The near-alpha alloy Ti-5Al-1Sn-1Zr-1V-0.8Mo (Ti-5111) was developed in a US Navy sponsored alloy development program for structural submarine applications. The properties of this material do however also make it suitable for other marine uses such as threaded fasteners or for components of marine propulsion systems. The alloy offers intermediate strength and high toughness, together with excellent corrosion resistance and a very high resistance to stress corrosion cracking and hydrogen embrittlement. Published data is now available that characterises the material's performance in most of the above areas. However, although the material is recognised as being weldable, and tensile properties for weld metal are known to be satisfactory, there is very little data that describes the behaviour of welds with respect to fatigue or stress corrosion resistance. As many potential applications have a requirement for joining operations of some kind, this paper describes a program of work designed to make this data available. Chemically matching consumables have been used to produce arc welds via both the MIG and TIG processes. Basic mechanical properties have been determined, and slow strain rate stress corrosion tests carried out to assess the material's resistance to this form of attack. Diffusion bonding trials have also been undertaken to determine the process parameters most suitable for joining the alloy using this technique.
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