Processing and compressive creep of cast replicated IN792 Ni-base superalloy foams

Nickel-base superalloy foams were created by a casting replication technique where a lightly sintered preform of SrF2 was pressure infiltrated with molten IN792; after solidification of the composite, the salt phase was dissolved with HCl to create 65% open porosity. Room temperature yield strength and stiffness of the IN792 foam compared well with existing models. Monolithic and foam samples were tested under creep conditions at 750 and 850 °C at stresses ranging from 5 to 40 MPa for the foams and from 150 to 650 MPa for the monolithic alloy. Both exhibited power-law creep behavior at high stresses and a transition to viscous flow at lower stresses, which was modeled using equations for dislocation and diffusional creep.