Ti-6AL-2CB-1TA-0.8MO Titanium Alloy as a Structural Material for Marine Applications

摘要

A sea-water, stress-corrosion-resistant compositional variation of Ti-7Al-2Cb-1Ta, Ti-6Al-2Cb-1Ta-0.8Mo, has been developed and evaluated as a candidate pressure-hull material. Thick plate produced from pilot heats and production heats of the alloy were found to have good toughness and to be resistant to sea-water stress corrosion and corrosion fatigue. Properties of weldments of the alloy were found to be as good as the base metal and free from sea-water stress corrosion in the as-welded and stress-relieved conditions. A production heat of Ti-6Al-2Cb-1Ta-0.8Mo was evaluated in tension, compression, Charpy V-notch impact, sea-water stress corrosion, low-cycle fatigue, high-cycle fatigue, Bauschinger effect, and stress relaxation. The alloy has a tensile yield strength of 100 ksi in 1-inch thickness and 96 ksi in 2.5-inch thickness. Preliminary data from processing and heat treatment investigations in progress indicate the strength can be raised approximately 5 ksi. The Ti-6Al-2Cb-1Ta-0.8Mo alloy is considered suitable for use as a weldable, high-toughness structural metal for marine applications. (Author)