E. Poirier, M. Guerin, D. Chiriac, X. Pelletier, J. Baradari and M. Jahazi; Standard Aero Limited staff J. Cuddy and A. Birur.)Peer reviewed: YesNRC publication: Ye