Modeling the Selective Laser Melting of Multi-Component Thermoelectric Powders

2018 ◽  
Author(s):  
Yongjia Wu ◽  
Lei Zuo ◽  
Kan Sun
Keyword(s):  
Selective Laser Melting ◽  
High Performance ◽  
Low Cost ◽  
Electrical Energy ◽  
Device Fabrication ◽  
Thermoelectric Device ◽  
Laser Melting ◽  
Thermoelectric Modules ◽  
Powder Bed ◽  
Unique Method

Thermoelectrics enables thermal and electrical energy conversion or device cooling without any moving parts. It has remained a significant challenge to manufacture compact and high performance thermoelectric modules in a large volume using the conventional methods because of their drawbacks in practice, such as the long processing time and misalignment of individual thermoelectric elements. Selective laser melting (SLM) based additive manufacturing approach might offer a unique method to fabricate the low cost, reliable, highly efficient, scalable, and environmentally friendly thermoelectric modules. To understand the thermodynamic and hydrodynamic phenomenon during the SLM processing is of critical importance to ensure high quality products. In this paper, we developed a model which can be used to guide the SLM manufacturing of thermoelectric material with other nanoparticles embedded for higher thermoelectric performance. This physical model based on the continuous equations had the ability to analyze the fluid flow driven by buoyancy force and surface tension, which can be used to analyze the influence of the process parameters on the pool size, particle segregation, as well as temperature distribution within the powder bed. This information is very useful for developing robust SLM for thermoelectric device fabrication.

Selective laser melting of CP-Ti to overcome the low cost and high performance trade-off

2020 ◽  
Vol 34 ◽  
pp. 101198 ◽  
Author(s):  
Qiying Tao ◽  
Zhangwei Wang ◽  
Gang Chen ◽  
Wei Cai ◽  
Peng Cao ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
High Performance ◽  
Low Cost ◽  
Laser Melting ◽  
Trade Off ◽  
Cp Ti

scholarly journals A novel physics-based and data-supported microstructure model for part-scale simulation of laser powder bed fusion of Ti-6Al-4V

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jonas Nitzler ◽  
Christoph Meier ◽  
Kei W. Müller ◽  
Wolfgang A. Wall ◽  
N. E. Hodge
Keyword(s):  
Selective Laser Melting ◽  
Microstructure Evolution ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Laser Melting ◽  
Cooling Rates ◽  
Powder Bed ◽  
Proposed Model ◽  
Microstructure Model ◽  
Transformation Diagrams

AbstractThe elasto-plastic material behavior, material strength and failure modes of metals fabricated by additive manufacturing technologies are significantly determined by the underlying process-specific microstructure evolution. In this work a novel physics-based and data-supported phenomenological microstructure model for Ti-6Al-4V is proposed that is suitable for the part-scale simulation of laser powder bed fusion processes. The model predicts spatially homogenized phase fractions of the most relevant microstructural species, namely the stable $$\beta $$ β -phase, the stable $$\alpha _{\text {s}}$$ α s -phase as well as the metastable Martensite $$\alpha _{\text {m}}$$ α m -phase, in a physically consistent manner. In particular, the modeled microstructure evolution, in form of diffusion-based and non-diffusional transformations, is a pure consequence of energy and mobility competitions among the different species, without the need for heuristic transformation criteria as often applied in existing models. The mathematically consistent formulation of the evolution equations in rate form renders the model suitable for the practically relevant scenario of temperature- or time-dependent diffusion coefficients, arbitrary temperature profiles, and multiple coexisting phases. Due to its physically motivated foundation, the proposed model requires only a minimal number of free parameters, which are determined in an inverse identification process considering a broad experimental data basis in form of time-temperature transformation diagrams. Subsequently, the predictive ability of the model is demonstrated by means of continuous cooling transformation diagrams, showing that experimentally observed characteristics such as critical cooling rates emerge naturally from the proposed microstructure model, instead of being enforced as heuristic transformation criteria. Eventually, the proposed model is exploited to predict the microstructure evolution for a realistic selective laser melting application scenario and for the cooling/quenching process of a Ti-6Al-4V cube of practically relevant size. Numerical results confirm experimental observations that Martensite is the dominating microstructure species in regimes of high cooling rates, e.g., due to highly localized heat sources or in near-surface domains, while a proper manipulation of the temperature field, e.g., by preheating the base-plate in selective laser melting, can suppress the formation of this metastable phase.

A SIMULATION STUDY ON THE EFFECT OF PARTICLE SIZE DISTRIBUTION ON THE PRINTED GEOMETRY IN SELECTIVE LASER MELTING

2021 ◽  
pp. 1-14
Author(s):  
Vaishak Ramesh Sagar ◽  
Samuel Lorin ◽  
Johan Göhl ◽  
Johannes Quist ◽  
Christoffer Cromvik ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Layer Thickness ◽  
Selective Laser Melting ◽  
Laser Melting ◽  
Powder Bed ◽  
Mean Particle Size ◽  
Final Layer ◽  
Effect Of Particle Size

Abstract Selective laser melting (SLM) process is a powder bed fusion additive manufacturing process that finds applications in aerospace and medical industries for its ability to produce complex geometry parts. As the raw material used is in powder form, particle size distribution (PSD) is a significant characteristic that influences the build quality in turn affecting the functionality and aesthetics aspects of the product. This paper investigates the effect of PSD on the printed geometry for 316L stainless steel powder, where three coupled in-house simulation tools based on Discrete Element Method (DEM), Computational Fluid Dynamics (CFD), and Structural Mechanics are employed. DEM is used for simulating the powder bed distribution based on the different powder PSD. The CFD is used as a virtual testbed to determine thermal parameters such as heat capacity and thermal conductivity of the powder bed viewed as a continuum. The values found as a stochastic function of the powder distribution is used to analyse the effect on the melted zone and deformation using Structural Mechanics. Results showed that mean particle size and PSD had a significant effect on the packing density, melt pool layer thickness, and the final layer thickness after deformation. Specifically, a narrow particle size distribution with smaller mean particle size and standard deviation produced solidified final layer thickness closest to nominal layer thickness. The proposed simulation approach and the results will catalyze in development of geometry assurance strategies to minimize the effect of particle size distribution on the geometric quality of the printed part.

Alumina Reinforced EP648 Metal Matrix Composite Produced by Selective Laser Melting Powder Bed Fusion Additive Technology

2021 ◽  
Vol 316 ◽  
pp. 181-186
Author(s):  
P.A. Lykov ◽  
L. V. Radionova
Keyword(s):  
Selective Laser Melting ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Composite Powder ◽  
Additive Technology ◽  
Ceramic Powders ◽  
Laser Melting ◽  
Two Phase ◽  
Powder Bed ◽  
Scanning Electron

This paper is devoted to fabrication of alumina reinforced EP648 matrix composite material, using selective laser melting. of two-phase composite powder, prepared by ball milling of metal and ceramic powders. Five 10x10x5 mm bulk specimens were successfully manufactured using different process parameters. The obtained MMC specimens were characterized by scanning electron microscopy.

LaF3-BaF2-KF derived electrolyte in solid state fluoride-ion battery

2010 ◽  
Vol 1266 ◽  
Author(s):  
Dechao Wang ◽  
Anji Reddy Munnangi ◽  
Horst Hahn ◽  
Max Fichtner
Keyword(s):  
Solid State ◽  
High Performance ◽  
Low Cost ◽  
Electrical Energy ◽  
Composite Cathode ◽  
Fluoride Anion ◽  
Cubic Symmetry ◽  
Group A ◽  
Battery Technology ◽  
Preparation Techniques

AbstractSolid-state based battery technology offers, in principle, the largest temperature range (from room temperature to 500 °C) of any battery technology. In fluoride based batteries, the chemical reaction used to create electrical energy is a solid-state reaction of a metal with fluoride anion [1]. Among the various types of solid preparation techniques, the mechanochemical synthesis has been recognized as a powerful route to novel, high-performance, and low-cost materials [2]. Thus, a mixed and highly disordered fluoride phase with retained cubic symmetry can be obtained with a very high Fˉ diffusivity [3].In our group, a series of new electrolytes was developed, namely LaF3-BaF2-KF solid solutions, using mechanosynthesis method. The cubic structure of the product was confirmed by XRD. The nanoscale nature and morphology of the samples were characterized by SEM and TEM. First Solid-state electrochemical cells were built with LiF based composite cathode, LaF3-BaF2-KF derived electrolyte and Fe based composite anode.

scholarly journals An Overview of Additive Manufacturing Technologies—A Review to Technical Synthesis in Numerical Study of Selective Laser Melting

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3895 ◽  
Author(s):  
Abbas Razavykia ◽  
Eugenio Brusa ◽  
Cristiana Delprete ◽  
Reza Yavari
Keyword(s):  
Numerical Simulation ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Powder Bed Fusion ◽  
Laser Melting ◽  
Powder Bed ◽  
Part Quality ◽  
Melt Pool ◽  
Wide Range ◽  
Am Processes

Additive Manufacturing (AM) processes enable their deployment in broad applications from aerospace to art, design, and architecture. Part quality and performance are the main concerns during AM processes execution that the achievement of adequate characteristics can be guaranteed, considering a wide range of influencing factors, such as process parameters, material, environment, measurement, and operators training. Investigating the effects of not only the influential AM processes variables but also their interactions and coupled impacts are essential to process optimization which requires huge efforts to be made. Therefore, numerical simulation can be an effective tool that facilities the evaluation of the AM processes principles. Selective Laser Melting (SLM) is a widespread Powder Bed Fusion (PBF) AM process that due to its superior advantages, such as capability to print complex and highly customized components, which leads to an increasing attention paid by industries and academia. Temperature distribution and melt pool dynamics have paramount importance to be well simulated and correlated by part quality in terms of surface finish, induced residual stress and microstructure evolution during SLM. Summarizing numerical simulations of SLM in this survey is pointed out as one important research perspective as well as exploring the contribution of adopted approaches and practices. This review survey has been organized to give an overview of AM processes such as extrusion, photopolymerization, material jetting, laminated object manufacturing, and powder bed fusion. And in particular is targeted to discuss the conducted numerical simulation of SLM to illustrate a uniform picture of existing nonproprietary approaches to predict the heat transfer, melt pool behavior, microstructure and residual stresses analysis.

Modeling, Simulation and Experimental Validation of Heat Transfer During Selective Laser Melting

2015 ◽  
Author(s):  
Mohammad Masoomi ◽  
Xiang Gao ◽  
Scott M. Thompson ◽  
Nima Shamsaei ◽  
Linkan Bian ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mechanical Properties ◽  
Selective Laser Melting ◽  
Heat Fluxes ◽  
Transient Temperature ◽  
Thermal Gradients ◽  
Layer By Layer ◽  
Metal Powders ◽  
Laser Melting ◽  
Powder Bed

Selective Laser Melting (SLM), a laser powder-bed fusion (PBF-L) additive manufacturing method, utilizes a laser to selectively fuse adjacent metal powders. The powders are aligned in a bed that moves vertically to allow for layer-by-layer part construction-Process-related heat transfer and thermal gradients have a strong influence on the microstructural features, and subsequent mechanical properties, of the parts fabricated via SLM. In order to understand and control the heat transfer inherent to SLM, and to ensure high quality parts with targeted microstructures and mechanical properties, comprehensive knowledge of the related energy and mass transport during manufacturing is required. In this study, the transient temperature distribution within and around parts being fabricated via SLM is numerically simulated and the results are provided to aid in quantify the SLM heat transfer. In order to verify simulation output, and to estimate actual thermal gradients and heat transfer, experiments were separately conducted within a SLM machine using a substrate with embedded thermocouples. The experiments focused on characterizing heat fluxes during initial deposition on an initially-cold substrate and during the fabrication of a thin-walled structure built via stainless steel 17-4 powders. Results indicate that it is important to model heat transfer thorough powder bed as well as substrate.

Review on Powder-Bed Laser Additive Manufacturing of Inconel 718 Parts

2015 ◽  
Author(s):  
Xiaoqing Wang ◽  
Xibing Gong ◽  
Kevin Chou
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Literature Review ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Manufacturing Processes ◽  
Laser Melting ◽  
Laser Additive Manufacturing ◽  
Powder Bed ◽  
General Aspects

This study presents a thorough literature review on the powder-bed laser additive manufacturing processes such as selective laser melting (SLM) of Inconel 718 parts. The paper first introduces the general aspects of powder-bed laser additive manufacturing and then discusses the unique characteristics and advantages of SLM. Moreover, the bulk of this study includes extensive discussions of microstructures and mechanical properties, together with the application ranges, of Inconel 718 parts fabricated by SLM.

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.

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