Effect of Structural Changes on Tensile Properties in an Electron Beam Welded and Heat-Treated Ti-Al-Mn Alloy

The high strength-to-weight ratio of titanium alloys has contributed to their extensive use in the aerospace sector. More recently, however, their excellent resistance to corrosion and generally superior mechanical properties have resulted in their increasing use in the chemical industry as well as by the medical profession. Many of these applications involve welded joints and from this point of view the alpha-beta titanium alloys are considerably more difficult to join than the alpha or the beta alloys. Within the alpha-beta family, though many highstrength alloys have been developed to have greater fracture toughness than the standard alloy Ti-6AI-4V, their use has been limited because of poor weldability [1]. This is because of invariably low ductility in the as- welded condition and there is some evidence that, with the addition of increasing amounts of beta stabilizers, the ductility deteriorates further [2]. This has led to the design philosophy in the erstwhile Soviet Union involving the development of titanium alloys with moderate strength but appreciably greater ductility for welded fabrications subjected to complex stresses. While heavier cross-sections can be used for maintaining load-carrying capacity, the ductility would ensure satisfactory weldability [3].