Development of heat resistant near-alpha titanium alloy DAT54

On demand for increasing fuel efficiency of aerocraft, the mass proportion of titanium alloys in material usage in aerospace application have been increasing because they have excellent specific strength. Typically, near-alpha titanium alloys have good high temperature strength among titanium alloys therefore used in compressor part in jet engine. Near-alpha alloy DAT54, Ti-5.8Al-4Sn-3.5Zr-2.8Mo-0.7Nb-0.4Si-0.06C is originally developed as a compressor disk alloy. The chemical composition has been optimized to obtain higher tensile strength than common near-alpha alloy Ti-6242S and IMI834. DAT54 exhibits well balance of low cycle fatigue strength and creep strain rate contributed by the optimum volume fraction of primary alpha, which is 17 % in the transformed beta microstructure. DAT54 has been registered on AMS specification in 2018. In this presentation, effect of the chemical composition and microstructure on mechanical properties is investigated and typical properties of forged disk product will be introduced.