Laser-based Additive Manufacturing of Metal Parts from Powder in Microgravity

微重力下粉末金属零件的激光增材制造

• 批准号: 456663377
• 负责人: Professor Dr.-Ing. Andrè Katterfeld
• 金额: --
• 依托单位: Institut für Transport- und Automatisierungstechnik (ITA)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/456663377?language=en
• 关键词: Laser; based; Additive; Manufacturing; Metal

During any deep space mission (e.g. flying to Mars), spare parts are needed to keep the spacecraft operational. Instead of manufacturing spare parts on Earth and bringing them along, parts can be produced during the mission by additive manufacturing (AM). By utilizing AM, the total mass of the mission is greatly reduced and its safety is increased, since it is possible to react to component failure more flexibly.Multiple AM processes have been researched that work in microgravity. However, no AM process that works in microgravity has been researched that is capable of simultaneously being able to produce net shapes solely by AM, repairing surfaces, and producing different alloys. Laser Metal Deposition (LMD) is capable of achieving these goals. During the LMD process, a laser beam creates a melting pool on the work piece. Simultaneously, a fluidized metal powder is injected into the melting pool. When the laser beam traverses the work piece, the melting pool solidifies thus creating an elevated structure on the work piece.The research goal is to develop and characterize the LMD process in microgravity. The characterization of the LMD process is achieved by analyzing the manufactured specimens. The following attributes of the specimens are analyzed: geometry, metallography, hardness and uniaxial tensile strength. The major process parameters that are varied during the LMD process are the beam power, the powder attributes, and the feed rate.To achieve the research goal two primary objects have to be accomplished: the powder feeding and the laser-based creation of the melting pool must work in microgravity. For both primary objects fundamental research under microgravity conditions is necessary. Microgravity is achieved by the Einstein-Elevator - a novel drop tower that has a much higher repetition rate than conventional conveyors and thus allows testing a higher number of specimens.Within the research project, two powder feeder prototypes are built and tested in the Einstein-Elevator: a discontinuous and a continuous one. The development of the prototypes is aided by performing numerical CFD and DEM simulations to analyze the gas and particle behavior under microgravity.Laser based melting of metals in microgravity is researched by integrating a laser into the Einstein-Elevator. To operate this laser in the Einstein-Elevator, a process chamber is required that provides an inert gas atmosphere. Furthermore, a portable energy source and a heat exchanger is integrated into the Einstein-Elevator.

在任何深空使命（例如飞往火星）期间，都需要备件来保持航天器的运行。代替在地球上制造备件并将其沿着，部件可以在使命期间通过增材制造（AM）生产。通过利用增材制造，使命的总质量大大减少，其安全性增加，因为它可以更灵活地对部件故障作出反应。然而，没有研究过在微重力下工作的AM工艺，其能够同时能够仅通过AM产生净形状，修复表面并产生不同的合金。激光金属沉积（LMD）能够实现这些目标。在LMD过程中，激光束在工件上创建熔池。同时，将流化的金属粉末注入熔化池中。当激光束穿过工件时，熔池凝固，从而在工件上形成一个隆起的结构。研究目标是在微重力下开发和表征LMD工艺。LMD过程的表征是通过分析制造的试样来实现的。分析了试样的几何形状、金相组织、硬度和单轴拉伸强度。激光熔池成形过程中的主要工艺参数是激光束功率、粉末属性和进给速率，要实现这一研究目标，必须实现两个主要目标：粉末进给和基于激光的熔池成形。对于这两个主要物体，都需要在微重力条件下进行基础研究。Einstein-Elevator是一种新型的落塔，其重复率比传统的输送机高得多，因此可以测试更多数量的样品。在该研究项目中，制造了两个粉末进料器原型，并在Einstein-Elevator中进行了测试：一个是不连续的，一个是连续的。通过数值计算流体动力学和离散元模拟来分析微重力条件下气体和颗粒的行为，从而辅助原型的开发。通过将激光器集成到爱因斯坦电梯中，研究了微重力条件下基于激光的金属熔化。为了在爱因斯坦升降机中操作该激光器，需要提供惰性气体气氛的处理室。此外，便携式能源和热交换器集成到爱因斯坦电梯中。