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

点击翻译按钮获取中文摘要

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.