Surface Formation Mechanisms in Selective Laser Melting of Cobalt-Chromium-Molybdenum Powder

Abstract:

Selective laser melting (SLM) is a manufacturing technology of metal parts of any shapes with target mechanical properties by means of laser melting. This paper discusses the effect of SLM parameters: laser output power, laser movement velocity, scanning pitch and preheating temperature of a powdered material on surface formation mechanism, namely, its physical configuration when melting cobalt-chromium-molybdenum powdered material Со28Cr3Mo. The study points at structural differences of melted surfaces even under identical process parameters. Several types of surface formation are identified, e.g. homogenous melt, coagulated particles, and shapeless particles. Vapor pressure, Marangoni effect, and heat effect of a melted powder are stated to be key reasons for rough surface. This research is of high importance for understanding the effect of SLM parameters on formation of a target quality surface, positive stability and repeatable accuracy of the process.

• Periodical: Key Engineering Materials (Volume 839)
• Pages: 73-78
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.839.73
• Online since: April 2020
• Authors: Alexandr Saprykin*, Yuriy Sharkeev, Natalya Saprykina, Egor Ibragimov
• Keywords: Coagulation, Cobalt-Chromium-Molybdenum, Melting Conditions, Quality, Selective Laser Melting (SLM)

References

[1] Y. Lu, S. Wu, Y. Gan, J. Li, C. Zhao, D. Zhuo, J. Lin, Investigation on the microstructure, mechanical property and corrosion behavior of the selective laser melted CoCrW alloy for dental application, Mater. Sci. Eng.: C 49 (2015) 517–525.

DOI: 10.1016/j.msec.2015.01.023

[2] B. Song, S. Dong, Q. Liu, et al., Vacuum heat treatment of iron parts produced by selective laser melting: microstructure, residual stress and tensile behavior, Mater. Des. 54 (2014) 727–733.

DOI: 10.1016/j.matdes.2019.108335

[3] A. A. Saprykin, N. A. Saprykina, Improvement of surface layer formation technology for articles produced by layer-by-layer laser sintering, Applied Mechanics and Materials. 379 (2013) 56-59.

DOI: 10.4028/www.scientific.net/amm.379.56

[4] J.-H. Cho, S.-J. Na, Implementation of real-time multiple reflection and Fresnel absorption of laser beam in keyhole, J. Phys. D: Appl. Phys. 39 (24) (2006)5372.

DOI: 10.1088/0022-3727/39/24/039

[5] A. Takaichi, T. Nakamoto, N. Joko, et al., Microstructures and mechanical properties of Co–29Cr–6Mo alloy fabricated by selective laser melting process for dental applications, J. Mech. Behav. Biomed. Mater. 21 (2013) 67–76.

DOI: 10.1016/j.jmbbm.2013.01.021

[6] B. Song, S. Dong, B. Zhang, et al., Effects of processing parameters on microstructure and mechanical property of selective laser melted Ti6Al4V[J], Mater. Des. 35 (2012) 120–125.

DOI: 10.1016/j.matdes.2011.09.051

[7] D. Dai, D. Gu, Thermal behavior and densification mechanism during selective laser melting of copper matrix composites: simulation and experiments [J], Mater. Des. 55 (2014) 482–491.

DOI: 10.1016/j.matdes.2013.10.006

[8] A. Simchi, Direct laser sintering of metal powders: mechanism, kinetics and microstructural features [J], Mater. Sci. Eng. A 428 (1) (2006) 148–158.

DOI: 10.1016/j.msea.2006.04.117

[9] S. Leuders, M. Thöne, A. Riemer, et al., On the mechanical behaviour of titanium alloy TiAl6V4 manufactured by selective laser melting: fatigue resistance and crack growth performance, Int. J. Fatigue. 48 (2013) 300–307.

DOI: 10.1016/j.ijfatigue.2012.11.011

[10] Y. Kajima, A. Takaichi, N. Kittikundecha, T. Nakamoto, T. Kimura, N. Nomura, A. Kawasaki, T. Hanawa, H. Takahashi, N. Wakabayashi, Effect of heat-treatment temperature on microstructures and mechanical properties of Co–Cr–Mo alloys fabricated by selective laser melting, Mater. Sci. Eng. 726 (2018) 21–31.

DOI: 10.1016/j.msea.2018.04.048

[11] A. S. Yanyushkin, О. I. Medvedeva, N. A. Saprykina, Mechanism of Protective Membrane Formation on the Surface of Metal-Bonded Diamond Disks, Applied Mechanics and Materials. 682 (2014) 327-331.

DOI: 10.4028/www.scientific.net/amm.682.327

[12] A. A. Saprykin, N. A. Saprykina, D. V. Dudikhin, S. M. Emelyanenko, Influence of layer-by-layer laser sintering modes on the thickness of sintered layer of cobalt-chromium-molybdenum powder, Advanced Materials Research. 1040 (2014) 805-808.

DOI: 10.4028/www.scientific.net/amr.1040.805

[13] A. A. Saprykin, E. A. Ibragimov , E. V. Babakova, Modeling the Temperature Fields of Copper Powder Melting in the Process of Selective Laser Melting, IOP Conference Series: Materials Science and Engineering. 142(1) (2016) 012061.

DOI: 10.1088/1757-899x/142/1/012061

[14] Y. Liu, Y. Yang, S. Mai, et al., Investigation into spatter behavior during selective laser melting of AISI 316 L stainless steel powder, Mater. Des. 87 (2015) 797–806.

DOI: 10.1016/j.matdes.2015.08.086

[15] A. A. Saprykin, N. A. Saprykina, Engineering support for improving quality of layer-by-layer laser sintering, 7th International Forum on Strategic Technology IFOST. (2012) 6357719.

DOI: 10.1109/ifost.2012.6357719

[16] C. Song, M. Zhang, Y. Yang, D. Wang, Y. Jia-kuo, Morphology and properties of CoCrMo parts fabricated by selective laser melting, Mater. Sci. Eng.: A 713 (2018) 206–213.

DOI: 10.1016/j.msea.2017.12.035

[17] A. Ladewig, G. Schlick, M. Fisser, V. Schulze, U. Glatzel, Influence of the shielding gas flow on the removal of process by-products in the selective laser melting process, Addit. Manuf. 10 (2016) 1–9.

DOI: 10.1016/j.addma.2016.01.004

[18] A. A. Saprykin, E. A. Ibragimov , E. V. Babakova, V. I. Yakovlev, Influence of mechanical activation of copper powder on physicomechanical changes in selective laser sintering products, AIP Conference Proceedings. 1683 (2015) 020199.

DOI: 10.1063/1.4932889

[19] S.A. Khairallah, A.T. Anderson, A. Rubenchik, et al., Laser powder-bed fusion additive manufacturing: physics of complex melt flow and formation mechanisms of pores, spatter, and denudation zones, Acta Mater. 108 (2016) 36–45.

DOI: 10.1016/j.actamat.2016.02.014