|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Computational Thermodynamics and Kinetics
||Development of a Thermodynamic Database for a Co Based Superalloy for GT Vanes to Predict the Service Induced fcc-hcp Martensitic Transformation
||Erica Vacchieri, Gabriele Cacciamani, Giacomo Roncallo, Alessio Costa
|On-Site Speaker (Planned)
The thermodynamic calculations are very important to predict and assess material behaviour during service. In GT power plant, old generation Co based superalloys are employed as structural material of vanes because of their good conductibility, TMF resistance and repairability. The vanes after service for an F class plant show several cracks and an increased fragility of the material due to the presence of unexpected hcp phase in the alloy microstructure. An in-house database was developed, starting from literature data. The main 6 element system (C, Co, Cr, Ni, Ta and W) were considered and the 15 binaries and 9 ternaries were assessed looking at all the stable and metastable phases that can be formed in the whole range of composition of each element. The developed database predicts the fcc to hcp phase transformation at a temperature range compatible with service condition and it was validated through laboratory tests.
||Planned: Supplemental Proceedings volume