Sintering of commercially pure titanium powder with a Nd:YAG laser source

Fischer, Pascal; Romano, Valerio; Weber, H. P.; Karapatis, N. P.; Boillat, Éric; Glardon, Rémy

doi:10.1016/s1359-6454(02)00567-0

Cited by 327 publications

(179 citation statements)

References 6 publications

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“…Caution is expressed when choosing because these values vary widely between experimental studies for both powder and solid medium [19]. For powder, this is assumed to be the same as pure titanium powder [34] and for the solid substrate is assumed to be [35]. Normally, to account for latent heat, the specific heat is modified in a finite interval between the solidus and liquidus temperatures.…”

Section: Laser Heat Inputmentioning

confidence: 99%

Understanding the effect of laser scan strategy on residual stress in selective laser melting through thermo-mechanical simulation

Parry

Ashcroft

Wildman

2016

Additive Manufacturing

421

287

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. Abstract: Selective laser melting (SLM) is an attractive technology, enabling the manufacture of customised, complex metallic designs, with minimal wastage. However, uptake by industry is currently impeded by several technical barriers, such as the control of residual stress, which have a detrimental effect on the manufacturability and integrity of a component. Indirectly, these impose severe design restrictions and reduce the reliability of components, driving up costs. This paper uses a thermo-mechanical model to better understand the effect of laser scan strategy on the generation of residual stress in SLM. A complex interaction between transient thermal history and the build-up of residual stress has been observed in the two laser scan strategies investigated. The temperature gradient mechanism was discovered for the creation of residual stress. The greatest stress component was found to develop parallel to the scan vectors, creating an anisotropic stress distribution in the part. The stress distribution varied between laser scan strategies and the cause has been determined by observing the thermal history during scanning. Using this, proposals are suggested for designing laser scan strategies used in SLM. Abstract:Selective laser melting (SLM) is an attractive technology, enabling the manufacture of customised, complex metallic designs, with minimal wastage. However, uptake by industry is currently impeded by several technical barriers, such as the control of residual stress, which have a detrimental effect on the manufacturability and integrity of a component. Indirectly, these impose severe design restrictions and reduce the reliability of components, driving up costs. This paper uses a thermomechanical model to better understand the effect of laser scan strategy on the generation of residual stress in SLM. A complex interaction between transient thermal history and the build-up of residual stress has been observed in the two laser scan strategies investigated. The temperature gradient mechanism was discovered for the creation of residual stress. The greatest stress component was found to develop parallel to the scan vectors, creating an anisotropic stress distribution in the part. The stress distribution varied between laser scan strategies and the cause has been determined by observing the thermal history during scanning. Using this, proposals are suggested for designing laser scan strategies used in SLM. Nomenclature:Specific

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Section: Laser Heat Inputmentioning

confidence: 99%

Understanding the effect of laser scan strategy on residual stress in selective laser melting through thermo-mechanical simulation

Parry

Ashcroft

Wildman

2016

Additive Manufacturing

421

287

View full text Add to dashboard Cite

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“…The physical behaviour of the SLM process includes absorption, reflection, radiation, and heat transfer, melting and coalescence of powder particles, phase transformations, a moving interface between solid phase and liquid phase, fluid flow caused by the surface tension gradient and mass transportation within the molten pool followed by solidification, and chemical reactions [26,35]. Because of the use of high-intensity laser, the powder particles are heated at a faster rate as the energy is absorbed via both bulk-coupling and powder-coupling mechanisms [36]. The energy is converted into heat and eventually the powder particles melt, coalesce, and form an agitated melt pool for some milliseconds (typically 0.5 to 25 ms).…”

Section: Selective Laser Melting (Slm) Technologymentioning

confidence: 99%

Selective Laser Melting of Magnesium and Magnesium Alloy Powders: A Review

Manakari

Parande

Gupta

2016

Metals

190

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Magnesium-based materials are used primarily in developing lightweight structures owing to their lower density. Further, being biocompatible they offer potential for use as bioresorbable materials for degradable bone replacement implants. The design and manufacture of complex shaped components made of magnesium with good quality are in high demand in the automotive, aerospace, and biomedical areas. Selective laser melting (SLM) is becoming a powerful additive manufacturing technology, enabling the manufacture of customized, complex metallic designs. This article reviews the recent progress in the SLM of magnesium based materials. Effects of SLM process parameters and powder properties on the processing and densification of the magnesium alloys are discussed in detail. The microstructure and metallurgical defects encountered in the SLM processed parts are described. Applications of SLM for potential biomedical applications in magnesium alloys are also addressed. Finally, the paper summarizes the findings from this review together with some proposed future challenges for advancing the knowledge in the SLM processing of magnesium alloy powders.

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“…Meander and stripes laser scanning have smoother surfaces, the roughness changes from 12 to 6 µm with the variation of the building angle. Some authors [13,44] have reported that roughness values Ra vary depending on the parameters used during the melting process. For this work, the authors show that chessboard laser scanning creates rougher surfaces, the scanning shape changes continuously in orientation, and the areas to be consolidated are smaller than when using a one-dimensional scan.…”

Section: Roughnessmentioning

confidence: 99%

“…This effect is present to a greater or lesser degree in all additive layer-manufacturing processes as consequence of the manufacturing process and the layer discretization. Surface quality (surface roughness, corrosion, and porosity properties) is also influenced by process parameters such as temperature profiles and densification ratios, among others [13][14][15][16]. However, the layer thickness can be reduced in order to improve the surface finish [17], but a smooth surface is also constrained by the balling phenomenon, which refers to the particles either not melting at all or joining into rather large droplets, which occurs during laser melting [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Permeability Study of Austenitic Stainless Steel Surfaces Produced by Selective Laser Melting

Segura-Cárdenas

Ramírez-Cedillo

Sandoval-Robles

et al. 2017

Metals

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Selective laser melting (SLM) is emerging as a versatile process for fabricating different metal components with acceptable mechanical properties and geometrical accuracy. The process has been used in the manufacturing of several parts (e.g., aerospace or biomedical components), and offers the capability to tailor the performance of several surface and mechanical properties. In this work, permeability properties and surface roughness of stainless steel (SS316L) surfaces were evaluated through experimentation with three different laser scanning patterns (chessboard, meander, and stripe), and different sloping angles between the fabricated surface and the laser beam incident on the process. Results showed that for each scanning pattern, the roughness decreased as the sloping angle increased consistently in all experimental trials. Furthermore, in the case of the permeability evaluation, the manufactured surfaces showed changes in properties for each series of experiments performed with different scanning patterns. The chessboard pattern showed a change of 67 • to 107 • in contact angle, while the meander and stripe patterns showed a variation in contact angle in a range of 65 • to 85 • . The different scanning strategies in the SLM process resulted in an alternative method for surface enhancement with different hydrophobicity properties, valuable for designing the most appropriate permeability characteristics for specific applications.

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Sintering of commercially pure titanium powder with a Nd:YAG laser source

Cited by 327 publications

References 6 publications

Understanding the effect of laser scan strategy on residual stress in selective laser melting through thermo-mechanical simulation

Understanding the effect of laser scan strategy on residual stress in selective laser melting through thermo-mechanical simulation

Selective Laser Melting of Magnesium and Magnesium Alloy Powders: A Review

Permeability Study of Austenitic Stainless Steel Surfaces Produced by Selective Laser Melting

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