Investigation of Surface Integrity Induced by Cryogenic Processing of Biomaterials for Improved Functional Performance

This grant provides funding for developing quantitative understanding of surface integrity induced by cryogenic processing of metallic biomaterials through severe plastic deformation (SPD) processes. Engineered surface layers will be produced in selected biomaterials, with preferred nano/ultrafine grain structures, increased hardness and compressive residual stresses, etc., for improved functional performance in biomedical implants and other manufactured components. Cryogenic machining and burnishing processes will be developed to produce surface layers with nano/ultrafine grain structures in selected biomaterials to provide improved wear and corrosion resistance, and compressive residual stresses to offer greater fatigue life. Proposed major project tasks are: (1) Systematic experimental study of surface integrity induced by cryogenic processes to establish the influence of processing parameters on hardness, grain size and residual stresses; (2) Testing of cryogenically-processed components to quantify performance improvement, especially corrosion and wear resistance and fatigue life; (3) Developing hybrid predictive performance models using numerical and analytical methods; (4) Developing optimization methods for performance improvement; and (5) Model validation and refinement. If successful, this project will lead to developing predictive performance models for novel cryogenic manufacturing processes to provide optimal process parameters for producing functionally-superior products from biomaterials. Improved wear and corrosion resistance and enhanced fatigue life are among the most desirable product performance measures expected from optimally designed and performed cryogenic processes. Optimally produced superhard surface layers from cryogenic processing will have the potential to replace hard coating in some applications. The anticipated project findings will also have the potential for producing components in other manufacturing applications for improved performance and life, especially in aerospace and automotive sectors. Significant health and environmental benefits can also be achieved from the implementation of cryogenic processes, which are clean, toxic-free, and pose no adverse health effects.