The Determination of Activation Energies and Modeling of Low Temperature (<0.25Tm) Creep Behavior of Alpha, Alpha-Beta and Beta Titanium Alloys

技术：钛合金正在寻找低温（0.25Tm）应用，例如在核废料储存的滴漏屏蔽中，蠕变行为可以发挥重要作用。为了在这些应用中有效地利用钛合金并设计新的合金，需要更好地了解变形机制和微观组织之间的关系。该小组过去的研究重点包括确定β钛合金蠕变的活化能，开发随时间孪晶的晶体学模型，以及确定两相钛合金新变形机制的透射和高分辨率电子显微镜研究。未解决的问题包括时间依赖性双胞胎是如何发生的？α - β钛合金，为什么在α - β钛合金中出现新的变形机制和形貌与变形机制之间的关系。解决这些问题是本次调查的主题。研究包括三维各向异性有限元建模，以确定α相和β相之间的相互作用。该研究的一个成果是建模，该模型结合了钛的变形机制、微观结构和晶体结构。非技术：虽然模型系统是钛合金，但研究结果应适用于其他合金系统，特别是锆合金系统。本次调查涉及研究生和本科生，学生将学习机械测试、透射和高分辨率电子显微镜等实验技能，以及数据分析和技术报告写作技能。此外，将尽一切努力招收少数民族学生。资深研究员是TMS/ASM学生分会的创始指导老师；该分会连续四年获得“卓越分会”奖。本章参加全国专业协会会议，教育来参加大学开放日的高中生，以及部门教育活动。

TECHNICAL: Titanium alloys are finding low temperature (0.25Tm) applications, such as in drip shields for nuclear waste storage where creep behavior can play an important role. For effective use of titanium alloys in these applications and to design new alloys, the relationships between deformation mechanisms and microstructures need to be better understood. Past research highlights by this group include determination of the activation energy for creep of beta titanium alloys, development of crystallographic models for time-dependent twinning, and transmission and high-resolution electron microscopy studies that identify new deformation mechanisms in two-phase titanium alloys. Unresolved issues include how time-dependent twinning occurs in ?alpha titanium alloys, why new deformation mechanisms occur in alpha-beta titanium alloys and the relation between morphology and deformation mechanisms. Addressing these issues is the subject of this investigation. The investigation includes 3-dimensional, anisotropic finite element modeling to determine the interaction between alpha and beta phases. An output of this investigation is modeling that incorporates deformation mechanisms, microstructure, and crystal structure in titanium. NONTECHNICAL: Although the model systems are titanium alloys, the research results should be applicable to other alloy systems, in particular those of zirconium. This investigation involves both graduate and undergraduate students and the students will learn experimental skills such as mechanical testing, transmission and high-resolution electron microscopy, as well as data analysis and technical report writing skills. In addition, every attempt will be made to recruit minority students. The senior researcher is the founding faculty advisor for the TMS/ASM student chapter; the last four years the chapter received the "Chapter of Excellence" award. This chapter participates in national professional society meetings, educating high school students who come to open houses at the university, and the departmental educational activities.