A Concept for the Control of Pore Size in Superalloy Membranes

A new method to adjust the pore size in superalloy membranes is shown, utilizing controlled cooling from solution heat treatment of the solid superalloy. Hereby, the nucleation rate and, thus, the size of the γ'-precipitates can be varied to a large extent. This leads to a corresponding variation in the pore size once the membrane material is produced by directional coarsening of the γ'-phase to an interconnected network and subsequent selective extraction of the γ-phase. Furthermore, it was found that coherent and incoherent γ'-precipitates can be used alike to fabricate superalloy membranes, and yet, result in vastly different pore morphologies. The findings widen the application range of this novel material class.