Superplastic Forming & Diffusion Bonding of CORONA 5.
Final technical rept. 1 Sep 79-15 Nov 80,
ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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The processing of CORONA 5 Ti-4.5 Al-5 Mo-1.5 Cr to cold-rolled sheet and the subsequent evaluation of this sheet for superplastic formability, diffusion bondability and post-forming heat treatment response is discussed. Two heats of CORONA 5, one of standard oxygen content 0.183 wt and one of low oxygen content 0.085 wt were processed to fine-grained, 0.07 in 1.8 mm sheet and limited characterization of the sheet material conducted. Superplastic properties were determined at 843, 871 and 899 C diffusion bonding parameters were predicted for all three temperatures and evaluated at 871 C. Adequate superplastic properties were observed at all temperatures with the lower temperatures exhibiting better properties. The optimum superplastic forming and diffusion bonding temperature was found to be 871 C, particularly for low oxygen material. Pan forming tests at all three temperatures and the expanded sandwich test at 871 C confirmed these observations. The results of the program have demonstrated that by controlling the oxygen content of CORONA 5 and by processing to a small grain size, a highly desirable combination of SPFDB response and post-forming tensile properties could be obtained and that the alloy is amenable to sheet processing using a continuous-strip process.
- Properties of Metals and Alloys
- Fabrication Metallurgy