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

合金化和形变热处理对钛合金各向异性蠕变和变形的影响

• 批准号: 0412583
• 负责人: K. Linga Murty
• 金额: --
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0412583&HistoricalAwards=false
• 关键词: Effect; Alloying; Thermo; Mechanical; Treatment

This renewal award, a renewal of award DMR-0101309, by the Division of Materials Research in the Directorate for Mathematical and Physical Sciences and the Division of Civil and Mechanical Systems in the Directorate for Engineering to North Carolina State University is to study the influence of thermo-mechanical-treatment (TMT) and alloying on deformation and creep anisotropy of titanium alloys. With this award, Professors Murty and Scattergood will characterize the anisotropic biaxial creep of Ti alloys using closed-end internally pressurized thin-walled tubing superimposed with axial load. The project will 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 the 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 the deformation microstructures will be investigated along with deformation anisotropy following biaxial loading under varied stress-states and stress-levels. This award will address transitions in creep mechanisms and the effect of underlying deformation mechanism(s) on creep anisotropy. Such studies would be important since 'blind' extrapolation of short-term data to low stresses could lead to 'non-conservative' estimates of creep strains and life of these structural materials in-service. The broader impacts of the proposed study involve significance to technologically relevant structural materials in various industries such as aerospace, chemical, transportation, etc., where the reliability of thin-walled tubing is of great concern during in-service exposure under multiaxial loading. The mechanical anisotropy of these materials, while making it relatively complex in predicting the life of structures, constitutes interesting examples for demonstration for both undergraduate and high school students thereby giving them a good feel for real life problems. While the outcome of the proposed study is of direct relevance to appropriate technologies, the study involves fundamental aspects of mechanical metallurgy and mechanics.

该续订合同是DMR-0101309合同的续订合同，由北卡罗来纳州州立大学数学和物理科学理事会材料研究部和工程理事会土木和机械系统部颁发，旨在研究热机械处理（TMT）和合金化对钛合金变形和蠕变各向异性的影响。 有了这个奖项，教授Murty和Scattergood将使用封闭的内部加压薄壁管叠加轴向载荷来表征钛合金的各向异性双轴蠕变。该项目将研究Ti和Ti-3Al-2.5V在消除应力退火和完全再结晶后的这些行为。合金添加剂，如Al到Ti导致晶体织构和操作滑移系统的显着修改。冷加工导致Rx材料的等轴晶粒结构的晶粒形状各向异性。这些变量对变形微观结构的影响将沿着在不同应力状态和应力水平下双轴加载后的变形各向异性进行研究。该奖项将解决蠕变机制的转变和潜在变形机制对蠕变各向异性的影响。这种研究将是重要的，因为“盲目”的短期数据外推到低应力可能会导致“非保守”的估计蠕变应变和寿命的这些结构材料在服务。拟议研究的更广泛影响涉及对航空航天、化工、运输等各个行业中技术相关结构材料的重要性，其中薄壁管的可靠性在多轴载荷下的使用暴露期间是非常重要的。这些材料的力学各向异性，而使其相对复杂的预测结构的寿命，构成有趣的例子，为本科生和高中生演示，从而给他们一个很好的感觉真实的生活问题。虽然拟议研究的结果与适当的技术直接相关，但研究涉及机械冶金和力学的基本方面。