The physical, mechanical and corrosion properties of titanium and alloys favorably impact current U.S. Navy ship design requirements for increased reliability with reduced maintenance and reduced weight. Based on the excellent erosion-corrosion properties of titanium, commercially pure grades are used extensively for seawater pumps, cooling and piping applications. For high-strength critical applications, the U.S. Navy developed and certified Ti-6Al-2Cb-1Ta-0.8Mo (Ti-100) alloy for pressure hulls on deep submersibles. Ti-100 utility suffered from high cost of alloying additions, low product yields, and lack of commercial market. Ti-5Al-1Sn-1Zr-1V-0.8Mo (Ti-5111) alloy was developed as a lower cost, more producible alternative alloy. The results of testing conducted to characterize the strength, fracture toughness, fatigue, and seawater corrosion/stress corrosion resistance properties of the Ti-5111 alloy demonstrated that Ti 5111 alloy and welds possess high strength, good fracture toughness and excellent resistance to seawater corrosion suitable for machinery and structural applications in naval ships and submarines.
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