Novel Titanium Alloys for High-Strength Fastener Applications

This endeavor was undertaken to mature the development of novel titanium alloys Ti-185, Ti-5553 and modified Ti-6-2-2-2-2 for high-strength fastener applications. These alloys have shown promise as alternatives to the industry’s principal grades Ti-6Al-4V and Beta-C. Ti-185 (1Al-8V-5Fe) and Ti-5553 (5Al-5V-5Mo-3Cr) are meta-stable beta alloys that can be substantially strengthened by solution treatment and aging. This strengthening is achieved by the decomposition of retained beta into alpha + beta along with the decorous distribution of primary alpha phase. Ti-6-22-22 (6Al-2Sn-2Zr-2Mo-2Cr) is an alpha-beta alloy that also is strengthened through heat-treatment. Chemistry and melt methods have been refined to address past segregation issues and thermo-mechanical processing was tailored to optimize mechanical properties. Data generated from laboratory heat treatments on production hot-rolled bars will be presented. Evaluation of roll-formed threads will also be discussed.