This STTR project seeks to develop a new manufacturing system for large-scale, low-cost production of bulk ultrafine grained (UFG) or nanostructured metals in plate, sheet or bar forms. These capabilities will be based on scale-up of a new class of machining-based processes called large strain extrusion machining (LSEM) that has been effective at creating high strength, nanoscale microstructures in a variety of alloy systems. Combining the strengths of M4 Sciences and Purdue University, the project will build on findings that hybrid machining-extrusion processes, based on LSEM constrained chip formation, offer a transformative approach for overcoming the limitations to large-scale production of UFG alloys by Severe Plastic Deformation (SPD) processing. The new hybrid machining processes can impart the large levels of plastic strain needed to effect grain refinement under controlled conditions, while simultaneously providing unprecedented control of the resulting bulk form (size and shape). Based on a strong foundation of preliminary work and intellectual property development, the project seeks to demonstrate LSEM of 4340 steel alloy, integrating systematic processing studies, material characterization, and analysis of energy, cost and equipment requirements.
Keywords: Severe Plastic Deformation, Nanocrystalline, Nanostructured, Microstructure, Ultrafine Grained
