Papers by Keyword: Metal Powders

Abstract: The properties of dampers manufactured by the selective laser melting are investigated. Microswear with different elastic and plastic properties were found. The texture of dampers samples represents a non-uniform supplement structure of crushed grains, separated by layers with dispersoids of crystallization of varying completion stages.

Abstract: Additive manufacturing is a new approach to solving the problems of creating high-performance instrument components. This article is devoted to the solution of the narrowly directed problem of surfacing metal powder 321L using the LENS method on the solenoid valve core. The core is made of electrical steel, in which a complex groove is machined. The difficulty of this work was to accurately perform the geometry of the melt layer that is not standard for this method. As a result, the product was obtained according to a completely new approach to its design, which subsequently gave increased operational characteristics of the final product. The article presents the problems that can be encountered when performing complex crevice surfacing on a complex groove. The structure of the deposited layer is considered, defects characteristic of this method in the form of interlayer pores, unalloyed powder particles are identified and described. The LENS process control modes are presented in order to reduce defects and improve the development of surfacing geometry.

Abstract: It was studied the structure of hard magnetic alloys Fe-Cr-Co and Al-Ni-Cu-Co-Fe manufactured by selective laser melting (SLM) from spherical powders smaller than 80 microns on the RussianSLM FACTORY unit. Powders were manufactured by melt atomization. At various scanning speeds and laser powers, samples were made to study the structure, magnetic and mechanical parameters. By constructing a hysteresis loop, data were obtained indicating an increase in the magnetic characteristics in SLM samples in comparison with similar ones obtained by foundry technology.

Abstract: The development of additive manufacturing (SLS/SLM, EBM, DMD) suggests the increase of the range expansion of materials used. One of the most promising directions is products manufacturing from composite materials. The technology of composite micro-powders production on the basis of heat-resistant nickel alloy EP648 and TiC is proposed. The aim of this research is to develop a method of producing composite micropowders for additive technology application. This method is based on modification of the metal micropowders surface by the second phase in a planetary mixer (mechanochemical synthesis).The obtained composite micropowders are compared with powders which are recommended for selective laser melting usage (produced by MTT Technology). The equipment used in the research: planetary mixer, scanning electron microscopy (SEM), optical granulomorphometer Occio 500nano.

Abstract: The technology of composite micropowders’ obtaining that allows the production of a wide range of composite powders suitable for use in additive technologies is proposed. The technology includes modification of the metal powder surface with the mechanochemical treatment. The production modes for the AlSi12-Al₂O₃ composite powder are determined.

Abstract: Selective Laser Sintering/Selective Laser Melting (SLS/SLM) is one of Additive Manufacturing (AM) processes that utilize layer by layer powder deposition technique and successive laser beam irradiation based on Computer Aided Design (CAD) data. During laser irradiation on metal powders, melt pool was formed, which then solidified to consolidated structure. Therefore, melt pool is an important behavior that affects the final quality of track formation. The study investigates the melt pool behavior through visualization of the consolidation process during the single track formation on the first layer. In order to understand the transformation process of metal powder to consolidated structure and mechanism involved, high speed camera was used to monitor the process. Yb:fiber laser beam was irradiated on metal powder at maximum power of 150W. The laser processing parameters such as laser power, scan speed and layer thickness were varied in order to investigate their influence on the consolidation process. The result shows the size of melt pool increased with laser power and decreasing with increment in scan speed. Furthermore, with the increase of layer thickness, melt pool formation was unstable with chaotic movement. Significant amount of molten powder splattering was recorded from the melt pool. At high layer thickness also, the molten powder formed spherical shaped and the solidified molten powder failed to wet with the substrate.

Abstract: The work pertains to research of inhomogeneity level of the composite compacts manufactured from flaky metal particles and polymer binder. In the present investigation, magnetically hard Nd-Fe-B powders were used. The composite matrix was in all cases polystyrene. Volume fraction of the powders in composites was 40 ÷ 54%. As the forming method injection moulding was used. Granulates were obtained from powders and polystyrene dissolved with toluene. Produced cylindrical specimens had 10 mm in diameter and 4 mm in height. The structure of specimens was determined on the basis on quantitative analysis of the micrographs of axial sections. The analysis of binary images of metallographic specimens allowed to determine homogeneity and directions of flake distribution. Standard deviation of surface fraction is a measure of inhomogeneity which shows relatively well both local and general differences in the distribution of particles. The greater the volume of powder V_p in composites, the lower standard deviation S. The size of particles also influences the value of standard deviation. The greater the size of particles in a composite, the greater the values of S. In the next research, information about inhomogeneity will be useful in estimation of distribution of mechanical and magnetic parameters of the compacts (dielectromagnets) formed in this way.

Abstract: The objective of this study is to investigate the surface roughness that effect the capability of adhesive with adding aluminium powder and 63/37 Sn-Pb soft solder powder to the epoxy to increase the mechanical strength of joints. The adhesive strength of the joints was determined by utilizing the single-lap shear test. As seen from the experiments, the surface roughness has an important effect on the strength of adhesive bonded joints. Experimental results show that joints prepared by adhesive which was modified, adding in the amount of 5 wt% 63/37 Sn-Pb powder have more mechanical strength than joints compared to one which is prepared by adding aluminium powder with different ratios as 5, 25,50 wt%.