Determination of phase equilibria in the Co-rich Co–Al–W ternary system with a diffusion-couple technique

High-temperatureγ(FCC)/γ′(L12) Co-Al-W based superalloys

“…It has been shown that γ is metastable in ternary Co-Al-W alloys [8] and therefore long term stability heat treatments were conducted. The samples remained at 800 • C for 1000 h (Fig.…”

Diffusion in FCC Co-rich Co-Al-W Alloys at 900 and 1000 °C

“…Cui et al [17] combined the available experimental data to develop composition-temperature dependent functions to describe the diffusion mobility in the Co-Al system for the FCC phase, following the methods outlined by Agren and co-workers. [18][19][20] The Co-W mobility functions in the FCC phase have been recently assessed by both Zhang et al [21] and Cui et al [22] Specific Al-W binary diffusion couple studies have not been reported, but both Chang et al, [9] Obata et al [23] Kobayashi et al [10] investigated the ternary Co-Al-W system in the FCC phase region in the temperature range from 900 to 1300°C. Other multicomponent diffusion-couple studies were conducted by G¢mez-Acebo et al [24] who studied the Al-Co-Cr-Ni-Ti system and by Minamino et al who studied the Co-Al-CrNi system.…”

“…Initial research on the stability of c¢ in the Co-Al-W system at 900°C were inconclusive: Sato et al initially reported the c¢ phase to be stable while work by Kobayashi and Tsukamoto [10,11] indicated the c¢ was not stable. To resolve this inconsistency, Lass et.…”

Microstructural Development and Coarsening Behavior of γ′ Precipitates in Co–Ni–Al–W-Base ODS Alloys

“…7,8) In CoNiAlW-base ODS alloys, Al and W act as £A forming elements. It is found that mechanical alloying has induced the formation of supersaturated solid solution rather than the fully alloyed powder owing to the extremely low solubility of Al and W in cobalt matrix at room temperature.…”