Influence of SLM-process parameters on the formation of the boundaries of parts of heat-resistant nickel alloy Inconel 718

1Adzhamskiy, SV, 2Kononenko, GА, 3Podolskyi, RV
1Oles Honchar Dnipro National University, Dnipro, Ukraine; LLC «Additive Laser Technology of Ukraine», Dnipro, Ukraine
2Z.I. Nekrasov Iron and Steel Institute of the National Academy of Sciences of Ukraine, Dnipro, Ukraine; LLC «Additive Laser Technology of Ukraine», Dnipro, Ukraine
3Z.I. Nekrasov Iron and Steel Institute of the National Academy of Sciences of Ukraine, Dnipro, Ukraine; National Metallurgical Academy of Ukraine, Dnipro, Ukraine
Space Sci. & Technol. 2021, 27 ;(6):105-114
https://doi.org/10.15407/knit2021.06.105
Язык публикации: English
Аннотация: 
We consider the improvement is considered of the modes of selective laser melting technology based on the design model to reduce the level of residual stresses and prevent deviations in the geometry of the part. Simulation results are presented on a universal voxel structure and a simplified object to predict metal behavior depending on the specific energy density in the region of the boundaries of a metal part made of Inconel 718. An experiment was carried out to study the influence of different strategies and process modes on the curvature of parts as a result of the effect of residual stresses in order to minimize them. Printing was carried out on a 3-D printer "Alfa-150" (LLC "ALT Ukraine") at constant power (P, W) and distance between tracks (d, mm) in each zone (up-skin, down-skin, in - skin) with a change in the speed (V, mm / s) of the laser beam movement, as well as a different pattern of sample growth by 3-D printing with 67 degrees rotation of each new layer relative to the previous one. To identify defects and deviations from the original model to the solid (sample), metallographic analysis was performed using optical microscopy (Carl Zeiss AXIOVERT 200M).
        It was found that the simulation of printing processes, performed on the Magics platform by breaking the model into a voxel structure, allows an analytical assessment of stresses and strains. Analysis of the appearance of the prototypes showed that the best down-skin indicators are formed at a power of 80 W and a specific energy density (40 ... 38 J / mm3). By using the 67 degrees staggered printing strategy at the optimum specific energy density, it is possible to minimize the residual internal stresses leading to distortion of the product. In the future, the results can be supplemented by studies of the effect of residual stresses of compressive forces when exposed to a laser beam at  constant applied power. Using a computational model that allows calculating the residual stresses during the deposition of the next layer, depending on the speed of the laser, the power and the distance between the applied tracks, it is possible to obtain high-precision parts with specified properties.
         The adaptation of the model, which allows us to obtain a quantitative estimate of the residual thermal stresses depending on the speed of movement and the laser power for the Inconel 718 heat-resistant alloy, has been carried out. Optimal modes have been determined to minimize these stresses and reduce the curvature of the part.
Ключевые слова: compression force, inconel 718, laser, residual stresses, selective laser melting
References: 
1. Adzhamskiy S. V., Kononenko A. A., Podol’skiy R. V. (2020). Research of the influence of the SLM-process modes on the quality in the area of the product contour. Materials of the International Science and Technology Conference “University Science-2020” (May 20-21, 2020, Mariupol). Mariupol, 157—158 [in Russian].
2. Adzhamskij S. V., Kononenko A. A., Podol’skij R. V. (2020). Simulation of the influence of residual stresses and parameters of SLM-technology on the formation of the area of product boundaries from the heat-resistant nickel alloy Inconel 718. Materials of the International Science and Technology Conference “Information Technology metallurgy and machine-building” (17-19 March 2020, Dnipro). Dnipro, 4—6.
DOI: https://doi.org/10.34185/1991-7848.itmm.2020.01.001 [in Russian]
3. Grekova M. V., Kalinin A. V., Dzhur E. A., Nosova T. V. (2019). Complex modification of multicomponent alloys. Space Science and Technology, 25 (3), 25-31.
https://doi.org/10.15407/knit2019.03.025
4. Adzhamskij S. V., Kononenko A. A., Podol’skij R. V. (2020). Two-dimensional modeling of a non-stationary temperature field of a single track made of heat-resistant alloy INCONEL 718. Materials of the All-Ukrainian scientific-methodical conference “Problems of mathematical modeling” (May 27-28, 2020, Kam’yanske). Kam’yanske, 42—45 [in Russian].
5. Parida A. K., Maity K. (2018). Comparison the machinability of Inconel 718, Inconel 625 and Monel 400 in hot turning operation. Eng. Sci. and Technol., Int. J., 21, 364—370.
6. Criales L. E., Arısoy Y. M., Lane B., et al. (2017). Laser powder bed fusion of nickel alloy 625: experimental investigations of effects of process parameters on melt pool size and shape with spatter analysis. Int. J. Mach. Tools Manuf., 121, 22—36.
7. Zhouab Y. H., Wanga Y. P., Zhangab Z. H. (2019). Selective laser melting of typical metallic materials: An effective process prediction model developed by energy absorption and consumption analysis. Additive Manufacturing, 25, 204—217.
8. Grasso M., Colosimo B. M. (2017). Process defects and in situ monitoring methods in metal powder bed fusion: a review. Measurement Sci. and Technol., 28, 1—25.
9. Williams R. J., Piglione A., Rønneberg T., Jones C., Pham M.-S., Davies C. M., Hooper P. A. (2019). In situ thermography for laser powder bed fusion: Effects of layer temperature on porosity, microstructure and mechanical properties. Additive Manufacturing, 1—14.
10. Shiomi M., Osakada K., Nakamura K., Yamashita T., Abe F. (2004). Residual stress within metallic model made by selective laser melting process. CIRP Annals Manufacturing Technology, 53 (1), 195—198.
11. Wang D. et al. (2012). Study on energy input and its influences on single-track, multi-track, and multi-layer in SLM. Int. J. Adv. Manuf. Technol., № 58, 1189—1199
12. Dilip J. S., Zhang S., Teng C., et al (2017). Influence of processing parameters on the evolution of melt pool, porosity, and microstructures in Ti-6Al-4V alloy parts fabricated by selective laser melting. Progress in Additive Manufacturing, № 2, 157—167.
https://doi.org/10.1007/s40964-017-0030-2
13. Zheng B. et al. (2008). Thermal behavior and microstructure evolution during laser deposition with laser-engineered net shaping: Part II. Experimental investigation and discussion. Metall. Mater. Trans. A Phys. Metall. Mater. Sci., 39 (9), 2237—2245.