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 degrees 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. (C) 2012 Elsevier B.V. All rights reserved.