Characterization and quantification of mechanisms influencing the process reliability of Laser Beam Melting by experimental and numerical investigations

通过实验和数值研究对影响激光束熔化工艺可靠性的机制进行表征和量化

• 批准号: 387081806
• 负责人: Professor Dr.-Ing. Nikolaus Andreas Adams
• 金额: --
• 依托单位: Lehrstuhl für Aerodynamik und Strömungsmechanik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/387081806?language=en
• 关键词: Characterization; quantification; mechanisms; influencing; process

The aim of the proposed research project is an advancement of the knowledge on additive manufacturing processes, which employ lasers beams for melting metal powders. The planned investigations will consider the process of cooling and solidification of the molten metal as well as the evaporation of liquid metal, which influences process characteristics and product quality, especially with respect to the occurrence of pores. Also thermally induced residual stresses in vicinity of the heating zone will be analyzed. The focus of the proposed project will be the analysis of the interactions between on one side the selected process parameters (e.g. laser power, scanning speed), the materials employed (heat conductivity, enthalpies of phase changes, powder particle size and shape) and on the other side the fluid- and thermodynamic effects in the melt pool (convection, Marangoni-effect, evaporation, liquid surface topology and laser beam reflections etc.). The obtained insights will allow for more stable beam melting processes and also help to reduce reject rates in production, reduce the number of test runs for new part designs and also allow to shorten the testing program when qualifying new materials.Initially an experimental process analysis is conducted in order to estimate the extent of influence of major process parameters on the process stability. In the following the mechanisms of interaction are investigated in greater detail and are also quantified employing experiments as well as numerical simulations. For the first time the method of smoothed particle hydrodynamics (SPH) will be applied for the simulation of laser beam melting. With SPH fluids and solids are described by Lagrangian particles, which carry properties of the respective phase. Local macroscopic values, such as temperature, are recovered by averaging operations using all particles in vicinity of the position considered. Judging by todays state of technology and our preliminary work, SPH methods will allow for a highly efficient handling of multiple phase changes and of powder layers featuring complex geometries. This will enable simulations of laser beam melting taking into account all relevant physical mechanisms. Experimental investigations will be conducted to validate the numerical method and broaden the knowledge on the melting process. In order to adequately capture rapid transient processes, suitable measurement techniques will be evaluated and adopted to the problem. For investigations of melt pool dynamics and also of the blow-away effect of powder particles from the heating zone due to application of shielding gases and also due to evaporation of the melt, high-speed cameras will be employed.

拟议研究项目的目的是提高增材制造工艺的知识，该工艺采用激光束熔化金属粉末。计划中的研究将考虑熔融金属的冷却和凝固过程以及液态金属的蒸发，这会影响工艺特性和产品质量，特别是气孔的出现。还将分析加热区附近的热致残余应力。拟议项目的重点是分析选定工艺参数之间的相互作用（例如激光功率、扫描速度）、所用材料（导热性，相变的时间，粉末颗粒的大小和形状），另一方面，熔体池中的流体和热力学效应（对流、马兰哥尼效应、蒸发、液体表面拓扑和激光束反射等）。所获得的见解将有助于实现更稳定的光束熔化工艺，并有助于降低生产中的废品率，减少新零件设计的试运行次数，还可以缩短新材料鉴定时的测试程序。首先进行实验工艺分析，以估计主要工艺参数对工艺稳定性的影响程度。在下文中，更详细地研究了相互作用的机制，并且还采用实验以及数值模拟来量化。本文首次将光滑粒子流体动力学（SPH）方法应用于激光熔凝过程的数值模拟。在SPH中，流体和固体由拉格朗日粒子描述，这些粒子携带各自相的属性。局部宏观值，如温度，恢复平均操作使用所有粒子附近的位置考虑。从目前的技术水平和我们的初步工作来看，SPH方法将允许高效地处理多个相变和具有复杂几何形状的粉末层。这将使激光束熔化的模拟考虑到所有相关的物理机制。实验研究将进行验证的数值方法和扩大知识的熔化过程。为了充分捕捉快速瞬态过程，将评估并采用合适的测量技术来解决问题。为了研究熔池动力学以及由于保护气体的应用以及由于熔体的蒸发而导致的粉末颗粒从加热区的吹走效应，将采用高速相机。

项目成果

A Smoothed Particle Hydrodynamics Model for Laser Beam Melting of Ni-based Alloy 718

• DOI: 10.1016/j.camwa.2018.10.020
• 发表时间: 2019-10
• 期刊: Comput. Math. Appl.
• 作者: Johannes Weirather;V. Rozov;Mario Wille;Paul Schuler;C. Seidel;N. Adams;M. Zaeh

Experimental and Numerical Investigations of In Situ Alloying during Powder Bed Fusion of Metals Using a Laser Beam

• DOI: 10.3390/met11111842
• 发表时间: 2021-11
• 期刊: Metals
• 影响因子: 2.9
• 作者: A. Wimmer;B. Yalvac;C. Zoeller;Fabian Hofstaetter;S. Adami;N. Adams;M. Zaeh

In situ alloying: investigation of the melt pool stability during powder bed fusion of metals using a laser beam in a novel experimental set-up

• DOI: 10.1007/s40964-021-00233-y
• 发表时间: 2021-10-31
• 期刊: PROGRESS IN ADDITIVE MANUFACTURING
• 作者: Wimmer, Andreas;Hofstaetter, Fabian;Zaeh, Michael F.
• 通讯作者: Zaeh, Michael F.

Analysis of the phase transformation of AlSi10Mg during Laser Powder Bed Fusion

激光粉床熔融过程中 AlSi10Mg 的相变分析

• DOI: 10.1016/j.procir.2020.09.034
• 发表时间: 2020
• 期刊: Procedia CIRP
• 作者: Wimmer;Lehmann;Schuler
• 通讯作者: Schuler