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

该补助金为定量了解在严重塑性变形（SPD）过程中通过金属生物材料的低温加工产生的表面完整性的研究提供资金。工程表面层将在选定的生物材料中产生，具有优选的纳米/超细晶粒结构、增加的硬度和压缩残余应力等，用于改善生物医学植入物和其他制造部件的功能性能。将开发低温加工和抛光工艺，以在选定的生物材料中产生具有纳米/超细晶粒结构的表面层，以提供改善的耐磨性和耐腐蚀性，以及压缩残余应力，以提供更长的疲劳寿命。主要项目任务是：（1）对低温处理产生的表面完整性进行系统的实验研究，以确定处理参数对硬度、晶粒尺寸和残余应力的影响;（2）对低温处理的部件进行测试，以量化性能改进，特别是耐腐蚀性和耐磨性以及疲劳寿命;（3）使用数值和分析方法开发混合预测性能模型;（4）开发优化方法以提高性能;（5）模型验证和改进。如果成功，该项目将为新型低温制造工艺提供预测性能模型，为从生物材料生产功能优越的产品提供最佳工艺参数。改进的耐磨性和耐腐蚀性以及提高的疲劳寿命是最理想的产品性能措施之一，预期从最佳设计和执行的低温工艺。从低温处理中优化生产的超硬表面层将有可能在某些应用中取代硬涂层。预期的项目研究结果也将有潜力在其他制造应用中生产部件，以提高性能和寿命，特别是在航空航天和汽车行业。低温工艺的实施也可带来显著的健康和环境效益，因为低温工艺清洁、无毒，不会对健康造成不利影响。

This grant provides funding for research on quantitative understanding of the integrity of surfaced produced by cryogenic processing of metallic biomaterials during 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. Major project tasks are: (1) Systematic experimental study of the integrity of surfaced produced 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) Development of hybrid predictive performance models using numerical and analytical methods; (4) Development of optimization methods for performance improvement; and (5) Model validation and refinement. If successful, this project will lead to 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.