scholarly journals Epitaxial Growth of Silicon on Silicon Wafers by Direct Laser Melting

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4728
Author(s):  
Marie Le Dantec ◽  
Mustafa Abdulstaar ◽  
Marc Leparoux ◽  
Patrik Hoffmann
Keyword(s):  
Additive Manufacturing ◽  
Epitaxial Growth ◽  
Silicon Powder ◽  
Process Conditions ◽  
Single Element ◽  
Thermal Gradients ◽  
Laser Melting ◽  
Direct Laser ◽  
Final Microstructure ◽  
High Purity Silicon

Additive manufacturing (AM) of brittle materials remains challenging, as they are prone to cracking due to the steep thermal gradients present during melting and cooling after laser exposition. Silicon is an ideal brittle material for study since most of the physical properties of single-element materials can be found in the literature and high-purity silicon powders are readily available. Direct laser melting (DLM) of silicon powder was performed to establish the conditions under which cracks occur and to understand how the solidification front impacts the final microstructure. Through careful control of process conditions, paying special attention to thermal gradients and the growth velocity, epitaxial pillars free of cracks could be grown to a length of several millimeters.

scholarly journals Selective Laser Melting of Crack-Free High Density M2 High Speed Steel Parts by Baseplate Preheating

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Karolien Kempen ◽  
Bey Vrancken ◽  
Sam Buls ◽  
Lore Thijs ◽  
Jan Van Humbeeck ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
High Speed ◽  
Crack Formation ◽  
High Speed Steel ◽  
Thermal Gradients ◽  
Laser Melting ◽  
Mechanical And Physical Properties ◽  
The World ◽  
M2 High Speed Steel

Cracks and delamination, resulting from residual stresses, are a barrier in the world of additive manufacturing and selective laser melting (SLM) that prohibits the use of many metals in this field. By preheating the baseplate, thermal gradients are lowered and stresses can be reduced. In this work, some initial tests were performed with M2 high speed steel (HSS). The influence of preheating on density and mechanical and physical properties is investigated. The paper shows many promising results for the production of SLM parts in materials that are very sensitive to crack formation and delamination. When using a preheating of 200 °C, crack-free M2 HSS parts were produced with a relative density of 99.8%.

Structure and Mechanical Properties of AlSi10Mg Fabricated by Selective Laser Melting Additive Manufacturing (SLM-AM)

2015 ◽  
Vol 1111 ◽  
pp. 62-66 ◽  
Author(s):  
Idan Rosenthal ◽  
Moshe Nahmany ◽  
Adin Stern ◽  
Nachum Frage
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Electron Beam Welding ◽  
Rapid Progression ◽  
Thermal Gradients ◽  
Layer By Layer ◽  
Laser Melting ◽  
Additive Process ◽  
Building Products ◽  
Metallurgical Investigation

Additive manufacturing (AM) of metals is a relatively novel fabrication approach with growing interests in many industries. The AM process is based on building products originating from 3-D computer models, through localized melting of powder in a layered structure. The present research focused on the metallurgical investigation of AM AlSi10Mg parts fabricated by SLM-AM. The macrostructure of the product is a collage of solidified track segments, which were remelted several times by the adjacent neighboring tracks. The microstructure consists of fine cellular dendrites, which reflect high thermal gradients and rapid progression of the scanning laser during the AM process. The building strategy is crucial for the successful layer by layer additive process and the properties of the components. It was established that AM products yield higher mechanical properties than that for the parts fabricated by casting. Feasibility of AM parts joining by Electron Beam Welding (EBW) method is discussed.

scholarly journals Microstructure and Crystallographic Texture of Laser Additive Manufactured Nickel-Based Superalloys with Different Scanning Strategies

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 591
Author(s):  
Xingbo Liu ◽  
Hui Xiao ◽  
Wenjia Xiao ◽  
Lijun Song
Keyword(s):  
Additive Manufacturing ◽  
Epitaxial Growth ◽  
Crystallographic Texture ◽  
Continuous Wave ◽  
Flow Direction ◽  
Fiber Texture ◽  
Laves Phase ◽  
Solidification Structure ◽  
Columnar Grains ◽  
Scanning Strategies

Control of solidification structure and crystallographic texture during metal additive manufacturing is a challenging work which attracts the increasing interest of researchers. In the present work, two kinds of scanning strategies (i.e., single-directional scanning (SDS) and cross-directional scanning (CDS) were used to control the solidification structure and crystallographic texture during quasi-continuous-wave laser additive manufacturing (QCW-LAM) of Inconel 718. The results show that the solidification structure and texture are strongly dependent on scanning strategies. The SDS develops a typical fiber texture with unidirectional columnar grains, whereas the CDS develops a more random texture with a mixture of unidirectional and multidirectional grains. In addition, the SDS promotes the continuously epitaxial growth of columnar dendrites and results in the linearly distributed Laves phase particles, while the CDS leads to the alternately distributed Laves phase particles with chain-like morphology and discrete morphology. The changed stacking features of molten-pool boundary and the switched heat flow direction caused by different scanning strategies plays a crucial role on the epitaxial growth of dendrites and the final solidification structure of the fabricated parts.

scholarly journals Improving surface quality in selective laser melting based tool making

2021 ◽  
Author(s):  
Filippo Simoni ◽  
Andrea Huxol ◽  
Franz-Josef Villmer
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Melting Process ◽  
Laser Remelting ◽  
Laser Melting ◽  
Great Cost ◽  
Starting Point ◽  
Processing Techniques

AbstractIn the last years, Additive Manufacturing, thanks to its capability of continuous improvements in performance and cost-efficiency, was able to partly replace and redefine well-established manufacturing processes. This research is based on the idea to achieve great cost and operational benefits especially in the field of tool making for injection molding by combining traditional and additive manufacturing in one process chain. Special attention is given to the surface quality in terms of surface roughness and its optimization directly in the Selective Laser Melting process. This article presents the possibility for a remelting process of the SLM parts as a way to optimize the surfaces of the produced parts. The influence of laser remelting on the surface roughness of the parts is analyzed while varying machine parameters like laser power and scan settings. Laser remelting with optimized parameter settings considerably improves the surface quality of SLM parts and is a great starting point for further post-processing techniques, which require a low initial value of surface roughness.

scholarly journals Directionally-Dependent Mechanical Properties of Ti6Al4V Manufactured by Electron Beam Melting (EBM) and Selective Laser Melting (SLM)

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3603
Author(s):  
Tim Pasang ◽  
Benny Tavlovich ◽  
Omry Yannay ◽  
Ben Jakson ◽  
Mike Fry ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Tensile Strength ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Electron Beam Melting ◽  
Rolling Direction ◽  
Laser Melting ◽  
Plate Rolling

An investigation of mechanical properties of Ti6Al4V produced by additive manufacturing (AM) in the as-printed condition have been conducted and compared with wrought alloys. The AM samples were built by Selective Laser Melting (SLM) and Electron Beam Melting (EBM) in 0°, 45° and 90°—relative to horizontal direction. Similarly, the wrought samples were also cut and tested in the same directions relative to the plate rolling direction. The microstructures of the samples were significantly different on all samples. α′ martensite was observed on the SLM, acicular α on EBM and combination of both on the wrought alloy. EBM samples had higher surface roughness (Ra) compared with both SLM and wrought alloy. SLM samples were comparatively harder than wrought alloy and EBM. Tensile strength of the wrought alloy was higher in all directions except for 45°, where SLM samples showed higher strength than both EBM and wrought alloy on that direction. The ductility of the wrought alloy was consistently higher than both SLM and EBM indicated by clear necking feature on the wrought alloy samples. Dimples were observed on all fracture surfaces.

scholarly journals Fabrication of Mesh Patterns Using a Selective Laser-Melting Process

2019 ◽  
Vol 9 (9) ◽  
pp. 1922 ◽  
Author(s):  
Tae Woo Hwang ◽  
Young Yun Woo ◽  
Sang Wook Han ◽  
Young Hoon Moon
Keyword(s):  
Selective Laser Melting ◽  
Laser Scanning ◽  
Dimensional Accuracy ◽  
Base Plate ◽  
Steel Powder ◽  
Melting Process ◽  
304 Stainless Steel ◽  
Process Conditions ◽  
Laser Melting ◽  
Metal Mesh

The selective laser-melting (SLM) process can be applied to the additive building of complex metal parts using melting metal powder with laser scanning. A metal mesh is a common type of metal screen consisting of parallel rows and intersecting columns. It is widely used in the agricultural, industrial, transportation, and machine protection sectors. This study investigated the fabrication of parts containing a mesh pattern from the SLM of AISI 304 stainless steel powder. The formation of a mesh pattern has a strong potential to increase the functionality and cost-effectiveness of the SLM process. To fabricate a single-layered thin mesh pattern, laser layering has been conducted on a copper base plate. The high thermal conductivity of copper allows heat to pass through it quickly, and prevents the adhesion of a thin laser-melted layer. The effects of the process conditions such as the laser scan speed and scanning path on the size and dimensional accuracy of the fabricated mesh patterns were characterized. As the analysis results indicate, a part with a mesh pattern was successfully obtained, and the application of the proposed method was shown to be feasible with a high degree of reliability.

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