Fundamental consolidation mechanisms during selective beam melting of powders

By Carolin Körner, A. Bauereiß, E. Attar. 2013

284 citations recorded by the source corpus.

During powder based additive manufacturing processes, a component is realized layer upon layer by the selective melting of powder layers with a laser or an electron beam. The density of the consolidated material, the minimal spatial resolution as well as the surface roughness of the resulting components are complex functions of the material and process parameters. So far, the interplay between these parameters is only partially understood. In this paper, the successive assembling in layers is investigated with a recently described 2D-lattice Boltzmann model, which considers individual powder particles. This numerical approach makes several physical phenomena accessible, which cannot be described in a standard continuum picture, e.g. the interplay between capillary effects, wetting conditions and the local stochastic powder configuration. In addition, the model takes into account the influence of the surface topology of the previous consolidated layer on the subsequent powder layer. The influence of the beam power, beam velocity and layer thickness on the formation and quality of simple walls is investigated. The simulation results are compared with experimental findings during selective electron beam melting. The comparison shows that our model, although 2D, is able to predict the main characteristics of the experimental observations. In addition, the numerical simulation elucidates the fundamental mechanisms responsible for the phenomena that are observed during selective beam melting.

Subfields: Automotive Engineering, Computational Mechanics, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/6781791ef34bd3e4ab420fc53a24811dac1b901b

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Automotive Engineering

1. T. Mukherjee
2. T. DebRoy
3. H. Wei
4. Amitava De
5. W. Y. Yeong
6. Swee Leong Sing
7. Wei Zhang
8. Joel Heang Kuan Tan

In Computational Mechanics

1. Wayne E. King
2. S. Khairallah
3. A. Anderson
4. O. Desmaison
5. H. Mindt
6. S. M. Yusuf
7. Hongzhi Duan
8. T. Mukherjee

In Mechanical Engineering

1. T. DebRoy
2. T. Mukherjee
3. H. Wei
4. Amitava De
5. W. Y. Yeong
6. Swee Leong Sing
7. Joel Heang Kuan Tan
8. J. Elmer

Citations in the corpus

• Metal additive-manufacturing process and residual stress modeling (2016, methodology): “considered several dimensionless numbers to characterize powder bed processes [31].”
• Laser powder-bed fusion additive manufacturing: Physics of complex melt flow and formation mechanisms of pores, spatter, and denudation zones (2015, methodology): “The method has been applied in 2D to study single layer [11] and layer upon layer consolidation [12], and shows the importance that the powder packing has on the melt characteristics.”
• Investigation on Porosity and Microhardness of 316L Stainless Steel Fabricated by Selective Laser Melting (2017, background): “They are formed w en either: (a) the energy applied is in ufficient to completely melt the powder feedstock, causing lack of fusion between each adjacent scan and between successive layers [35]; or (b) excessive energy is applied, resulting in spatter ejection [36].”
• Viewpoint: metallurgical aspects of powder bed metal additive manufacturing (2016, background): “The thermal conduction through the powder bed, therefore, competes with the liquid alloy surrounding and melting the powder particles as the liquid penetrates the powder bed from the top surface layer to the previously melted and solidified layers [31].”