Materials World Network: Nanostructuring and Phase Transformations in Beta-Ti Alloys

技术综述：美国加州大学戴维斯分校(UCD)和俄罗斯乌法国立航空技术大学(USATU)的研究人员将研究纳米结构对β-钛合金相变和力学行为的影响。采用机械合金化、放电等离子烧结(SPS)、等通道转角挤压(ECAP)和高压扭转(HPT)等多种材料合成和加工技术来制备纳米结构的β-钛合金。所产生的基本信息将用于建立β-钛合金的纳米结构特征、热稳定性、相变和机械响应之间的关系。利用先进的诊断技术(如扫描电子显微镜、透射电子显微镜)进行的微观结构表征研究，将有助于了解机械合金化、SPS和严重塑性变形(ECAP/HPT)工艺对纳米结构特征的影响，并进一步了解与纳米结构相关的基本现象(如热稳定性、相变和力学行为)。研究纳米结构β-钛合金的力学行为，建立纳米结构特征与力学响应(即弹性模数、强度、延展性)之间的关系。原位扫描电子显微镜和透射电子显微镜力学性能表征的实施将提供对纳米结构β-钛合金动态变形和微观结构变化的直接观察。非技术综述：钛合金具有很高的科学和技术价值，特别是纳米结构的β-钛合金可能表现出高强度和低弹性模量，这在生物医学应用方面非常有吸引力。合作研究计划将有助于建立对纳米结构贝塔钛合金科学的基本理解，并提供对将纳米结构合金的合金成分、微结构和加工历史与机械行为联系起来的基本关系的洞察。即将实施的新方法基于美国加州大学戴维斯分校(UCD)和UFA州立航空技术大学(UFA)之间的互补专业知识和资源，将产生目前缺乏的全面信息，以了解贝塔钛合金和其他材料中纳米结构、相变和机械行为之间的关系。这将最终影响钛材料的发展，这些材料具有在生物医学、航空航天和汽车行业中的应用潜力。研究活动将有助于通过相互访问促进智力合作和学术交流，特别是在UCD和USATU之间研究生和本科生的参与下。这一国际合作还将丰富UCD的外展计划，并将涉及地区大学、学院和K-12。该项目得到了金属和金属纳米结构计划和材料研究部特别计划办公室的支持。

Technical Summary:Researchers at the University of California at Davis, USA (UCD) and the Ufa State Aviation Technical University, Ufa, Russia (USATU) will investigate the influence of nanostructuring on the phase transformations and mechanical behavior in beta-Ti alloys. A variety of materials synthesis and processing techniques including mechanical alloying by cryomilling, spark plasma sintering (SPS), equal-channel angular pressing (ECAP) and high pressure torsion (HPT) will be implemented to synthesize nanostructured beta-Ti alloys. Fundamental information generated will be used to establish the relationship between nanostructuring characteristics, thermal stability, phase transformations, and mechanical response in beta-Ti alloys. Microstructure characterization studies using advanced diagnostic techniques (i.e., SEM, TEM), will provide an understanding of the effect of the mechanical alloying, SPS and severe plastic deformation (ECAP/HPT) processing on nanostructural features, and furthermore understanding of fundamental phenomena (e.g., thermal stability, phase transformations and mechanical behavior) associated with nanostructuring in beta-Ti alloys. Mechanical behavior will be studied to establish the relationship between nanostructural features and mechanical response (i.e., elastic modulus, strength, ductility) in nanostructured beta-Ti alloys. Implementation of in-situ SEM and TEM mechanical characterization will provide direct observation of the dynamic deformation and microstructural changes in nanostructured beta-Ti alloys.Non-Technical Summary:Ti alloys are of scientific and technological interest, and in particular nanostructured beta-Ti alloys may exhibit a high strength with low elastic modulus, which are very attractive for biomedical applications, for example. The collaborative research program will contribute towards the establishment of a fundamental understanding of the science of nanostructured beta-Ti alloys, as well as providing insight into the fundamental relationships that link alloy composition, microstructure and processing history of nanostructured alloys with mechanical behavior. The novel approaches to be implemented, based on complementary expertise and resources between University of California at Davis, USA (UCD) and the Ufa State Aviation Technical University, Ufa, will generate comprehensive information that is currently lacking for understanding of the relationship between nanostructuring, phase transformation and mechanical behavior in beta-Ti alloys and beyond. This, in turn, will ultimately impact the development of Ti materials with potential for applications in the biomedical, aerospace, and automotive industries. The research activities will help nurture intellectual collaborations and academic exchanges through mutual visits, in particular with participation of students at the graduate and undergraduate levels between UCD and USATU. This international collaboration will also enrich UCD's outreach program and will involve regional universities, colleges, and K-12.The project is supported by the Metals and Metallic Nanostructures program and the Office of Special Programs, Division of Materials Research.