Tailored Microstructures via Thermoelectric-Magnetohydrodynamics for Additive Manufacturing (TEAM)

通过热电磁流体动力学定制微结构用于增材制造 (TEAM)

• 批准号: EP/W032147/1
• 负责人: Andrew Kao
• 金额: $ 57.58万
• 依托单位: University of Greenwich
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FW032147%2F1
• 关键词: Tailored; Microstructures; via; Thermoelectric; Magnetohydrodynamics

Additive Manufacturing (AM), also termed 3D printing, involves successively adding thin layers of new material formed by melting alloy powders or wires and solidifying them onto prior layers to construct 3D components. This process directly builds intricately shaped parts impossible to create using traditional techniques. Further, AM promises to be both more energy and materials efficient. Potential applications are far reaching, including biomedical, energy and aerospace. However, AM components can suffer from microstructural features that may lead to degraded properties, such as porosity and epitaxial grain growth. Porosity can form from gas bubbles entrained in the solidification front, leading to voids in the final built. Epitaxial grain growth occurs when new grains take on the crystal orientation of the previous layer, producing often undesirable direction dependent properties. We hope to control these features using magnetic fields acting on Thermoelectric (TE) currents.TE effects translate temperature variations at the junction of two conductive materials into electric current. They are well known in common applications such as Peltier coolers, TE generators for waste heat recovery and in thermocouples. In this proposal we aim use the interaction of thermoelectric currents and applied magnetic fields to generate fluid flow in the molten pool of metal that forms material in the AM process. This interaction is called Thermoelectric Magnetohydrodynamics, or TEMHD. Our feasibility studies indicate that TEMHD can transform the microstructure in AM components, preventing the formation of microstructural features such as porosity or epitaxial growth. We will show that thermoelectric effects are a natural and inherent part of AM processes, with high currents forming due to the huge thermal gradients encountered in AM. We will apply controlled external magnetic fields, causing these currents to interact and generate a Lorentz force that drives TEMHD flow. Our preliminary numerical predictions show that even a moderate magnetic field generated by permanent magnets is sufficient for TEMHD to dominate the melt pool hydrodynamics and that the flow magnitude is highly sensitive to the orientation and magnitude of the magnetic field. This sensitivity will enable us to modulate the heat, mass and momentum transport, enabling control of microstructural evolution, including epitaxial growth and gas entrainment. Our vision is to reveal the fundamental mechanisms that TEMHD introduces to AM and to then ultimately develop a pathway to exploit it in industrial applications producing improved and consistent material properties of components.To achieve these goals the investigators will employ state-of-the-art experimental and numerical modelling techniques. High speed in situ synchrotron X-ray radiography of the process will generate data for validation of the numerical model and provide benchmarks for the wider scientific community. The numerical model will capture the complex interactions in the melt pool and provide understanding of the complex physical mechanisms at work. Theoretical predictions from the model will guide the experimental programme, while direct observations will guide the numerical model development. With a validated numerical model, a parametric study of the magnetic field conditions along with key AM processing conditions will be conducted to determine conditions required to produce microstructures that give the properties required for each application. The ability to use TEMHD to design the microstructures will be demonstrated in the experimental programme. Throughout the project we will seek input from our industrial partners, and during the latter stages we will hold a workshop to develop translational pathways for scaling and implementing these techniques to the next generation of AM machines.

增材制造 (AM) 也称为 3D 打印，涉及连续添加通过熔化合金粉末或金属线形成的新材料薄层，并将其固化到先前的层上以构建 3D 组件。该过程直接构建使用传统技术无法创建的复杂形状的零件。此外，增材制造有望提高能源和材料效率。潜在的应用影响深远，包括生物医学、能源和航空航天。然而，增材制造组件可能会受到微观结构特征的影响，从而导致性能下降，例如孔隙率和外延晶粒生长。凝固前沿夹带的气泡可能会形成孔隙，导致最终建成的建筑中出现空隙。当新晶粒呈现前一层的晶体取向时，就会发生外延晶粒生长，从而产生通常不希望的方向依赖特性。我们希望利用作用于热电 (TE) 电流的磁场来控制这些功能。TE 效应将两种导电材料接合处的温度变化转化为电流。它们在帕尔贴冷却器、用于废热回收的 TE 发生器和热电偶等常见应用中众所周知。在本提案中，我们的目标是利用热电流和外加磁场的相互作用，在金属熔池中产生流体流动，从而在增材制造工艺中形成材料。这种相互作用称为热电磁流体动力学，或 TEMHD。我们的可行性研究表明，TEMHD 可以改变增材制造部件中的微观结构，防止形成孔隙或外延生长等微观结构特征。我们将证明热电效应是增材制造过程中自然而然的一部分，由于增材制造中遇到的巨大热梯度，会形成高电流。我们将施加受控的外部磁场，使这些电流相互作用并产生驱动 TEMHD 流动的洛伦兹力。我们的初步数值预测表明，即使是由永磁体产生的适度磁场也足以使 TEMHD 主导熔池流体动力学，并且流动强度对磁场的方向和强度高度敏感。这种敏感性将使我们能够调节热量、质量和动量传输，从而控制微观结构的演化，包括外延生长和气体夹带。我们的愿景是揭示 TEMHD 引入增材制造的基本机制，然后最终开发出一条在工业应用中利用它的途径，从而生产改进且一致的部件材料性能。为了实现这些目标，研究人员将采用最先进的技术实验和数值模拟技术。该过程的高速原位同步加速器 X 射线照相将生成用于验证数值模型的数据，并为更广泛的科学界提供基准。数值模型将捕捉熔池中复杂的相互作用，并提供对工作中复杂物理机制的理解。模型的理论预测将指导实验计划，而直接观察将指导数值模型的开发。通过经过验证的数值模型，将对磁场条件以及关键增材制造加工条件进行参数研究，以确定生产微结构所需的条件，从而提供每种应用所需的特性。使用 TEMHD 设计微观结构的能力将在实验程序中得到证明。在整个项目中，我们将寻求工业合作伙伴的意见，在后期阶段，我们将举办研讨会，以开发将这些技术扩展和实施到下一代增材制造机器的转化途径。

项目成果

In situ characterisation of surface roughness and its amplification during multilayer single-track laser powder bed fusion additive manufacturing

• DOI: 10.1016/j.addma.2023.103809
• 发表时间: 2023-10
• 期刊: Additive Manufacturing
• 影响因子: 11
• 作者: Alisha Bhatt;Yuze Huang;C. L. Leung;Gowtham Soundarapandiyan;S. Marussi;Saurabh Shah;Robert C. Atwood-Robe

Thermoelectric Magnetohydrodynamic Control of Melt Pool Flow During Laser Directed Energy Deposition Additive Manufacturing

• DOI: 10.2139/ssrn.4329316
• 发表时间: 2023-05
• 期刊: SSRN Electronic Journal
• 作者: Xianqiang Fan;Tristan G. Fleming;David Tien Rees;Yuze Huang;S. Marussi;C. L. Leung;R. Atwood

Controlling solute channel formation using magnetic fields

• DOI: 10.1016/j.actamat.2023.119107
• 发表时间: 2023-09
• 期刊: Acta Materialia
• 影响因子: 9.4
• 作者: Xianqiang Fan;N. Shevchenko;C. Tonry;S. Clark;R. Atwood;S. Eckert;K. Pericleous;P. D. Lee

Modulating Meltpool Dynamics and Microstructure using Thermoelectric Magnetohydrodynamics in Additive Manufacturing

• DOI: 10.1088/1757-899x/1281/1/012022
• 发表时间: 2023-05
• 期刊: IOP Conference Series: Materials Science and Engineering
• 作者: A. Kao;C. Tonry;P. Soar;I. Krastiņš;X. Fan;PD Lee;K. Pericleous