scholarly journals Thermo-Fluid-Dynamic Modeling of the Melt Pool during Selective Laser Melting for AZ91D Magnesium Alloy

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4157
Author(s):  
Hongyao Shen ◽  
Jinwen Yan ◽  
Xiaomiao Niu
Keyword(s):  
Temperature Distribution ◽  
Magnesium Alloy ◽  
Selective Laser Melting ◽  
Laser Power ◽  
Large Temperature ◽  
Fe Model ◽  
Laser Melting ◽  
Az91d Magnesium Alloy ◽  
Melt Pool ◽  
Flow Activity

A three dimensional finite element model (FEM) was established to simulate the temperature distribution, flow activity, and deformation of the melt pool of selective laser melting (SLM) AZ91D magnesium alloy powder. The latent heat in phase transition, Marangoni effect, and the movement of laser beam power with a Gaussian energy distribution were taken into account. The influence of the applied linear laser power on temperature distribution, flow field, and the melt-pool dimensions and shape, as well as resultant densification activity, was investigated and is discussed in this paper. Large temperature gradients and high cooling rates were observed during the process. A violent flow occurred in the melt pool, and the divergent flow makes the melt pool wider and longer but shallower. With the increase of laser power, the melt pool’s size increases, but the shape becomes longer and narrower. The width of the melt pool in single-scan experiment is acquired, which is in good agreement with the results predicted by the simulation (with error of 1.49%). This FE model provides an intuitive understanding of the complex physical phenomena that occur during SLM process of AZ91D magnesium alloy. It can help to select the optimal parameters to improve the quality of final parts and reduce the cost of experimental research.

Thermal Modeling of 304L Stainless Steel for Selective Laser Melting: Laser Power Input Evaluation

2017 ◽  
Author(s):  
Diego Augusto de Moraes ◽  
Aleksander Czekanski
Keyword(s):  
Stainless Steel ◽  
Temperature Distribution ◽  
Selective Laser Melting ◽  
Laser Power ◽  
Laser Scanning ◽  
Power Input ◽  
304L Stainless Steel ◽  
Laser Melting ◽  
Powder Bed ◽  
The Impact

Selective Laser Melting (SLM) process is a Powder Bed Fusion (PBF) technique, which has shown significantly growth in the recent years. The demand for this process is justified by the versatility and ease in manufacturing the parts from 3D models as well for the increased complexity of engineered parts generated from topology or shape optimization. Automotive, aerospace, medical and aviation industries are taking great advantage of this process due the unique geometry characteristics found in the components. To enhance the benefits of SLM, a vital task is to analyze the laser power input impact on the temperature distribution through the powder bed, important for posterior residual stresses analysis. The Finite Element Method proposed in this study is a transient thermal model, able to predict temperature distribution through different sections of the powder bed when performing a single track of the laser scanning. Furthermore, the impact of the laser power input is carried out utilizing SS 304L, a low cost Stainless Steel alloy that can be employed in the SLM process, in order to determine the influence on the temperature distribution along the different cross sections.

scholarly journals Selective Laser Melting of Pre-Alloyed NiTi Powder: Single-Track Study and FE Modeling with Heat Source Calibration

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7486
Author(s):  
Stanislav V. Chernyshikhin ◽  
Denis G. Firsov ◽  
Igor V. Shishkovsky
Keyword(s):  
Heat Source ◽  
Thermal Behavior ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Laser Power ◽  
Scanning Speed ◽  
Fe Modeling ◽  
Single Track ◽  
Laser Melting ◽  
Melt Pool

Unique functional properties such as the low stiffness, superelasticity, and biocompatibility of nickel–titanium shape-memory alloys provide many applications for such materials. Selective laser melting of NiTi enables low-cost customization of devices and the manufacturing of highly complex geometries without subsequent machining. However, the technology requires optimization of process parameters in order to guarantee high mass density and to avoid deterioration of functional properties. In this work, the melt pool geometry, surface morphology, formation mode, and thermal behavior were studied. Multiple combinations of laser power and scanning speed were used for single-track preparation from pre-alloyed NiTi powder on a nitinol substrate. The experimental results show the influence of laser power and scanning speed on the depth, width, and depth-to-width aspect ratio. Additionally, a transient 3D FE model was employed to predict thermal behavior in the melt pool for different regimes. In this paper, the coefficients for a volumetric double-ellipsoid heat source were calibrated with bound optimization by a quadratic approximation algorithm, the design of experiments technique, and experimentally obtained data. The results of the simulation reveal the necessary conditions of transition from conduction to keyhole mode welding. Finally, by combining experimental and FE modeling results, the optimal SLM process parameters were evaluated as P = 77 W, V = 400 mm/s, h = 70 μm, and t = 50 μm, without printing of 3D samples.

scholarly journals Effect of Laser Parameters on Processing of Biodegradable Magnesium Alloy WE43 via Selective Laser Melting Method

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2623
Author(s):  
Jan Suchy ◽  
Miroslava Horynová ◽  
Lenka Klakurková ◽  
David Palousek ◽  
Daniel Koutny ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Selective Laser Melting ◽  
Laser Power ◽  
Stable Process ◽  
Scanning Speed ◽  
Process Window ◽  
Laser Melting ◽  
Weld Deposit ◽  
Thin Walls ◽  
Alloy We43

The global aim of the theme of magnesium alloy processing by the selective laser melting technology is to enable printing of replacements into the human body. By combining the advantages of WE43 magnesium alloy and additive manufacturing, it is possible to print support structures that have very similar properties to human bones. However, printing magnesium alloy parts is very difficult, and the printing strategies are still under development. Knowledge of weld deposit behaviour is needed to design a complex printing strategy and still missing. The main aim of the manuscript is the find a stable process window and identify the dependence of the weld deposit shape and properties on the laser power and scanning speed. The range of the tested parameters was 100–400 W and 100–800 mm/s for laser power and scanning speed. The profilometry and light microscopy were used to verify the continuity and shape evaluation. The microhardness and EDX analysis were used for the detailed view of the weld deposit. The manuscript specifies the weld deposit dimensions, their changes depending on laser power and scanning speed, and the continuity of the weld tracks. The stable weld deposits are made by the energy density of 5.5–12 J/mm2. Thin walls were also created by layering welds to determine the surface roughness scattering (Ra 35–60) for various settings of laser power and scanning speed.

scholarly journals Edge and corner effects in selective laser melting of IN 625 alloy

2020 ◽  
Vol 7 ◽  
pp. 8 ◽  
Author(s):  
Gheorghe Matache ◽  
Mihai Vladut ◽  
Alexandru Paraschiv ◽  
Raluca Mihaela Condruz
Keyword(s):  
Selective Laser Melting ◽  
Laser Power ◽  
Scanning Speed ◽  
Experimental Investigations ◽  
Laser Melting ◽  
Scanning Strategy ◽  
Melt Pool ◽  
Corner Effects ◽  
Different Levels ◽  
Surface Changes

Experimental investigations on top surface of prismatic specimens, manufactured by Selective Laser Melting of IN 625 alloy, were carried out in order to assess the influence of laser power and scanning speed on edge and corner effects. Since the melt-pool behaviour is strongly influenced by the process parameters, all specimens were manufactured with no contour using the same layer thickness, hatch distance and scanning strategy at different levels of laser powers and scanning speeds. 3D laser surface scanning was performed in order to measure surface changes. The experimental results have revealed that melt-pool behaviour during solidification generates elevated ridges on both specimen sides and corners that are strongly influenced by the energy input. The edge ridges width increases with increasing the laser power and decrease with increasing the scanning speed, the rising of corners being much more pronounced. On the contrary, at constant laser power and variable scanning speeds the edge and corner ridges decrease.

In-situ capture of melt pool signature in selective laser melting using U-Net-based convolutional neural network

2021 ◽  
Vol 68 ◽  
pp. 347-355
Author(s):  
Qihang Fang ◽  
Zhenbiao Tan ◽  
Hui Li ◽  
Shengnan Shen ◽  
Sheng Liu ◽  
...  
Keyword(s):  
Neural Network ◽  
Convolutional Neural Network ◽  
Selective Laser Melting ◽  
Laser Melting ◽  
Melt Pool

scholarly journals Prediction of lack of fusion porosity in selective laser melting based on melt pool monitoring data

2019 ◽  
Vol 25 ◽  
pp. 347-356 ◽  
Author(s):  
Sam Coeck ◽  
Manisha Bisht ◽  
Jan Plas ◽  
Frederik Verbist
Keyword(s):  
Selective Laser Melting ◽  
Monitoring Data ◽  
Laser Melting ◽  
Lack Of Fusion ◽  
Melt Pool

scholarly journals Influence of the Manufacturing Parameters in Selective Laser Melting on Properties of Aluminum Alloy AlSi7Mg0.6 (A357)

2021 ◽  
Vol 45 (1) ◽  
pp. 1-10
Author(s):  
Arnold Mauduit ◽  
Hervé Gransac ◽  
Sébastien Pillot
Keyword(s):  
Aluminum Alloy ◽  
Theoretical Model ◽  
Selective Laser Melting ◽  
Chemical Elements ◽  
Laser Melting ◽  
Operating Modes ◽  
Melt Pool ◽  
Section Area ◽  
Maximum Temperatures ◽  
Conduction Mode

Various selective laser melting (SLM) configurations (8 in all) were tested on aluminum alloy AlSi7Mg0.6 by making single tracks on parallelepipeds specimens. We used an energy balance as a means of connecting the machine parameters (power, speed, etc.) of the 8 configurations to the morphology (geometry) of the single tracks. On this basis, we correlated the width, depth and especially the section area of the melt pool (single track) to the linear energy density. We were also able to assess the absorption coefficient of the aluminum alloy AlSi7Mg0.6 as a function of the temperature. The study was then focused on the microstructure and the possible impacts on the material properties including on the mechanical characteristics and the anisotropy observed in literature based on the build direction. Evidence suggests that the Hall-Petch relation can be used to explain this anisotropy. The thermal analysis highlighted two laser operating modes: the keyhole mode and the conduction mode. These modes have also been described via the morphology of the single tracks. Finally, a comparison between Rosenthal’s theoretical model (in the case of the conduction mode) and actual conditions was proposed by the obtained geometry of the single tracks as well as the cooling speeds calculated and measured using the dendrite arm spacing (DAS). The maximum temperatures achieved were also assessed by Rosenthal’s theoretical model which made it possible to explain the evaporation of some chemical elements during the manufacturing of the aluminum alloy through SLM.

scholarly journals Texture control of 316L parts by modulation of the melt pool morphology in selective laser melting

2019 ◽  
Vol 264 ◽  
pp. 21-31 ◽  
Author(s):  
Olivier Andreau ◽  
Imade Koutiri ◽  
Patrice Peyre ◽  
Jean-Daniel Penot ◽  
Nicolas Saintier ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
Laser Melting ◽  
Melt Pool
Sign in / Sign up

Export Citation Format

Share Document