Strain-Transformable Beta Titanium-Base Alloys.
Final technical rept. 1 Jul 69-1 Aug 70,
BATTELLE MEMORIAL INST COLUMBUS OH COLUMBUS LABS
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The objective of the program was to develop a beta titanium alloy which has very good room-temperature formability and capability for precipitation hardening to high strength levels subsequent to forming. The approach used was to develop beta-titanium alloys having strain-transformation capability. This type of beta alloy was found to be extremely formable on the basis of tensile- and Olsen-cup-test evaluations. In comparison with unalloyed titanium in tensile testing, some of the more strain-transformable beta alloys were found to have two to three times the uniform elongation, and in cup testing they showed up to 23 percent improvement cup height. Further, precipitation-hardening treatments aging on some of these same strain-transformable compositions resulted in strength levels of up to 190 ksi with a yield strengthdensity ratio exceeding 1,000,000 inch. The usefulness of such materials in a variety of applications is obvious. Secondary objectives of interest were pursued during the course of alloy development work. The study of compositional effects was of course paramount. In addition, the effects of beta grain size, cooling rate, and deformation rate and the microstructural characteristics of the strain-transformation product were studied. About 20 of the more than 70 alloys studied look promising. Author
- Metallurgy and Metallography
- Fabrication Metallurgy