An Investigation in the Present Phases in a Cast Co-Al-W Cobalt-Base ‎Superalloy Using ‎Experimental Methods and JMatPro Software

Demand for improvements of efficiency in the gas turbines is a driving force for development of ‎new materials generations. Recently, novel Co-Al-W cobalt-base superalloys containing ‎strengthening‎ γ' phase which are capable of using at high temperature have been subject of ‎intense research. The main purpose of this study is to investigate and evaluate present phases in ‎a multi-components Co-Al-W superalloy by both experimental methods and JMatPro software. ‎An alloy belong to this category was cast in VIM furnace. The samples were characterized by ‎SEM-EDS, FE-SEM, XRD and DSC instruments. In the as cast condition, it was found that the ‎matrix phase (‎γ‎) only contained gamma prime phase (‎γ') and MC carbides (riched in Ti and W ‎elements). The JMatPro software simulated precisely the present phases and their formation ‎temperature. Moreover, the software data demonstrated the ‎‏µ‏‎ phase must have presented in the ‎microstructure. According to experimental and simulation results, heat treatment at 900°C for ‎‎48 hours was carried out on the alloy which revealed the tungsten-riched ‎‏µ‏‎ phase in the ‎microstructure. It was found that the formation of the thermodynamically stable ‎‏µ‏‎ phase is ‎restricted depending on the kinetics of the reaction.‎