Quasi-isostatic, Solid-State Forging of a Nanophase Aluminum Alloy for Rocket Turbopump Components

"Quasi-isostatic, solid-state consolidation of a cryogenically prepared nanophase aluminum-7.5 magnesium alloy was successfully accomplished using the patented Ceracon Forging technology. Utilizing a conventional hydraulic forging press to apply highuniaxial pressure (>90ksi/621MPa), at low temperature (<900F/482C), to a confined bed of compressible particles created the unique quasi-isostatic pressure field. The nanophase powder contained therein was consolidated to full theoretical density within20 seconds.Scanning electron microscopy (SEM) and back-scatter electron imaging (BEI) of the rapidly consolidated powder confirmed preservation of a nanophase microstructure consisting of 300 nanometer (nm) size grains. It is believed that the dynamic shear stressintroduced by the quasi-isostatic pressure field destroyed tenacious powder particle surface oxides thereby enabling clean metal surfaces to metallurgically bond. This enabled fabrication of a high quality, ductile nanophase products void of indigenous,property compromising defects common to aluminum metal powders. Tensile ductility of 12% and ultimate strength of 78ksi was demonstrated."