This specification covers requirements for Ti-5111 alloy titanium rod, bar, and billet intended for use in critical seawater applications, including those affecting safety of nuclear submarine systems (SUBSAFE), where high strength, fracture toughness, and seawater corrosion resistance is required at low to moderate temperatures. Ti-5111, a near-alpha alloy, is well suited for marine applications where strength and high toughness are required. The dynamic toughness (a measure of load and plastic energy dissipation necessary for crack initiation and propagation) of Ti-5111 is nearly three times that of Ti-6Al-4V ELI.