Thermodynamic study of single crystal, Ni-based superalloys in the γ plus γ′ two-phase region using Knudsen Effusion Mass Spectrometry, DSC and SEM

Second and third generation single crystal (SX) Ni-based superalloys are considered to be sensitive to microsegregation, incipient melting and microstructural instability. Thus, their thermodynamic properties and stability at high temperatures are of key importance. Vapour composition consisting of four species has been detected in the temperature range 1453-1573 K. This was found after studies of three single crystal Nibased superalloys CMSX-4, CMSX-10K (R) and CMSX-10N (R) using the method of Knudsen Effusion Mass Spectrometry (KEMS). The activities of Ni, Co, Cr, and Al have been determined in the gamma+gamma', two-phase region. A series of Differential Scanning Calorimetry (DSC) measurements were carried out at various ramping up rates to determine phase transition temperatures; the gamma' solvus, the solidus and the liquidus temperature were obtained. Back-scattered Electron Imaging (BEI) and Energy Dispersive Spectroscopy (EDS) measurements were performed and depicted the effect post KEMS for such complex multicomponent systems. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Research on second and third generation single crystal Ni-based superalloys found that their thermodynamic properties and stability at high temperatures are crucial. Vapor composition and activities of Ni, Co, Cr, and Al were determined using Knudsen Effusion Mass Spectrometry, while phase transition temperatures were measured using Differential Scanning Calorimetry. Back-scattered Electron Imaging and Energy Dispersive Spectroscopy depicted the effects of complex multicomponent systems post KEMS.