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Krakhmalev P.,Karlstad University | Yadroitsev I.,National School of Engineering, Saint-Etienne
Intermetallics | Year: 2014

Transition metal silicides and carbides are attractive advanced materials possessing unique combinations of physical and mechanical properties. However, conventional synthesis of bulk intermetallics is a challenging task because of their high melting point. In the present research, titanium carbides and silicides composites were fabricated on the titanium substrate by a selective laser melting (SLM) of Ti-(20,30,40 wt.%)SiC powder mixtures by an Ytterbium fiber laser with 1.075 μm wavelength, operating at 50 W power, with the laser scanning speed of 120 mm/s. Phase analysis of the fabricated coatings showed that the initial powders remelted and new multiphase structures containing TiCx, Ti5Si3Cx, TiSi2 and SiC phases in situ formed. Investigation of the microstructure revealed two main types of inhomogeneities in the composites, (i) SiC particles at the interlayer interfaces and, (ii) chemical segregation of the elements in the central areas of the tracks. It was suggested and experimentally proven that an increase in laser power to 80 W was an efficient way to improve the laser penetration depth and the mass transport in the liquid phase, and therefore, to fabricate more homogeneous composite. The SLM Ti-(20,30,40 wt.%)SiC composites demonstrated high hardness (11-17 GPa) and high abrasive wear resistance (3.99 × 10-7-9.51 × 10-7g/Nm) properties, promising for the applications involving abrasive wear. © 2013 Elsevier Ltd. All rights reserved.

École Centrale Lyon, French National Center for Scientific Research, University of Lyon and National School of Engineering, Saint-Etienne | Date: 2011-11-08

The present invention relates to a device for characterizing mechanical properties of a material (S) with a low modulus of elasticity, comprising an application surface (

Agency: Cordis | Branch: FP7 | Program: CSA-SA | Phase: NMP.2012.4.0-2 | Award Amount: 682.65K | Year: 2012

SASAMs mission is to drive the growth of AM to efficient and sustainable industrial processes by integrating and coordinating Standardisation activities for Europe by creating and supporting a Standardisation organisation in the field of AM. The Additive Manufacturing (AM) concept is based on additive freeform fabrication technologies for the automated production of complex products. Additive Manufacturing is defined as the direct production of finished goods using additive processes from digital data. A key advantage is that AM eliminates the need for tooling, such as moulds and dies, that can make the introduction of new products prohibitively expensive, both in time and money. This enables the production of forms that have been long considered impossible by conventional series productionin fact, they can be created fast, flexibly, and with fewer machines.

Yadroitsev I.,National School of Engineering, Saint-Etienne | Krakhmalev P.,Karlstad University | Yadroitsava I.,National School of Engineering, Saint-Etienne
Journal of Alloys and Compounds | Year: 2014

Selective laser melting (SLM) is a kind of additive manufacturing where parts are made directly from 3D CAD data layer-by-layer from powder material. SLM products are used in various industries including aerospace, automotive, electronic, chemical, biomedical and other high-tech areas. The properties of the parts produced by SLM depend strongly on the material nature, characteristics of each single track and each single layer, as well as the strength of the connections between them. Studying the temperature distribution during SLM is important because temperature gradient and heat transfer determine the microstructure and finally mechanical properties of the SLM part. In this study a CCD camera was applied for determination of the surface temperature distribution and the molten pool size of Ti6Al4V alloy. The investigation of the microstructure evolution after different heat treatments was carried out to determine the microstructure in terms of applicability for the biomedical industry. © 2013 Elsevier B.V. All rights reserved.

Yadroitsev I.,National School of Engineering, Saint-Etienne | Krakhmalev P.,Karlstad University | Yadroitsava I.,National School of Engineering, Saint-Etienne | Johansson S.,Linkoping University | Smurov I.,National School of Engineering, Saint-Etienne
Journal of Materials Processing Technology | Year: 2013

Process parameters of selective laser melting affect the response of a powder-substrate system and, therefore, the geometry and microstructure of the manufactured parts. The experiments were carried out at fixed values of laser power (50 W), spot diameter (70 μm) and powder layer thickness (80 μm). In this research, influence of the energy input parameters (80-900 °C preheating temperature and 0.08-0.28 m/s laser scanning speed) on micro structure and geometry of single tracks fabricated of stainless steel grade 316L powder was analysed. Both factors were found statistically significant with regard to their influence on the remelted depth and the primary cell spacing in the colonies observed in the tracks cross-sections. More specifically, the contact angle and track height were controlled by the preheating temperature, and track width and contact zone characteristics were governed by the laser scanning speed. Because of the threshold behaviour of these two factors, values starting with 700 °C and 0.24 m/s were found not optimal and causing instability and balling effect. Conclusions regarding the selection of process parameters for the formation of tracks with the desired geometry and micro structure were formulated based on statistical analysis of the experimental data. © 2012 Elsevier B.V. All rights reserved.

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