Epitaxial laser metal forming: analysis of microstructure formation

Gäumann, M.; Henry, S.; Cléton, F.; Wagnière, J.-D.; Kurz, W.

doi:10.1016/s0921-5093(99)00202-6

Cited by 437 publications

(205 citation statements)

References 12 publications

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“…1a Figure 3a shows a typical columnar microstructure which is obtained after additive manufacturing with SEBM with a standard cross snake scanning strategy and slow beam parameters. The columnar microstructure with a strong texture in building direction results from epitaxial growth and steep temperature gradients mostly parallel to the building direction [2][3][4]16]. With the same area energy but lower line offset and higher deflection speed the grain structure becomes equiaxed, see Fig.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Tailoring the grain structure of IN718 during selective electron beam melting

Körner

Helmer

Bauereiß

et al. 2014

MATEC Web of Conferences

115

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Abstract. Selective electron beam melting (SEBM) is an additive manufacturing method where complex parts are built from metal powders in layers of about 50 µm. SEBM works under vacuum conditions which results in a perfect protection of the metal alloy. The electron beam is used for heating (about 900 • C building temperature) and selective melting. The high beam velocities allow innovative scanning strategies in order to adapt the local solidification conditions which determine the epitaxial solidification process of IN718. We show how scanning strategies can be used either to produce a columnar grain structure with a high texture in building direction or a complete texture-free fine grained structure. Numerical simulations of the selective melting process are applied to reveal the fundamental mechanisms responsible for the completely different grain structures. In addition the influence of the different grain structures on the mechanical properties of IN718 is briefly discussed.

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Section: Numerical Simulationsmentioning

confidence: 99%

Tailoring the grain structure of IN718 during selective electron beam melting

Körner

Helmer

Bauereiß

et al. 2014

MATEC Web of Conferences

115

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“…The growth of the dendrites is opposite to the resultant heat flow direction (Ref 3,19,20). In the DED process, heat of the melt flows mostly through the substrate or previously deposited layers; however, it can also be partially extracted through the adjacent solidified deposit layer which grew from the trailing end of the melt pool, and/or via the surrounding atmosphere.…”

Section: Effect Of Heat Release On Solidification Structurementioning

confidence: 99%

Additive Manufacturing of AlSi10Mg Alloy Using Direct Energy Deposition: Microstructure and Hardness Characterization

et al. 2016

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This paper aims to study the manufacturing of the AlSi10Mg alloy with direct energy deposition (DED) process. Following fabrication, the macro-and microstructural evolution of the as-processed specimens was initially investigated using optical microscopy and scanning electron microscopy. Columnar dendritic structure was the dominant solidification feature of the deposit; nevertheless, detailed microstructural analysis revealed cellular morphology near the substrate and equiaxed dendrites at the top end of the deposit. Moreover, the microstructural morphology in the melt pool boundary of the deposit differed from the one in the core of the layers. The remaining porosity of the deposit was evaluated by Archimedes' principle and by image analysis of the polished surface. Crystallographic texture in the deposit was also assessed using electron backscatter diffraction and x-ray diffraction analysis. The dendrites were unidirectionally oriented at an angle of *80°to the substrate. EPMA line scans were performed to evaluate the compositional variation and elemental segregation in different locations. Eventually, microhardness (HV) tests were conducted in order to study the hardness gradient in the as-DED-processed specimen along the deposition direction. The presented results, which exhibited a deposit with an almost defect free structure, indicate that the DED process can suitable for the deposition of Al-Si-based alloys with a highly consolidated structure.

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“…Metal powder, sprayed from powder delivery nozzle and injected into the laser focal zone, is heated to its melting temperature and melted completely. Then the liquid metal solidifies onto the prior deposited layers in the wake of the moving molten pool created by the laser beam, thus forming a layer of metal whose dimension is controlled by laser processing parameters [1][2][3]. Simultaneously, the substrate is moved in the horizontal plane beneath the laser beam to deposit a thin cross-section, thereby creating the desired geometry for each layer.…”

Section: Introductionmentioning

confidence: 99%

Study on Scanning Pattern during Laser Metal Deposition Shaping

Zhang

Shang

Liu

2009

2009 Second International Conference on Intelligent Computation Technology and Automation

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Abstract-The fabrication of metal parts is the backbone of the modern manufacturing industry. Laser forming is the combination of five common technologies: lasers, rapid prototyping (RP), computer-aided design (CAD), computeraided manufacturing (CAM), and powder metallurgy. The resulting process creates part by focusing an industrial laser beam on the surface of processing workpiece to create a molten pool of metal. A small stream of powdered alloy is then injected into the molten pool to build up the part gradually. By moving the laser beam back and forth and tracing out a pattern determined by a CAD, the solid metal part is fabricated line by line, one layer at a time. In the present work, a type of direct laser deposition process, called Laser Metal Deposition Shaping (LMDS), has been employed and developed to fabricate metal parts. Through the comprehensive experiments, it is found that this process is affected by many factors. Besides the processing parameters, scanning pattern is the one that strongly influences the quality and precision of as-fabricated parts. In comparison with the forming effects of different scanning patterns, the most suitable one can be selected to carry out this laser forming process. Finally, with the suitable scanning patterns, the high performance of the formed alloys is confirmed after the above studies.

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Epitaxial laser metal forming: analysis of microstructure formation

Cited by 437 publications

References 12 publications

Tailoring the grain structure of IN718 during selective electron beam melting

Tailoring the grain structure of IN718 during selective electron beam melting

Additive Manufacturing of AlSi10Mg Alloy Using Direct Energy Deposition: Microstructure and Hardness Characterization

Study on Scanning Pattern during Laser Metal Deposition Shaping

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