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

该奖项的研究目标是了解在一种新的基于机械加工的工艺中，块状金属材料表面精细微结构的完整区域的演变所依据的物理原理。这一阐述将集中在当颗粒细化到纳米结构状态时可以表现出增强的生物和机械性能的材料系统。变形配置的设计将允许去除预设深度的材料，同时在单个处理步骤中对新生成的表面进行广泛的微结构修改。首先，通过同步高速图像相关和红外热像仪现场测量变形的热力学，来阐明工艺-结构的相互关系。然后，将使用电子背散射衍射和X射线衍射来表征由此产生的表面微结构后果。由此产生的经验数据将被封装在新的微结构图中，并通过计算进行建模。最终，将通过测量骨整合响应、腐蚀性能和力学行为来完成工艺-结构-性能三位一体的工作。如果成功，这些突破将使新发现的纳米结构金属的功能特性得到实际应用，包括成骨细胞在纳米颗粒表面的广泛增殖、其增强的电化学表面钝化、抑制辐射损伤的累积等。这里，通过重点阐明生物和腐蚀特性作为微结构的功能，设想了一条方便的制造路线，用于在生物医学植入物上赋予多功能表面，该表面可以与流行的制造方案无缝集成。将利用与刀具和离散产品制造商以及匹兹堡大学医学中心的国内和国际合作来支持研究推进并发起新的外展计划。该奖项还将支持制定新的综合研究的本科生/研究生教育举措，并加强代表性不足群体的参与。

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.