Effect of Powder Type and Particles Size on Microstructure of Selective Laser Sintered Parts

2019 ◽  
Vol 799 ◽  
pp. 252-256
Author(s):  
Simonas Mindaugas Jankus ◽  
Regita Bendikiene

The goal of this work was to investigate microstructure of the selective laser sintering (SLS) produced parts evaluating effect of powder type and fraction size. Studies have shown that printed samples of 316L and GP1 metal powders had a higher defect content compared to printed components from MP1 powder material. From scanning electron microscopy (SEM), it was found that iron-based printed parts melted worse than Co-Cr alloy components. Iron-based 316L and GP1 metal powders did not get enough energy from laser to perform a better microwelding between particles. Surface roughness Ra numerical values for samples 316L, GP1, MP1 respectively are Ra = 13.7 μm; 11.4 μm; 3.0 μm. Stainless steel powder material contains particles which size varies between 20 – 120 μm. The Co-Cr alloy and the maraging steel powder materials are made of 10 – 80 μm particles. The chemical and elemental composition of powder materials were examined using SEM-EDS technology.

2021 ◽  
Vol 877 (1) ◽  
pp. 012009
Author(s):  
Mohammed Qasim Kareem ◽  
Vladimir Dorofeyev

Abstract It is possible to expand the applications ranges of powder material products by enhancing the performance properties of these products in addition to their manufacturability and reliability together, it’s possible by materials structures modification. In this paper, the effect of fullerene (C60) additives to iron-based powder material has been studied. All samples produced by Hot-Forging (HF) powder materials technology. Green and HF density of the obtained samples calculated by volume / weight and Archimede’s principle, respectively. The effect of technological parameters on the microstructure of carbon steels’ samples was done by an ALTAMI MET-1M metallographic microscope. Tensile test executed by using of a universal testing machine UMM –5 and the microhardness (HV10) was measured by REICHERT hardness test machine. The results showed that the HF C60 steels’ samples had higher density and strength of 0.81 and 25%, respectively, with a good plasticity in comparison with graphite steels’ samples.


2015 ◽  
Vol 667 ◽  
pp. 218-223
Author(s):  
Yue Qiang Yu ◽  
Yan Ling Guo ◽  
Kai Yi Jiang

In view of the physical process of the wood powder/PES composite powder material selective laser sintering forming ,this article establishes the plane moving Gaussian heat source as the input laser heat source model .Based on selective laser sintering wood powder/PES composite powder sintering theory and combined with thermal conductivity of composite powder, specific heat, density and other related theoretical analytical models .It establishes three dimensional finite element model of selective laser sintering process of wood powder/PES composite powder transient temperature field .The laser sintering simulation experiment of wood powder/PES composite powder under different laser power obtains temperature field distribution law of the wood powder/PES composite powder forming under different laser power distribution, and the influence of the forming parts forming quality of wood powder/PES composite powder materials caused by the temperature field. The simulation results also provide certain theoretical basis for the choice of laser power in the subsequent laser sintering experiment.


Author(s):  
Dinar R. Masalimov ◽  
Roman R. Galiullin ◽  
Rinat N. Sayfullin ◽  
Azamat F. Fayurshin ◽  
Linar F. Islamov

There are a number of difficulties in the electrical contact welding of powder materials: shedding of powder from the surface of a cylindrical part, impossibility of hardening the layer during welding due to flushing of the powders with coolant and unstable flow of powder into the welding zone. One solution is pre-spraying the powder in some way. (Research purpose). The research purpose is investigating the possibility of electric contact welding of metal powders preliminarily sprayed by a gas-flame method, namely, adhesion strength and losses during preliminary gas-flame spraying of powders. (Materials and methods) Powders of grades PG-NA-01, PrKhIIG4SR, PRZh3.200.28 were sprayed onto flat samples of St3 steel, polished to a roughness of Ra 1.25. The strength of powder adhesion to the base was studied by the cut method. (Results and discussion) The percentage loss of the powder as a whole is 3-23 percent for all the distances studied. The greatest powder losses appear at a distance of more than 180 millimeter from the tip of the burner for powders of grades PG-NA-01 and PrKhIIG4SR. The smallest powder losses were observed for PrZh3.200.28 powder, which totaled 3-7 percent. The maximum adhesion strength of the sprayed powders to the surface was 22.1 megapascals' when spraying the PG-NA-01 powder. The adhesion strength of powders of the grades PrKhIIG4SR and PrZh3.200.28 is small and amounts to 0.2-3 megapascals'. (Conclusions) The use of preliminary flame spraying of powders for their further electric contact welding is possible using PG-NA-01 grade powder, while the best adhesion to the base (that is more than 20 megapascals') is achieved with a spraying distance of 120-140 millimeter. The smallest powder losses during flame spraying are achieved at a spraying distance of 100-160 centimeters', at which the powder loss for the studied grades was 4-12 percent.


2017 ◽  
Vol 902 ◽  
pp. 60-64
Author(s):  
Judith Alejandra Velázquez Perez ◽  
Wilfrido Martínez Molina ◽  
Hugo Luis Chávez García ◽  
Elia Mercedes Alonso Guzmán ◽  
Rosalía Ruiz Ruiz

This research is an investigation about the use of powder material additions with mortars lime base for a possible implementation in construction and/or restoration of historical sites. Mortars were elaborated in laboratory conditions with a 1:2.5 in weight proportion. One of the proofs to which these mortars were submitted was the test of capillary absorption; this way, the influence of the materials added to powder in these mortars determined porosity. Mortars were made with different percentages of materials. These powder materials are brick manufacturing ash, quarry powder, clay and maize starch. The test was run during 350 to 700 days. It obtained better results with 700 days than with 350 days.


Author(s):  
D. V. Minko

The possibility of selective laser sintering of graded porous and compactly porous structures by surface fusion of powder particles is demonstrated while maintaining a solid core, which leads to the formation of interparticle contacts in the presence of a liquid phase. The interaction of the light flux of the laser pulse with the surface of the powder particles under multiple reflection is considered. It is shown that the effect of single pulses of laser radiation leads to the formation of sintered structural elements of a powder material having a diameter approximately equal to the diameter of the focal spot. Technological regimes of pulsed laser action are established at which steady contact formation of titanium powder particles of the fractional compositions under study occurs. The possibility of obtaining powder materials with a gradient structure by controlling the parameters of pulsed laser action is experimentally demonstrated. It was found that accurate dosing of thermal energy and the number of pulses of laser radiation makes it possible to minimize shrinkage of powder layers in the absence of particle conglomeration, to control the structural characteristics and properties of products, to preserve the microstructure and phase composition of the initial materials.


Author(s):  
E. V. Ageeva ◽  
B. N. Sabel’nikov

The first appearance of tungsten-free hard alloys (TFHA) was noted in the early 30s of the last century, but they did not receive due attention and, accordingly, spread due to insufficient strength and were replaced by tungsten-containing alloys of such groups as VK, TC and TTK. However, the rapidly developing shortage of expensive tungsten pushed in the late 50s to return to the search for hard alloys, the composition of which does not include tungsten. Due to the growing demand for tungsten-free hard alloys, the problem of recycling their waste with the possibility of reuse is acute in the industry. The purpose of this work was to conduct x-ray spectral microanalysis (RSMA) of powder material (PM) obtained by electroerosive dispersion (EED) in ethyl alcohol from waste of a non-tungsten hard alloy of the KNT16 brand. The resulting powder material was examined using an energy-dispersion x-ray analyzer from EDAX, built into a scanning electron microscope "QUANTA 600 FEG". In the course of scientific research, the spectra of characteristic x-ray radiation on the surface of the experimentally obtained sample were obtained. The results obtained in the course of scientific research can be used to create environmentally friendly resource-saving processes for processing waste of tungsten-free hard alloys into powder materials.


1988 ◽  
Vol 27 (10) ◽  
pp. 805-809
Author(s):  
O. V. Evtushenko ◽  
S. M. Chernega

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