Advanced Processing of a Near Beta Titanium Alloy

钛合金由于具有高的比强度和优异的耐腐蚀性，在航空航天、化工、生物医学等行业得到了广泛的应用。对于下一代更轻、更节能的飞机结构，从减轻重量和机械性能的角度来看，与使用最广泛的合金Ti-6Al-4V相比，在机身、转向架梁、襟翼导轨、短舱、挂架和起落架组件中使用高强度近钛合金将具有成本效益。主要的航空制造商，如空中客车和波音公司已经开始使用锻造近钛合金作为起落架部件。近钛合金具有广阔的应用前景。然而，虽然已经对近钛合金设计进行了大量研究，但是从工业制造的角度，特别是在诸如焊接、成形和增材制造（AM）的工艺期间，几乎没有做任何工作来理解微观结构-机械性能的相关性。近钛合金的性能高度依赖于其内部微观结构，其通常由多相和沉淀物组成。这些析出物的体积分数、尺寸、形态和分布可以显著影响近钛合金的机械性能。因此，全面而详细地了解相变和微观结构演变对于优化各种应用的机械性能至关重要。我建议使用各种工业制造工艺，如连接，成型和AM，对近钛合金进行详细研究。本研究计画未来五年之主要目标为：（1）针对各种工业制造方法，进行制程参数之最佳化。(2)学习如何通过不同的热加工和热机械加工来控制微结构。(3)定量研究单个显微组织特征，并将其与相应的机械性能相关联。

Summary of ProposalTitanium alloys have been widely used in the aerospace, chemical, and biomedical industries due to their high specific strength and excellent corrosion resistance. For the next generation of lighter and energy-efficient aircraft structures, the use of high strength near- Ti-alloys in the fuselage, bogie beam, flap track, nacelles, pylon, and la195nding gear assemblies will be cost effective from the perspective of weight reduction and mechanical properties compared to the industry workhorse Ti-6Al-4V, the most widely used + alloy. Major aerospace manufacturers like Airbus and Boeing have started to use forged near- Ti-alloys as landing gear components. It is expected that near- Ti-alloys will gain wider applications in the future. However, while significant research has been conducted on near- Ti-alloy design, little work has been done to understand the microstructure-mechanical properties correlations from the industrial manufacturing point of view, especially during processes such as, welding, forming, and additive manufacturing (AM).The properties of near- Ti-alloys are highly dependent on their internal microstructure, which often is composed of multiple phases and precipitates. The volume fraction, size, morphology, and distribution of these precipitates can significantly influence the mechanical properties of the near- Ti-alloys. Therefore, a complete and detailed understanding on phase transformations and microstructural evolution are crucial to optimize the mechanical properties for various applications. I am proposing a detailed study on a near- Ti-alloy using various industrial manufacturing processes, such as joining, forming, and AM. The main objectives of this proposed research program for the next five years are:(1) To optimize the processing parameters for various industrial manufacturing methods.(2) To learn how to control the microstructures through different thermal and thermo-mechanical processing. (3) To study individual microstructural features quantitatively and correlate it to the corresponding mechanical properties.