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See detailEffect of solution treatment on the fracture mechanisms of AlSi10Mg parts produced by Selective Laser Melting
Delahaye, Jocelyn ULiege; Mertens, Anne ULiege; Dedry, Olivier ULiege et al

Poster (2017, September 21)

Al alloy AlSi10Mg processed by Selective Laser Melting (SLM) displays high hardness and tensile strength due to its very fine eutectic microstructure [1]. However, as-built material exhibits low ductility ... [more ▼]

Al alloy AlSi10Mg processed by Selective Laser Melting (SLM) displays high hardness and tensile strength due to its very fine eutectic microstructure [1]. However, as-built material exhibits low ductility which is detrimental for applications where a high resilience is needed. To overcome this issue, solution heat treatment can be applied to soften and ductilize the material [2]. The very fine eutectic microstructure then turns into a dispersion of coarse globular Si precipitates. The distribution of Si precipitates seems to play a role in the fracture mechanism in as-built as well as solutionized tempers, but this effect is not yet fully understood [1,3]. Moreover, the lack of quantitative data makes it difficult to link precisely the fracture mechanisms to specific microstructural features. This study aims at investigating the role of the Si phase in the rupture mechanism, for both as-built and solutionized samples. It will focus more particularly on the heterogeneity of the distribution of Si precipitates where cracks are more likely to occur. Al cells size, along with the volume fraction and distribution of Si precipitates have been quantified by SEM image analysis. Al lattice parameter and Si crystallite size have been determined by X-ray diffraction/Rietveld analysis. For the image analysis, two types of specific zones have been observed i.e. the core and boundary of melt pools and Al grains, at different locations for representativity. These quantitative data have been compared with typical features observed on the fractured surface of tensile specimen. 1. D.-K. Kim et al. J. Alloys Compd. 686 (2016) 281. 2. W. Li et al., Mat. Sci. & Eng. A. 663 (2016) 116, 3. N.T. Aboulkhair et al. Mat. Sci. & Eng. A. 667 (2016) 139. [less ▲]

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See detailValidation of a TEOS based sol-gel coating for the protection of carbon fibres against oxidation regarding their use in metal matrix composites
Montrieux, Henri-Michel ULiege; Lecomte-Beckers, Jacqueline ULiege; Halleux, Jacques et al

Poster (2017, September 07)

The use of sol-gel coating on graphite substrates has sucessfuly been done. In particular, in the field of metal matrix composites, some authors state that the use and cure of TEOS sol-gel on carbon based ... [more ▼]

The use of sol-gel coating on graphite substrates has sucessfuly been done. In particular, in the field of metal matrix composites, some authors state that the use and cure of TEOS sol-gel on carbon based fibres may improve the liquid magnesium infiltration. The described mechanism is the lowering of the liquid/solid contact angle under some specific conditions of time and temperature by the occurrence of a metal-oxide exothermal chemical reaction. Furthermore the application of silica based sol-gels on carbon fibres in order to control the medium to high temperature oxidation of fibres preforms is less investigated. The primary objective is to understand more deeply the oxidation of some uncoated fibres by the comparison of ESEM observations to TGA/ATD curves. The secondary objective is to formulate and coat a TEOS based sol-gel on T300 carbon fibres and to evaluate the new oxidation behaviour. The ternary objective is to measure in a simple way the gain of oxidation resistance of some coated fibres. [less ▲]

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See detailFusion-based Additive Manufacturing for Processing Aluminum Alloys: State-of-the-Art and Challenges
Mertens, Anne ULiege; Delahaye, Jocelyn ULiege; Lecomte-Beckers, Jacqueline ULiege et al

in Advanced Engineering Materials (2017), 19(8), 1700003

Starting early 2015, the fusion-based additive manufacturing of Al alloys has been developing at an ever faster pace after undergoing a comparatively slow start with respect to other metallic materials ... [more ▼]

Starting early 2015, the fusion-based additive manufacturing of Al alloys has been developing at an ever faster pace after undergoing a comparatively slow start with respect to other metallic materials. This paper reviews the recent developments with the aim of identifying major challenges and opportunities for future work. Laser Beam Melting proves the most useful technique for the additive fabrication of Al components with strongly out-of-equilibrium microstructures and potentially enhanced mechanical behavior. Laser Cladding is also promising for specific applications such as repairs and coatings. However, a deeper understanding of the thermal history during fabrication is still needed to further optimize the microstructures and usage properties. The design of new high strength alloys and of Al-matrix composites, and the development of better adapted post-processing procedures to take greater advantage of the specificities of fusion-based additive techniques are two other important issues in view of reaching the full potential of additive Al components. [less ▲]

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See detail3D thermal finite element analysis of laser cladding processed Ti-6Al-4V part with microstructural correlations
Tran, Hoang Son ULiege; Tchuindjang, Jérôme Tchoufack ULiege; Paydas, Hakan ULiege et al

in Materials & Design (2017), 128

In this study, a 3D thermal model of laser cladding by powder injection applied to Ti-6Al-4V is developed. The manufactured part is made of a Ti-6Al-4V substrate on which successive layers of laser melted ... [more ▼]

In this study, a 3D thermal model of laser cladding by powder injection applied to Ti-6Al-4V is developed. The manufactured part is made of a Ti-6Al-4V substrate on which successive layers of laser melted powder are added, leading to a thick deposit. The computed temperature field and its time evolution are compared to experimental measurements. The temperature distribution in the substrate allows the prediction of the depths of the melt pool and the heat affected zone. Correlations between simulated thermal histories and the final microstructure in the thick deposit are established, leading to the enhancement of a dynamic shift of the critical transformation points due to high thermal rates during laser processing. The nature of the phases present within the deposit is discussed. [less ▲]

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See detailEffects of High Solidification Rates on Segregations and Solid Phase Transformations in High Speed Steels
Tchuindjang, Jérôme Tchoufack ULiege; Sinnaeve, Mario; Lecomte-Beckers, Jacqueline ULiege

in MATSUBARA, Yasuhiro; SASAGURI, Nobuya; YAMAMOTO, Kaoru (Eds.) ABRASION 2017 - The 6th International COnference on Abrasion Wear Resistant Alloyed White Cast Iron for Rolling and Pulverizing Mills (2017, August)

High Speed Steels (HSS) represent high alloyed steels that belong to the complex Fe-Cr-C-X system whit X being a strong carbide forming element such as V, Nb, Mo or W. During the solidification of HSS ... [more ▼]

High Speed Steels (HSS) represent high alloyed steels that belong to the complex Fe-Cr-C-X system whit X being a strong carbide forming element such as V, Nb, Mo or W. During the solidification of HSS, segregations corresponding to preferential distribution of elements can occur. Segregations are influenced both by the initial chemical composition and by the casting route, which is the case with conventional spin casting process. But the same phenomenon should also exist with the expanding additive manufacturing techniques that involved higher thermal gradients and higher cooling rates compared to classical processes. The solid phase transformations are controlled by the local concentrations of elements, especially the supersaturation which may exist in certain regions. That is the reason why the segregations inherited from the solidification of the HSS alloys lead to unexpected solid state phase transformations during the ongoing cooling stage. These phase transformations may occur either in the moderate temperature range or subsequently in the lower temperature range which is close to the ambient temperature, as for the martensitic transformation. In the present work a general review of the literature dealing with the fundamentals of solidification is reviewed aiming at justifying the need to search for tools that will be more adapted to simulate or study the microstructures obtained by manufacturing processes such as laser cladding, which refer to conditions far away from equilibrium. The new approach to understanding non-equilibrium structures also requires consideration of related studies with materials that are different from the HSS alloys, such as stainless steels, in order to take advantage of relevant analyzes that have already been achieved in other areas. The study is open, because the scope of the analyses is large and it can be extend to the phase transformations and also to the properties. Some relevant results obtained on two HSS processed by laser cladding are discussed related to the solidification mode and the solidification sequence. [less ▲]

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See detailThermal treatments for tailoring the microstructure and wear behaviour of friction stir processed Aluminium-C fibres composites
Mertens, Anne ULiege; Storti, Marco; Simar, Aude et al

Conference (2017, July 10)

A new and simple method for the production of metal matrix composite by friction stir processing (FSP) sandwiches made from metal sheets (e.g. Mg- or Al-based alloy) intercalated with a reinforcing ... [more ▼]

A new and simple method for the production of metal matrix composite by friction stir processing (FSP) sandwiches made from metal sheets (e.g. Mg- or Al-based alloy) intercalated with a reinforcing material e.g. a carbon fabric has recently been devised by the present authors [A. Mertens et al., Mater. Charact. 107 (2015), 125-133]. This process allowed the production of large-size sound metal matrix composites, but the usage properties (e.g. wear resistance,...) of these composites are not yet optimised. Indeed, the matrix of the composite may be softened after processing as FSP is known to cause dissolution of the precipitates responsible for strengthening Mg- or Al-based alloys [A. Simar et al., Mater. Sci. Eng. A 486 (2008), 85-95]. This work thus aims at investigating the potential of thermal treatments for tailoring the microstructure and wear behaviour of age hardenable aluminium alloy 6005 – C fibres composites. The effect of (solution and) ageing treatments on the microstructure and hardness of FSPed Al-C composites has been investigated using optical and scanning electron microscopy, along with Vickers hardness tests. The wear behaviour of the as-FSPed and of the heat treated specimens has been characterized using a pin-on-disc tribometer. Moreover, reference AA6005 samples without C fibres have been produced and tested under similar conditions. The comparison of the reference and of the composite samples allows a better understanding of the role of the C fibres in controlling the grain size of the Al matrix by influencing recrystallisation during FSP and grain growth during thermal treatments. [less ▲]

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See detailFunctional refractory molds for metal casting built by additive manufacturing
Bister, Geoffroy; Hautcoeur, Dominique; Deschuyteneer, Dorian et al

Conference (2017, July)

Additive manufacturing is more and more used in the field of industry. This technique is notably employed in investment casting process in order to build cores and models. Nevertheless investment casting ... [more ▼]

Additive manufacturing is more and more used in the field of industry. This technique is notably employed in investment casting process in order to build cores and models. Nevertheless investment casting remains not cost effective in case of prototypes and very small series due to the quite large amount time needed to build and dry the molds. Additive manufacturing may also be used to directly shape metal parts but several problems are still linked to this technique as the presence of local defects in parts and the limitation of the number of metal or alloy available for this technique on the market. We propose an intermediate method that permits to build directly molds and cores by additive manufacturing using equipment initially dedicated to build metal parts. This method presents the main advantage to cast with a large variety of metals or alloys using a single ceramic material and only one set of building conditions. The properties of the casted parts are very similar with those produced by investment casting. This technique also permits the unique advantage to control the design of the shell thickness and structure in order to have a better control of the thermal fluxes during metal cooling. This would potentially ensure a better control of some casting defects. The use of alumina processed by selective laser melting (SLM) is shown and its outstanding resistance to temperature differential is demonstrated through casting trials with two diffferent representative alloys. Casting trials in industrial conditions will be illustrated. [less ▲]

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See detailInfluence of Si precipitates on fracture mechanisms of AlSi10Mg parts processed by Selective Laser Melting
Delahaye, Jocelyn ULiege; Rigo, Olivier; Lecomte-Beckers, Jacqueline ULiege et al

Conference (2017, June 28)

Al alloy AlSi10Mg processed by Selective Laser Melting displays a very fine cellular eutetic microstructure (melt pool fine, MP fine) due to fast cooling rate from the melt. Such microstructural ... [more ▼]

Al alloy AlSi10Mg processed by Selective Laser Melting displays a very fine cellular eutetic microstructure (melt pool fine, MP fine) due to fast cooling rate from the melt. Such microstructural refinement results in high tensile strength and hardness. Studies have shown that a coarser cells region (melt pool coarse, MP coarse) as well as a heat affected zone (HAZ) can be observed at the melt pool boundary caused by a change of thermal history [1]. Those microstructural inhomogeneities act like a weak zone as demonstrated by the laser tracks observed on fracture features after tensile test [2]. This study aims at investigating in which zone fracture occurs. To do so, MP fine, MP coarse and HAZ were analyzed. Si precipitates spacing was compared with dimples size observed on fracture features. The Si precipitates fraction were quantified by image analysis. Hardness tests were performed in the 3 different zones by nanoindentation. [1] Thijs et al., Acta Mater. 61 (2013) pp. 1809-1819 [2] Tang et al., JOM 69 (2017) pp. 516-522 [less ▲]

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See detailThermal history modelling to understand microstructures observed in repair technology of Ti-6Al-4V
Tomé Jardin, Ruben Antonio ULiege; Tchuindjang, Jérôme Tchoufack ULiege; Paydas, Hakan ULiege et al

Conference (2017, June 28)

Study of laser cladding as a possible technology to repair Ti-6Al-4V. Development of a FEM thermal to predict microstructure.

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See detailWear behaviour of laser clad High Speed Steels thick deposits
Hashemi, Seyedeh Neda ULiege; Tchuindjang, Jérôme Tchoufack ULiege; Dedry, Olivier ULiege et al

Conference (2017, June 28)

The wear behaviour of 4 different High Speed Steel (HSS) thick coatings (one cast material and 3 laser clad deposits with varying Mo, V and W contents) was investigated at 2 different test temperatures, i ... [more ▼]

The wear behaviour of 4 different High Speed Steel (HSS) thick coatings (one cast material and 3 laser clad deposits with varying Mo, V and W contents) was investigated at 2 different test temperatures, i.e. at room temperature and at 300°C. For all four materials under both test conditions, oxidative wear was identified as the main wear mechanism. The 3 laser clad deposits exhibit a higher wear resistance compared to the conventional cast reference material, and this effect was mainly attributed to their strongly refined microstructures. Moreover, a detailed comparison of the wear behaviour of the 3 laser clad deposits, in correlation with their microstructures, allows a better understanding of the effect of the different carbides and of their morphology. [less ▲]

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See detailFE modeling of the cooling and tempering steps of bimetallic rolling mill rolls
Neira Torres, Ingrid; Gilles, Gaëtan ULiege; Tchuindjang, Jérôme Tchoufack ULiege et al

in International Journal of Material Forming (2017), Volume 10,(Issue 3), 287305

Numerical simulations enable the analysis of the stress and strain histories of bimetallic rolling mill rolls. The history of rolling mill rolls is simulated by thermo-mechanical metallurgical finite ... [more ▼]

Numerical simulations enable the analysis of the stress and strain histories of bimetallic rolling mill rolls. The history of rolling mill rolls is simulated by thermo-mechanical metallurgical finite element code while considering two steps: post-casting cooling and subsequent tempering heat treatment. The model requires a notably large set of material parameters. For different phases and temperatures, Young modulus, yield limit and tangent plastic modulus are determined through compression tests. Rupture stresses and strains are obtained by tensile tests. Thermo-physical parameters are measured by such experimental methods as dilatometry, DSC (Differential Scanning Calorimetry) and Laser Flash methods. Such parameters as the transformation plasticity coefiicients for the ferrite, pearlite and martensite phases are identified through an inverse method. From the simulation results, the profile of the stresses evolution at different critical times is presented. An analysis of the potential damage is proposed by comparing the predicted axial stress \vith rupture stresses. The perspective of the Ghosh and McClintock damage criteria is also investigated. [less ▲]

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See detailOxidative wear behaviour of laser clad high speed steel thick deposits: influence of sliding speed, carbide type and morphology
Hashemi, Seyedeh Neda ULiege; Mertens, Anne ULiege; Montrieux, Henri-Michel ULiege et al

in Surface & Coatings Technology (2017), 315

The oxidative wear behaviour of four different High Speed Steel (HSS) thick coatings (one cast material and three laser clad deposits with varying Mo, V and W contents) was investigated using a pin-on ... [more ▼]

The oxidative wear behaviour of four different High Speed Steel (HSS) thick coatings (one cast material and three laser clad deposits with varying Mo, V and W contents) was investigated using a pin-on-disc tribometer at two different sliding speeds of 10cm/s and 50cm/s. Microstructural characterisation (before and after the wear tests) was carried out by SEM and wear debris was analysed by XRD. For all four materials, the oxide layer was formed of hard and brittle haematite-type α-Fe2O3, prone to break and release debris that acted as a third body, thus increasing sample wear. The laser clad HSS materials exhibited a higher wear resistance than their conventional cast counterpart, thanks to their finer microstructures. In particular, the coarser MC and M2C carbides present in the cast material were sensitive to cracking during the wear tests, releasing debris that contributed to increased third body abrasion together with oxide fragments. A detailed comparison of the wear behaviour of the three laser clad deposits, in correlation with their different microstructures, further demonstrated that harder V-rich MC carbides offered better wear resistance compared to the softer W-rich M2C carbides. The morphology of the carbides also played a role in determining the wear resistance at the higher sliding speed of 50 cm/s. Clover-shaped primary MC carbides resisted wear better than angular ones due to their better geometric anchoring. Similarly, the geometric anchoring of eutectic M2C carbides, forming a quasi-continuous network at the grain boundaries of the matrix, proved beneficial at higher sliding speed. [less ▲]

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See detailMicro-mechanical testing of magnesium based composites reinforced by carbon fibers manufactured by friction stir processing
Simar, Aude; Ryelandt, Sophie; Delannay, Francis et al

Conference (2017, February 28)

Short C fibres–Mg matrix (AZ91D) composites have been produced by friction stir processing sandwiches made of a layer of C fabric stacked between two sheets of Mg alloy. The process parameters have been ... [more ▼]

Short C fibres–Mg matrix (AZ91D) composites have been produced by friction stir processing sandwiches made of a layer of C fabric stacked between two sheets of Mg alloy. The process parameters have been optimized to ensure a good fiber distribution. 3D X-ray tomography reveals that the fibers orient like onion rings. Thermal treatments have allowed to modify the flow stress level of the matrix material. Tensile testing inside the scanning electron microscope have revealed the decohesion at the fiber/matrix interface if the fibers are preferentially oriented perpendicularly to the loading direction. Modelling allows to estimate the stress needed to initiate this decohesion is about 250 MPa, i.e. appearing early in heat treated samples. To compare with different loading conditions, micro-compression and instrumented micro-indentation testing have also been performed. The consequence of the loading path on the decohesion is discussed. [less ▲]

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See detailThermal history modelling to understand microstructures observed in repair technology of Ti-6Al-4V
Tran, Hoang Son ULiege; Tchuindjang, Jérôme Tchoufack ULiege; Hakan, Paydas et al

in Extended Abstract book of 14th Conf. on Computer Methods in Materials Technology KomPlasTech 2017 (2017, January)

Laser cladding is a metal deposition technique used to fabricate or repair components. In the present work Ti-6Al-4V deposits with a variable thickness are studied to assess the use of laser cladding as a ... [more ▼]

Laser cladding is a metal deposition technique used to fabricate or repair components. In the present work Ti-6Al-4V deposits with a variable thickness are studied to assess the use of laser cladding as a repair technology [1]. Solidification following melting and partial remelting of pre-existing layers is coupled with heat treatment of the solidified material due to the repeated heating and cooling cycles during building. The effect of the building strategy on the metallurgical characteristics of the material for a decreasing track length (DTL) or a constant track length (CTL) strategy is analyzed. Depending on the possible heat accumulation, the nature of the phases are determined by metallography and hardness maps of the deposits. Optical Microscopy (OM), Stereo Microscopy (SM), and Scanning Electron Microscopy (SEM) were used in order to study the microstructure. The generation of the microstructure results from the material thermal history. This one is computed by Finite Element Method and a careful analysis establishes the link between the phase state and the detailed thermal history. [less ▲]

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See detailAssessment of corrosion resistance, material properties, and weldability of alloyed steel for ballast tanks
De Baere, Kris; Verstraelen, Helen; Willemen, Remke et al

in Journal of Marine Science & Technology (2017), 22(1), 176-199

Ballast tanks are of great importance in the lifetime of modern merchant ships. Making a ballast tank less susceptible to corrosion can, therefore, prolong the useful life of a ship and, thereby, lower ... [more ▼]

Ballast tanks are of great importance in the lifetime of modern merchant ships. Making a ballast tank less susceptible to corrosion can, therefore, prolong the useful life of a ship and, thereby, lower its operational cost. An option to reinforce a ballast tank is to construct it out of a corrosion-resistant steel type. Such steel was recently produced by POSCO Ltd., South Korea. After 6 months of permanent immersion, the average corrosion rate of A and AH steel (31 samples) was 535 g m−2 year−1, while the Korean CRS was corroding with 378 g m−2 year−1. This entails a gain of 29 %. Follow-up measurements after 10, 20, and 24 months confirmed this. The results after 6 months exposure to alternating wet/dry conditions are even more explicit. Furthermore, the physical and metallurgical properties of this steel show a density of 7.646 t/m3, the elasticity modulus 209.3 GPa, the tensile strength 572 MPa, and the hardness 169HV10. Microscopically, the metal consists of equiaxed and recrystallized grains (ferrite and pearlite), with an average size of between 20 and 30 µm (ASTM E 112—12 grain size number between 7 and 8) with a few elongated pearlitic grains. The structure is banded ferrite/pearlite. On the basis of a series of energy dispersive X-ray spectrometer measurements the lower corrosion rate of the steel can be attributed to the interplay of Al, Cr, their oxides, and the corroding steel. In addition, the role of each element in the formation of oxide layers and the mechanisms contributing to the corrosion resistance are discussed. [less ▲]

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See detailOn the Elaboration of Metal-Ceramic Composite Coatings by Laser Cladding
Mertens, Anne ULiege; L'Hoest, Thibaut; Magnien, Julien et al

in Materials Science Forum (2017), 879

This paper reports on a preliminary investigation into the elaboration, by the additive process known as laser cladding, of composite coatings with a matrix of stainless steel 316L reinforced with varying ... [more ▼]

This paper reports on a preliminary investigation into the elaboration, by the additive process known as laser cladding, of composite coatings with a matrix of stainless steel 316L reinforced with varying contents of tungsten (WC) or silicon carbides (SiC) particles. Laser cladding is characterised by ultra-fast solidification and cooling rates, thus giving rise to ultra-fine out-of-equilibrium microstructures and potentially enhanced mechanical properties. Both types of composite coatings – i.e. with SiC or WC ‒ are compared in terms of their microstructures and hardness. Special attention is given to the dissolution of the carbides particles and to interfacial reactions taking place between the particles and the metallic matrix. [less ▲]

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See detailLaser Cladding Finite Element Modelling Application to Ti6Al4V,
Tran, Hoang Son ULiege; Brusten, Romain; Jardin, Ruben et al

Conference (2016, November 03)

Corrélation entre les champs thermiques prédits et la microstructure observée.

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See detailOn the effect of microstructural anisotropy on the mechanical and thermophysical properties of Ti6Al4V processed by Laser Beam Melting
Mertens, Anne ULiege; Paydas, Hakan ULiege; Rigo, Olivier et al

Conference (2016, August 05)

Laser beam melting (LBM) is a strongly directional process in which a metallic powder is deposited layer by layer in a powder bed and molten locally according to the desired shape. When processing Ti6Al4V ... [more ▼]

Laser beam melting (LBM) is a strongly directional process in which a metallic powder is deposited layer by layer in a powder bed and molten locally according to the desired shape. When processing Ti6Al4V, it is well known that the latest layer tends to solidify epitaxially on the previous layers, thus giving rise to elongated columnar primary β(BCC) crystals extending over several successive layers. These primary β grains then transforms into the α(HCP) structure upon cooling. The present work aimed at studying the microstructural anisotropy of LBM Ti6Al4V, as well as its consequences on the mechanical and thermophysical properties (i.e. thermal expansion and thermal conductivity). In order to gain a deeper undestanding of thermal phenomena in the LBM of Ti6Al4V, great care was also taken to characterize the thermophysical properties over a wide temperature range from room temperature. [less ▲]

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See detailAlumina and zircon refractory ceramic molds fabrication by additive methods for metal alloys casting
Bister, Geoffroy; Hautcoeur, Dominique; Deschuyteneer, Dorian et al

Conference (2016, July 19)

Traditional processes for the foundry molds fabrication need numerous and rather time consuming steps. These processes are not really adapted to small series or prototypes. The research project exposed in ... [more ▼]

Traditional processes for the foundry molds fabrication need numerous and rather time consuming steps. These processes are not really adapted to small series or prototypes. The research project exposed in this contribution proposes an alternative method combining the advantages of molding (free formulation of metal alloys, economy on material and on time of machining) with those of the additive processes (short steps between 3D-model and final product, very complex geometries available). For short series the selective laser melting process (SLM) allows the building of molds in a very short time compared to the traditional investment casting method. This technique also permits the unique advantage to control the design of the shell thickness and structure in order to have a better control of the thermal fluxes during metal cooling. This would potentially ensure a better control of the casting defaults. In this presentation, molds built with alumina and zircon as raw materials will be presented. Two metallic alloys have been tested in order to validate alumina and zircon as mold materials; the first, AlCu4MgSi chosen as low melting point alloy reference and the second, stainless steel 316L, as high melting point alloy reference [less ▲]

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See detailOn the role of interfacial reactions, dissolution and secondary precipitation during the laser additive manufacturing of metal matrix composites - A Review
Mertens, Anne ULiege; Lecomte-Beckers, Jacqueline ULiege

in Shishkovsky, I.V. (Ed.) New Trends in 3D Printing (2016)

Since current trends in the transportation, energy or mechanical industries impose increasingly demanding service conditions for metallic parts, metal matrix composites (MMC) are the object of a growing ... [more ▼]

Since current trends in the transportation, energy or mechanical industries impose increasingly demanding service conditions for metallic parts, metal matrix composites (MMC) are the object of a growing interest. Powder-based laser additive manufacturing, that allows to make parts with complex shapes, appears particularly adapted for the production of MMCs. This paper reviews the current state-of-the-art in the production of MMCs by additive processes, with the aim of assessing the potentials and difficulties offered by these techniques. Two main processing routes are envisaged i.e. (1) the processing of ex-situ composites in which the reinforcing phase as a powder – often of ceramic particles − is directly mixed with the powder of the matrix alloy, and both powders are simultaneously processed by the laser. (2) Alternatively, the reinforcing phase can be produced in-situ by a chemical reaction during the fabrication of the composite. For both processing routes, a careful control is needed to overcome challenges brought e.g. by the behaviour of the reinforcement particles in the laser beam, by changes in laser absorptivity or by the dissolution of the reinforcing particles in the molten metal, in order to produce metal matrix composites with enhanced usage properties. [less ▲]

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