Effect of Alloying and Thermo-Mechanical-Treatment on Anisotropic Creep and Deformation of Ti-alloys

本项目研究了热机械处理（TMT）和合金化对钛合金变形和蠕变各向异性的影响。采用封闭内压薄壁油管叠加轴向载荷，研究了钛合金的各向异性双轴蠕变特性。研究了Ti和Ti- 3Al-2.5V在去应力退火和完全再结晶后的这些行为。添加Al到Ti等合金会导致晶体结构和操作滑移系统的显著改变。冷加工导致Rx材料的等轴组织的晶粒形状各向异性。在不同应力状态和应力水平的双轴加载下，研究这些变量对变形微观结构的影响以及变形各向异性。蠕变机制的转变和潜在变形机制对蠕变各向异性的影响也将得到解决。这些研究对于实际估计这些结构材料的蠕变应变和使用寿命是重要的。该项目涉及当代材料科学领域的基础研究问题，与航空航天、汽车和化学领域的技术相关，其中钛合金用于管状。%%%该计划的一个重要特点是通过培养学生在一个基础和技术上重要的领域的研究和教育的整合。该项目旨在为研究生和本科生提供独特的机会，通过在最前沿的研究环境中积累经验，培养强大的技术、沟通和组织/管理技能。＊＊＊

This project addresses the influence of thermo-mechanical-treatment (TMT) and alloying on deformation and creep anisotropy of titanium alloys. The research involves characterization of anisotropic biaxial creep of Ti alloys using closed-end internally pressurized thin-walled tubing superimposed with an axial load. The approach is to investigate these behaviors in Ti and Ti- 3Al-2.5V following stress-relief anneal and complete recrystallization. Alloying additions such as Al to Ti result in significant modification of crystallographic texture and operating slip systems. Cold-working leads to grain-shape anisotropy of the otherwise equiaxed grain structure of Rx materials. The effects of these variables on deformation microstructures are to be investigated along with deformation anisotropy following biaxial loading under varied stress-states and stress-levels. Transitions in creep mechanisms and the effect of underlying deformation mechanism(s) on creep anisotropy will also be addressed. Such studies are important for realistic estimates of creep strains and life of these structural materials in service.%%% The project addresses basic research issues in a contemporary topical area of materials science with technological relevance in aerospace, automobile, and chemical sectors where Ti-alloys are used in tube form. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area. The project is expected to provide unique opportunities for graduate and undergraduate students to develop strong technical, communication, and organizational/management skills through experiences in a forefront research environment. ***