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.

添加制造(AM)，也称为3D打印，是指将熔化合金粉末或线材形成的新材料连续加入薄层，并将它们固化到先前的层上，以构建3D组件。这一过程直接制造出用传统技术无法制造的形状复杂的零件。此外，AM承诺将提高能源和材料的效率。潜在的应用是深远的，包括生物医学、能源和航空航天。然而，AM组件可能会受到微结构特征的影响，这些特征可能会导致性能退化，如孔隙率和外延晶粒生长。气孔可能形成于凝固前沿的气泡中，导致最终形成的空洞。当新的晶粒呈现上一层的晶体取向时，就会发生外延晶粒生长，从而产生通常不理想的与方向相关的特性。我们希望通过作用于热电(TE)电流的磁场来控制这些特性。TE效应将两种导电材料交界处的温度变化转化为电流。它们在帕尔蒂埃冷却器、余热回收用TE发生器和热电偶等常见应用中广为人知。在这项建议中，我们的目标是利用热电电流和外加磁场的相互作用，在AM工艺中形成材料的金属熔池中产生流体流动。这种相互作用被称为热电磁流体力学，简称TEMHD。我们的可行性研究表明，TEMHD可以改变AM组分的微观结构，防止形成孔洞或外延生长等微结构特征。我们将证明热电效应是AM过程中自然和固有的一部分，由于AM中遇到的巨大温度梯度而形成大电流我们将施加受控的外部磁场，使这些电流相互作用，产生驱动TEMHD流的洛伦兹力。我们的初步数值预测表明，即使是由永磁体产生的中等磁场也足以使TEMHD主导熔池流体动力学，并且流动大小对磁场的方向和大小高度敏感。这种敏感性将使我们能够调节热、质量和动量的传输，从而能够控制微结构的演变，包括外延生长和气体夹带。我们的愿景是揭示TEMHD引入AM的基本机制，然后最终开发出一条在工业应用中利用TEMHD产生改善和一致的组件材料性能的途径。为了实现这些目标，研究人员将使用最先进的实验和数值模拟技术。这一过程的高速现场同步辐射X射线照相术将产生数据，用于验证数值模型，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，并提供对复杂物理机制的理解。模式的理论预测将指导实验计划，而直接观测将指导数值模式的发展。利用经过验证的数值模型，将对磁场条件以及关键的AM加工条件进行参数研究，以确定产生微结构所需的条件，从而提供每种应用所需的特性。使用TEMHD设计微结构的能力将在实验方案中展示。在整个项目中，我们将寻求我们的工业合作伙伴的意见，在后面的阶段，我们将举办一个研讨会，为将这些技术扩展和实施到下一代AM机器开发翻译途径。

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

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

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