Multifunctional Surface Engineering using Severe Plastic Deformation in Machining-Based Processes

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The research objective of this award is to understand the physical principles that underlie the evolution of integral regions of refined microstructures on surfaces of bulk metallic materials in a new class of machining-based processes. This elucidation will focus on material systems that can manifest enhanced biological and mechanical properties, when grain-refined to the nanostructured state. Deformation configurations will be designed to allow for the removal of pre-set depths of material, while simultaneously endowing a freshly generated surface with extensive microstructure modification, in a single processing step. First, the process-structure interrelationships will be elucidated by measuring in situ, the thermomechanics of deformation using simultaneous high-speed image correlation and infrared thermography. Then the resulting surface microstructural consequences will be characterized using electron backscattered diffraction and X-ray diffraction. Resulting empirical data will be encapsulated in novel microstructure maps and modeled computationally. Ultimately, the process-structure-performance triad will be completed by measuring the osseointegrative response, corrosion properties and mechanical behavior.If successful, these breakthroughs can enable a practical utilization of newly-discovered functional properties of nanostructured metals, including the extensive proliferation of osteoblasts on nanograined surfaces, their enhanced electrochemical surface passivation, subdued accumulation of radiation damage, etcetera. Here, by focusing on elucidating biological and corrosion properties as a function of microstructures, a convenient manufacturing route is envisaged for endowing multifunctional surfaces on biomedical implants that can be seamlessly integrated with prevailing fabrication schema. Domestic and international collaborations with cutting tool and discrete product manufacturers, as well as with the University of Pittsburgh Medical Center will be leveraged to support the research thrusts and to initiate new outreach initiatives. This award will also support the development of new research-integrated undergraduate/graduate educational initiatives and enhancing participation of underrepresented groups.