Numerical Analysis of Solidification Behavior during Laser Welding Nickel-Based Single-Crystal Superalloy Part I: Crystallography-Dependent Solid Aluminum Distribution

Abstract:

The thermal metallurgical modeling of alloying aluminum redistribution was further developed through couple of heat transfer model, dendrite selection model, multicomponent dendrtie grwoth model and nonequilibrium solidification model during three-dimensional nickel-based single-crystal superalloy weld pool solidification over a wide range of welding conditions (laser power, welding speed and welding configuration) to facilitate understanding of solidification cracking phenomena. It is indicated that the welding configuration plays more important role than heat input in aluminum redistribution. The bimodal distribution of solid aluminum concentration along the solid/liquid interface is crystallographically symmetrical about the weld pool centerline for (001) and [100] welding configuration, while the distribution of solid aluminum concentration along the solid/liquid interface is crystallographically asymmetrical throughout the weld pool for (001) and [110] welding configuration. The size of vulnerable [100] dendrite growth region is beneficially suppressed in favor of epitaxial [001] dendrite growth region through optimum low heat input (low laser power and high welding speed) to facilitate single-crystal dendrite growth for successful crack-free weld at the expense of shallow weld pool geometry. The overall aluminum concentration in (001) and [100] welding configuration is significantly smaller than that of (001) and [110] welding configuration regardless of heat input. Severe aluminum enrichment is confined to [100] dendrite growth region where is more susceptible to solidification cracking. Heat input and welding configuration are optimized in order to minimize the solidification cracking susceptibility and improve microstructure stability. The relationship between welding conditions and alloying aluminum redistribution are established for solidification cracking susceptibility evaluation. The higher heat input is used, the more aluminum enrichment is monotonically incurred by diffusion with considerable increase of metallurgical driving forces for morphology instability and microstructure anomalies to deteriorate weldability and vice versa. The mechanism of asymmetrical solidification cracking because of crystallography-dependent alloying redistribution is proposed. The theoretical predictions agree well with the experiment results. Moreover, the useful modeling is also applicable to other single-crystal superalloys with similar metallurgical properties during laser welding or laser cladding.

• Periodical: Materials Science Forum (Volume 1020)
• Pages: 13-22
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1020.13
• Online since: February 2021
• Authors: Zhi Guo Gao*
• Keywords: Crystallographic Orientation, Laser Welding, Numerical Analysis, Single-Crystal Superalloy, Solidification Cracking, Weldability

References

[1] Weiping Liu, J.N. Dupont. Effects of melt-pool geometry on crystal growth and microstructure development in laser surface-melted superalloy single crystals. Mathematical modeling of single-crystal growth in a melt pool (part I), Acta Materialia,52 (2004),4833-4847.

DOI: 10.1016/s1359-6454(04)00390-8

[2] Weiping Liu, J.N. Dupont. Effects of substrate crystallographic orientations on crystal growth and microstructure development in laser surface-melted superalloy single crystals. Mathematical modeling of single-crystal growth in a melt pool (part II), Acta Materialia,53 (2005),1545-1558.

DOI: 10.1016/j.actamat.2004.12.007

[3] D.Dye, O.Hunziker, R.C. Reed. Numerical analysis of the weldability of superalloys, Acta Mater., 49 (2001),683-697.

DOI: 10.1016/s1359-6454(00)00361-x

[4] O.Hunziker, D.Dye, R.C. Reed. On the formation of a centerline grain boundary during fusion welding, Acta Mater.,48 (2000),4191-4201.

DOI: 10.1016/s1359-6454(00)00273-1

[5] T.D. Anderson, J.N. Dupont, T.Debroy. Origin of stray grain formation in single-crystal superalloy weld pools from heat transfer and fluid flow modeling, Acta Materialia,58 (2010), 1441-1454.

DOI: 10.1016/j.actamat.2009.10.051

[6] T.D. Anderson, J.N. Dupont, T.Debroy. Stray grain formation in welds of single-crystal Ni-based superalloy CMSX-4,Metallurgical and Materials Transactions A, Vol.41A (2010),181-193.

DOI: 10.1007/s11661-009-0078-9

[7] M.Rappaz, S.A. David, J.M. Vitek, L.A. Boatner. Analysis of solidification microstructures in Fe-Ni-Cr single-crystal welds, Metallurgical Transactions A, Vol.21A (1990),1767-1782.

DOI: 10.1007/bf02672593

[8] M.Rappaz, S.A. David, J.M. Vitek, L.A. Boatner. Development of microstructures in Fe-15Ni-15Cr single crystal electron beam welds, Metallurgical Transactions A, Vol.20A (1989), 1125-1138.

DOI: 10.1007/bf02650147

[9] M. Rappaz, Ch.A. Gandin, Probabilistic modeling of microstructure formation in solidification processes, Acta Metall. Mater., Vol.41(2) (1993),345-360.

DOI: 10.1016/0956-7151(93)90065-z

[10] J.M. Vitek. The effect of welding conditions on stray grain formation in single crystal welds-theoretical analysis, Acta Materialia, 53 (2005),53-67.

DOI: 10.1016/j.actamat.2004.08.039

[11] S.S. Babu, M.K. Miller, J.M. Vitek, S.A. David. Characterization of the microstructure evolution in a nickel-based superalloy during continuous cooling conditions, Acta Mater.,49 (2001),4149- 4160.

DOI: 10.1016/s1359-6454(01)00314-7

[12] J.W. Park, S.S. Babu, J.M. Vitek, E.A. Kemik, S.A. David. Stray grain formation in single crystal Ni-based superalloy welds, Journal of Applied Physics, Vol.94(6) (2003),4203-4209.

DOI: 10.1063/1.1602950

[13] N.L. Richard, M.C. Chaturvedi. Effect of minor elements on weldability of nickel-based superalloys, International Materials Review, Vol.45(3) (2000),109-129.

DOI: 10.1179/095066000101528331

[14] R.K. Sidhu, O.A. Ojo, M.C. Chaturvedi. Microstructural analysis of laser beam-welded directionally solidified INCONEL 738, Metallurgical and Materials Transactions A,Vol.38A (2007), 858-870.

DOI: 10.1007/s11661-006-9063-8

[15] Y.L. Wang, O.A. Ojo, R.G. Ding, M.C. Chaturvedi. Weld metal in laser beam welded single crystal nickel-based superalloys, Materials Science and Technology, Vol.25(1) (2009),68-75.

DOI: 10.1179/174328407x185938

[16] S.N. Tewari, M.Vijayakumar, J.E. Lee, P.A. Curreri. Solutal partition coefficients in nickel-based super alloy PWA1480,Materials Science and Engineering A, 141 (1996),1-2.

DOI: 10.1016/0921-5093(91)90713-w

[17] N.Wang, S.Mokadem, M.Rappaz, W.Kurz. Solidification cracking superalloy single- and bi- crystals, Acta Materialia, 52 (2004),3173-3182.

DOI: 10.1016/j.actamat.2004.03.047

[18] R.J. Moat, A.J. Pinkerton, L.Li, P.J. Withers, M.Preuss. Crystallographic texture and microstructure of pulsed diode laser-deposited Waspaloy, Acta Materialia, 57 (2009), 1220-1229.

DOI: 10.1016/j.actamat.2008.11.004

[19] M.Gaumann, C.Bezencon, P.Canalis, W.Kurz. Single-crystal laser deposition on superalloys: processing-microstructure maps, Acta Mater., 49 (2001),1051-1062.

DOI: 10.1016/s1359-6454(00)00367-0

[20] A.Wagner, B.A. Shollock, M.Mclean. Grain structure development in directional solidification of nickel-based superalloys. Materials Science and Engineering A, 374 (2004),270-279.

DOI: 10.1016/j.msea.2004.03.017

[21] X.L. Yang, H.B. Dong, W.Wang, P.D. Lee. Microscale simulation of stray grain formation in investment cast turbine blades, Materials Science and Engineering A, 386 (2004),129-139.

DOI: 10.1016/s0921-5093(04)00914-1

[22] A.de Bussac, Ch.A. Gandin. Prediction of a process window for the investment casting of dendritic single crystals. Materials Science and Engineering A, 237 (1997),35-42.

DOI: 10.1016/s0921-5093(97)00081-6

[23] Edward H. Kottcamp. ASM Handbook, Volume 3, Alloy phase diagrams, ASM International, USA,1993,49-155.

[24] Wu Qiong, Li Shusuo, Ma Yue, Gong Shengkai. First principles calculations of alloying element diffusion coefficient in Ni using the five-frequency model, Chin.Phys.B, Vol.21 (10) (2012), 1091021-1-7.

DOI: 10.1088/1674-1056/21/10/109102

[25] J.M. Vitek, S.S. Babu, J.W. Park, S.A. David. Analysis of stray grain formation in single-crystal nickel-based superalloy welds. Proceeding of International Symposium on Superalloys,2004, 459-465.

DOI: 10.7449/2004/superalloys_2004_459_465

[26] J.M. Vitek, S.A. David, S.S. Babu. Optimization of weld conditions and alloy composition for welding single-crystal nickel-based superalloys. Materials Science Forum,Vol.539-543 (2007), 3082-3087.

DOI: 10.4028/www.scientific.net/msf.539-543.3082