This SBIR Phase I effort seeks to exploit some of the tremendous benefits that could be attained from a revolutionary new approach to grain refinement in bulk metals. Specifically, preforms of high temperature Ni-base superalloys will be produced in this work with fine grain (FG) to ultra fine grain (UFG) micro-/nano-structures for higher strength. Despite their excellent corrosion resistance and ability to retain strength under extreme operating conditions, the relatively low strength of IN625 and Monel 400 have prevented their more widespread use. Thus, grain refinement methods that incorporate severe plastic deformation (SPD) offer the opportunity to increase the strength of these alloys. Most SPD work to date, however, have only been successfully performed on small, laboratory scale samples given the special (expensive) tools and high pressures needed.. Thus, the present work will demonstrate a new, production level grain refinement technology to produce microstructurally enhanced IN625 and Monel 400 material with higher strength capability for in-space propulsion applications.