TCP suppression in a rutheniumm bearing single-crystal nickel-based superalloy

Ruthenium suppresses the precipitation of deleterious topologically close-packed (TCP) phases in high refractory content single-crystal nickel-based superalloys. The effectiveness of ruthenium as a TCP suppressant appears to be the net effect of its limited solubility in the TCP phase, a lower density of structural growth ledges for atomic attachment at the TCP/matrix interface, and destabilization of the gamma' phase at elevated temperatures. These characteristics combine to limit the growth rates of TCP precipitates and decrease the driving force for their precipitation. Destabilization of the gamma' phase upon the addition of ruthenium is particularly potent due to the sensitivity of the rhenium content in the gamma matrix to changes in the gamma' volume fraction.