|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Gamma (FCC)/Gamma-Prime (L12) Co-Based Superalloys II
||Supersolvus Thermomechanical Processing of Cast Co–Base Superalloys
||Donald Weaver, Katelun Wertz, S. Lee Semiatin, Rajiv Shivpuri, Stephen Niezgoda, Michael Mills
|On-Site Speaker (Planned)
Two–phase, nickel–base superalloys strengthened by high volume fractions of the L12 (γ’) phase are prone to poor hot workability in the coarse–grain, cast condition and are thus typically synthesized via a powder–metallurgy route. By contrast, recently–developed γ–γ’alloys based on the Co–Al–W ternary exhibit a relatively large difference between the solidus and γ’–solvus temperatures that may enable less expensive ingot–metallurgy processing. To this end, plastic flow and microstructure evolution during supersolvus forging of a cast cobalt–base superalloy were investigated to develop fundamental insight into hot–working behavior and to define a processing window to obtain wrought product with a refined gamma grain size. Specifically, isothermal, hot compression tests were conducted at a variety of supersolvus temperatures and strain rates followed by quantitative metallography. The effect of process variables on recrystallization kinetics and recrystallized grain size will also be discussed.