Development of Titanium Alloys for Hulls of Deep-Diving Vehicles

摘要

A summary is presented of progress on the alloydevelopment and physical-metallurgy aspects of a program for demonstrating the feasibility of using titanium alloys for hulls of deep-diving vehicles. The program was aimed at obtaining near-alpha-type alloys with good toughness and fabricability at a yield strength of 120 KSI. A minor effort was also made to explore higher-strength alloys. Much of the work was accomplished by contract. Several alloys approached the target properties, but not with consistency. The lack of consistency was associated with inadequate knowledge of optimum mill-processing schedules and physical-metallurgy kinetics. Study of these aspects is now under way. Even though problems remain to be solved, however, the progress to date indicates that it is feasible to use titanium alloys for deep-diving hulls. At least one alloy (Ti-7Al-2Cb-1Ta) can now be considered satisfactory, at a minimum yield strength of 105 ksi, for research-type submersibles. The near future should provide a yield strength between 115 and 120 ksi, plus a choice of additional alloys. (Author)