Influence of Carbon and Oxygen on Some Exploratory Ultrahigh-Strength alpha-beta Titanium Alloys

摘要

An examination was made of the alloys to determine the effect of modifying the oxygen and carbon contents normally employed in titanium alloys on their mechanical properties. A total of 51 exploratory ultrahigh-strength alpha-beta titanium alloys were scrutinized. The results indicated that the alloys with low oxygen content, approximately 0.03% to 0.05% by weight, generally possessed lower yield strengths but good ductility and toughness compared to the alloys with higher oxygen contents at 200,000 psi strength levels. The alloys with the lower oxygen content also responded more readily to the 1150 F aging treatment, causing the yield strength to decrease more substantially than those alloys in the higher oxygen content range of 0.09% to 0.11%. The alloys containing 0.04% to 0.08% oxygen and 0.05% to 0.09% carbon exhibited no definite or predictable change in mechanical properties due to the modified oxygen and carbon. The influence of carbon on ductility and toughness was considerably less than that of oxygen. The optimum alloy, No. 7, containing 0.12% carbon and 0.11% oxygen, displayed a yield strength of approximately 220,000 psi, elongation of 11.9%, and impact strength of 5.9 ft-lb at 1150 F aging temperature. The most effective oxygen plus carbon content for each alloy which would develop the optimum mechanical properties appeared to depend on the alloy and the specified yield strength range. (Author)