|About this Abstract
||2014 TMS Annual Meeting & Exhibition
||High-temperature Gamma (f.c.c.) /Gamma-Prime (L12 structure) Co-Al-W Based Superalloys 2014
||APB Energetics of Co3(Al,W) L12 γ’
||James Saal, Chris Wolverton
|On-Site Speaker (Planned)
With the discovery of Co-based superalloys exhibiting γ/γ’ morphologies, a flurry of research has been performed to determine their high-temperature strength and the effect of alloying on γ’ phase stability. However, fundamental properties for the base Co<SUB>3</SUB>(Al,W) L1<SUB>2</SUB> γ’ remain unknown. We have previously explored with DFT the stability of γ’ and found that at low temperatures, γ’ is a thermodynamically metastable phase. At higher temperatures, entropy-driven effects may potentially stabilize the structure. We have now performed DFT calculations on a fundamental thermodynamic quantity that influences the high-temperature yield strength anomaly, the antiphase boundary (APB) energy. The 100 and 111 APB energies are predicted for Co<SUB>3</SUB>(Al,W) L1<SUB>2</SUB> γ’ and some observations are made as to the unique nature of Co<SUB>3</SUB>(Al,W) L1<SUB>2</SUB> compared to the more commonly studied Ni<SUB>3</SUB>Al. We also predict the effect of a variety of solutes on APB energetics.
||Planned: A print-only volume