On the Substructure Development and Continuous Recrystallization in the Course of Selective Laser Melting of 316L Stainless Steel

Document Type : Research Paper

Authors

School of Metallurgy & Materials Engineering, Iran University of Science and Technology (IUST), Tehran, Iran

Abstract

In the present work, the selective laser melting (SLM) has been chosen as a controlled thermomechanical processing route in which the required temperature and strain for the occurrence of dynamic recrystallization is provided. The 316L stainless steel as representative material was constructed by SLM under specified parameters (laser power, layer thickness, hatch spacing, scan strategy, and scan speed). The printed material’s microstructure was carefully analyzed through electron back scattered diffraction. The presence of considerable fine grains (< 20 μm) through the printed microstructure was considered as evidence for the occurrence of dynamic recrystallization during the manufacturing process. The high fraction of sub-boundaries (~79.7%) and sub-grains indicted the capability of the material for substructure development in the course of additive manufacturing process, and the fact that the new fine grains were formed through continuous dynamic recrystallization mechanism. The creation of plastic strains through the parts structure during SLM, which was required for dynamic recrystallization, was discussed relying on the expansion and contraction of the layers during repeated heating and cooling cycles. The amount of plastic microstrain was estimated to be around ~0.56 considering the layer thickness and depth of the melt pool. The hot compression tests were conducted at 1000℃ and various strain rates of 0.001, 0.01 and 0.1 s-1 and the corresponding critical strains of dynamic recrystallization (~0.2) were calculated, which was well lower than those created during additive manufacturing process.

Keywords


[1]    W.E. Frazier, Metal additive manufacturing: a review, Journal of Materials Engineering and Performance, 23 (2014) 1917-1928.
[2]    F. Bartolomeu, S. Faria, O. Carvalho, E. Pinto, N. Alves, F.S. Silva, G. Miranda, Predictive models for physical and mechanical properties of Ti6Al4V produced by Selective Laser Melting, Materials Science and Engineering: A, 663 (2016) 181-192.
[3]    S.L. Sing, J. An, W.Y. Yeong, F.E. Wiria, Laser and electron‐beam powder‐bed additive manufacturing of metallic implants: A review on processes, materials and designs, Journal of Orthopaedic Research, 34(3) (2016) 369-385.
[4]    A.N. Chen, J.M. Wu, K. Liu, J.Y. Chen, H. Xiao, P. Chen, C.H. Li, Y.S. Shi, High-performance ceramic parts with complex shape prepared by selective laser sintering: a review, Advances in Applied Ceramics, 117(2) (2018) 100-117.
[5]    Y. Kok, X.P. Tan, P. Wang, M.L.S. Nai, N.H. Loh, E. Liu, S.B. Tor, Anisotropy and heterogeneity of microstructure and mechanical properties in metal additive manufacturing: A critical review, Materials & Design, 139 (2018) 565-586.
[6]    F. Bartolomeu, M. Buciumeanu, E. Pinto, N. Alves, O. Carvalho, F.S. Silva, G. Miranda, 316L stainless steel mechanical and tribological behavior—A comparison between selective laser melting, hot pressing and conventional casting, Additive Manufacturing, 16 (2017) 81-89.
[7]    T. DebRoy, H.L. Wei, J.S. Zuback, T. Mukherjee, J.W. Elmer, J.O. Milewski, A.M. Beese, A. Wilson-Heid, A. De, W. Zhang, Additive manufacturing of metallic components–process, structure and properties, Progress in Materials Science, 92 (2018) 112-224.
[8]    R. Motallebi, Z. Savaedi, H. Mirzadeh, Additive manufacturing–a review of hot deformation behavior and constitutive modeling of flow stress, Current Opinion in Solid State and Materials Science, 26(3) (2022) 100992.
[9]    L.E. Murr, S.M. Gaytan, D.A. Ramirez, E. Martinez, J. Hernandez, K.N. Amato, P.W. Shindo, F.R. Medina, R.B. Wicker, Metal fabrication by additive manufacturing using laser and electron beam melting technologies, Journal of Materials Science & Technology, 28(1) (2012) 1-14.
[10]  O. Zinovieva, A. Zinoviev, Numerical analysis of the grain morphology and texture in 316L steel produced by selective laser melting, In: AIP Conference Proceedings, 2167 (2019) 020407.
[11]  A. Rai, M. Markl, C. Körner, A coupled cellular automaton–lattice Boltzmann model for grain structure simulation during additive manufacturing, Computational Materials Science, 124 (2016) 37-48.
[12]  C. Herriott, X. Li, N. Kouraytem, V. Tari, W. Tan, B. Anglin, A.D. Rollett, A.D. Spear, A multi-scale, multi-physics modeling framework to predict spatial variation of properties in additive-manufactured metals, Modelling and Simulation in Materials Science and Engineering, 27(2) (2019) 025009.
[13]  R. Shi, S.A. Khairallah, T.T. Roehling, T.W. Heo, J.T. McKeown, M.J. Matthews, Microstructural control in metal laser powder bed fusion additive manufacturing using laser beam shaping strategy, Acta Materialia, 184 (2020) 284-305.
[14]  O. Zinovieva, A. Zinoviev, V. Ploshikhin, Three-dimensional modeling of the microstructure evolution during metal additive manufacturing, Computational Materials Science, 141 (2018) 207-220.
[15]  A. Baumard, D. Ayrault, O. Fandeur, C. Bordreuil, F. Deschaux-Beaume, Numerical prediction of grain structure formation during laser powder bed fusion of 316 L stainless steel, Materials & Design, 199 (2021) 109434.
[16]  K.M. Bertsch, G.M. De Bellefon, B. Kuehl, D.J. Thoma, Origin of dislocation structures in an additively manufactured austenitic stainless steel 316L, Acta Materialia, 199 (2020) 19-33.
[17]  N. Chen, G. Ma, W. Zhu, A. Godfrey, Z. Shen, G. Wu, X. Huang, Enhancement of an additive-manufactured austenitic stainless steel by post-manufacture heat-treatment, Materials Science and Engineering: A, 759 (2019) 65-69.
[18]  P. Bajaj, A. Hariharan, A. Kini, P. Kürnsteiner, D. Raabe, E.A. Jägle, Steels in additive manufacturing: a review of their microstructure and properties, Materials Science and Engineering: A, 772 (2020) 138633.
[19]  O.O. Salman, C. Gammer, A.K. Chaubey, J. Eckert, S. Scudino, Effect of heat treatment on microstructure and mechanical properties of 316L steel synthesized by selective laser melting, Materials Science and Engineering: A, 748 (2019) 205-212.
[20]  S. Waqar, J. Liu, Q. Sun, K. Guo, J. Sun, Effect of post-heat treatment cooling on microstructure and mechanical properties of selective laser melting manufactured austenitic 316L stainless steel, Rapid Prototyping Journal, 26(10) (2020) 1739-1749.
[21]       M. Güden, S. Enser, M. Bayhan, A. Taşdemirci, H. Yavaş, The strain rate sensitive flow stresses and constitutive equations of a selective-laser-melt and an annealed-rolled 316L stainless steel: a comparative study, Materials Science and Engineering: A, 838 (2022) 142743.
[22]  S.P. Kumar, V. Chakkravarthy, A. Mahalingam, R. Rajeshshyam, N. Sriraman, P. Marimuthu, R.L. Narayan, P.D. Babu, Investigation of crystallographic orientation and mechanical behaviour in laser-welded stainless steel 316L additive components, Transactions of the Indian Institute of Metals, 76(2) (2023) 527-535. 
[23]  M. Fousová, D. Dvorský, A. Michalcová, D. Vojtěch, Changes in the microstructure and mechanical properties of additively manufactured AlSi10Mg alloy after exposure to elevated temperatures, Materials Characterization, 137 (2018) 119-126.
[24]  Y. Li, D. Gu, Parametric analysis of thermal behavior during selective laser melting additive manufacturing of aluminum alloy powder, Materials & Design, 63 (2014) 856-867.
[25]  K. Saeidi, X. Gao, Y. Zhong, Z.J. Shen, Hardened austenite steel with columnar sub-grain structure formed by laser melting, Materials Science and Engineering: A, 625 (2015) 221-229.
[26]  J. Song, Y. Chew, G. Bi, X. Yao, B. Zhang, J. Bai, S.K. Moon, Numerical and experimental study of laser aided additive manufacturing for melt-pool profile and grain orientation analysis, Materials & Design, 137 (2018) 286-297.
[27]  J. Suryawanshi, K.G. Prashanth, U. Ramamurty, Mechanical behavior of selective laser melted 316L stainless steel, Materials Science and Engineering: A, 696 (2017) 113-121.
[28]  A. Ahmadi, R. Mirzaeifar, N.S. Moghaddam, A.S. Turabi, H.E. Karaca, M. Elahinia, Effect of manufacturing parameters on mechanical properties of 316L stainless steel parts fabricated by selective laser melting: a computational framework, Materials & Design, 112 (2016) 328-338.
[29]  J.P. Kruth, J. Deckers, E. Yasa, R. Wauthlé, Assessing and comparing influencing factors of residual stresses in selective laser melting using a novel analysis method, Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 226(6) (2012) 980-991.
[30]  T. Simson, A. Emmel, A. Dwars, J. Böhm, Residual stress measurements on AISI 316L samples manufactured by selective laser melting, Additive Manufacturing, 17 (2017) 183-189.
[31]  H.E. Sabzi, X.H. Li, C. Zhang, H. Fu, D. San-Martín, P.E.J. Rivera-Díaz-del-Castillo, Deformation twinning-induced dynamic recrystallization during laser powder bed fusion, Scripta Materialia, 207 (2022) 114307.
[32]  E.I. Poliak, J. Jonas, A one-parameter approach to determining the critical conditions for the initiation of dynamic recrystallization, Acta Materialia, 44(1) (1996) 127-136.