Utilizing local phase transformation strengthening for nickel-base superalloys

Almost 75 years of research has been devoted to producing superalloys capable of higher operating temperatures in jet turbine engines, and there is an ongoing need to increase operating temperature further. Here, a new disk Nickel-base superalloy is designed to take advantage of strengthening atomic-scale dynamic complexions. This local phase transformation strengthening provides the alloy with a three times improvement in creep strength over similar disk superalloys and comparable strength to a single crystal blade alloy at 760 degrees C. Ultra-high-resolution chemical mapping reveals that the improvement in creep strength is a result of atomic-scale eta (D0(24)) and chi (D0(19)) formation along superlattice stacking faults. To understand these results, the energy differences between the L1(2) and competing D0(24) and D0(19) stacking fault structures and their dependence on composition are computed by density functional theory. This study can help guide researchers to further optimize local phase transformation strengthening mechanisms for alloy development. There is an ongoing need to increase the operating temperature of jet engines, requiring new high-temperature materials. Here, local phase transformations at superlattice stacking faults contribute to a three times improvement in creep strength in a Ni-based superalloy.

Automated summary

Research has shown that local phase transformations at superlattice stacking faults contribute to a threefold improvement in creep strength in a nickel-based superalloy. By calculating energy differences and their dependence on composition, researchers can better guide the optimization of strengthening mechanisms for alloys.