Predicting the effect of cooling rates and initial hydrogen concentrations on porosity formation in Al-Si castings

Abstract

Al-Si alloys are widely used in automotive casting components while microporosity has always been a detrimental defect that leads to property degradation. In this study, a coupled three-dimensional cellular automata (CA) model has been used to predict the hydrogen porosity as functions of cooling rate and initial hydrogen concentration. By quantifying the pore characteristics, it has been found that the average equivalent pore diameter decreases from 40.43 to 23.98 µm and the pore number density increases from 10.3 to 26.6 mm^–3 as the cooling rate changes from 2.6 to 19.4°C/s at the initial hydrogen concentration of 0.25 mL/100 g. It is also notable that the pore size increases as the initial hydrogen concentration changes from 0.15 to 0.25 mL/100 g while the pore number remains stable. In addition, the linear regression between secondary dendrite arm spacing and the equivalent pore diameter has been studied for the first time, matching well with experiments. This work exhibits the application of CA model in future process optimization and robust condition design for advanced automotive parts made of Al-Si alloys.

Keywords

Al-Si alloy / cellular automata / cooling rate / microporosity / secondary dendrite arm spacing / solidification

References

[1] Hu MD, Wang TT, Fang H, Zhu MF. Modeling of the gas porosity and microstructure formation during dendritic and eutectic solidification of ternary Al-Si-Mg alloys. J Mater Sci Technol. 2021;76:76-85.

[2] Wang B, Zhang MS, Wang JS. Quantifying the effects of cooling rates and alloying additions on the microporosity formation in Al alloys. Mater Today Commun. 2021;28:102524.

[3] Jeon JH, Bae DH. Effect of cooling rate on the thermal and electrical conductivities of an A356 sand cast alloy. J Alloys Compd. 2019;808:151756.

[4] Biswas P, Das S, Das SC, Paliwal M, Roy H, Mondal MK. Thermochemical modelling and mechanical property of the Al-7.6Si-xZr alloy. Mater Sci Technol. 2023;39(18):3229-3243.

[5] Biswas P, Gupta S, Mondal MK, Bhandari R, Pramanik S. Structureproperty correlation of hypoeutectic Al-7.6Si alloys with and without Al-5Ti-1B grain refiner. J Sci Ind Res. 2020;79:696-700.

[6] Zhang QY, Wang TT, Yao ZJ, Zhu MF. Modeling of hydrogen porosity formation during solidification of dendrites and irregular eutectics in Al-Si alloys. Materialia. 2018;4:211-220.

[7] Di Giovanni MT, De Menezes JT, Cerri E, Castrodeza EM. Influence of microstructure and porosity on the fracture toughness of Al-Si-Mg alloy. J Mater Res Technol. 2020;9(2):1286-1295.

[8] Lee PD, Hunt JD. Hydrogen porosity in directionally solidified aluminium-copper alloys: a mathematical model. Acta Mater. 2001;49(8):1383-1398.

[9] Atwood RC, Lee PD. Simulation of the three-dimensional morphology of solidification porosity in an aluminium–silicon alloy. Acta Mater. 2003;51(18):5447-5466.

[10] Li KD, Chang E. Mechanism of nucleation and growth of hydrogen porosity in solidifying A356 aluminum alloy: an analytical solution. Acta Mater. 2004;52(1):219-231.

[11] Hannard F, Pardoen T, Maire E, Le Bourlot C, Mokso R, Simar A. Characterization and micromechanical modelling of microstructural heterogeneity effects on ductile fracture of 6xxx aluminium alloys. Acta Mater. 2016;103:558-572.

[12] Bogdanoff T, Tiryakioğlu M, Jarfors A, Seifeddine S, Ghassemali E. On the combined effects of surface quality and pore size on the fatigue life of Al-7Si-3Cu-Mg alloy castings. Mater Sci Eng A. 2023;885:145618.

[13] Arcía-Moreno F, Jürgens M, Banhart J. Temperature dependence of film rupture and internal structural stability in liquid aluminium alloy foams. Acta Mater. 2020;196:325-337.

[14] Toda H, Hidaka T, Kobayashi M, Uesugi K, Takeuchi A, Horikawa K. Growth behavior of hydrogen micropores in aluminum alloys during high-temperature exposure. Acta Mater. 2009;57(7):2277-2290.

[15] Chaijaruwanich A, Lee PD, Dashwood RJ, Youssef YM, Nagaumi H. Evolution of pore morphology and distribution during the homogenization of direct chill cast Al–Mg alloys. Acta Mater. 2007;55(1):285-293.

[16] Felberbaum M, Rappaz M. Curvature of micropores in Al–Cu alloys: an X-ray tomography study. Acta Mater. 2011;59(18):6849-6860.

[17] Lee PD, Chirazi A, See D. Modeling microporosity in aluminumsilicon alloys: a review. J Light Met. 2001;1:15-30.

[18] Wang JS, Lee PD. Simulating the tortuous 3D morphology of microporosity formed during solidification of Al-Si-Cu alloys. Int J Cast Met Res. 2007;20(3):151-158.

[19] Zhu MF, Li ZY, An D, Zhang QY, Dai T. Cellular automaton modeling of microporosity formation during solidification of aluminum alloys. ISIJ Int. 2014;54(2):384-391.

[20] Zhang YX, Xue CP, Yang XH, et al. Uncovering the effects of local pressure and cooling rates on porosity formation in AA2060 Al-Li alloy. Mater Today Commun. 2023;35:106348.

[21] Zhang YX, Xue CP, Wang JS, et al. Quantifying the effects of hydrogen concentration and cooling rates on porosity formation in Al-Li alloys. J Mater Res Technol. 2023;26:1938-1954.

[22] Li XX, Yang XH, Xue CP, et al. Predicting hydrogen microporosity in long solidification range ternary Al-Cu-Li alloys by coupling CALPHAD and cellular automata model. Comput Mater Sci. 2023;222:112120.

[23] Li XX, Yang XH, Xue CP, et al. Hydrogen microporosity evolution and dendrite growth during long solidification of Al-Cu-Li alloys: modeling and experiment. J Mater Process Technol. 2023;321:118135.

[24] Kirkwood DH. A simple model for dendrite arm coarsening during solidification. Mater Sci Eng. 1985;73:1-4.

[25] Osório WR, Garcia A. Modeling dendritic structure and mechanical properties of Zn–Al alloys as a function of solidification conditions. Mater Sci Eng A. 2002;325(1-2):103-111.

[26] Jegede O, Haque N, Mullisa A, Cochrane R. Relationship between cooling rate and SDAS in liquid phase separated metastable Cu-Co alloys. J Alloys Compd. 2021;883:160823.

[27] Jin ZH, Jia LN, WangLiu WBYY, Qi Y, Zhang H. Effect of cooling rate on microstructure and properties of SiC_p/A359 composites. Mater Des. 2023;234:112297.

[28] Liu XX, Wang B, Li Q, et al. Quantifying the effects of grain refiners (AlTiB and Y) on microstructure and properties in W319 alloys. Mater Today Commun. 2022;33:104671.

[29] Eliezer Ramirez-Vidaurri L, Castro-Roman M, Herrera-Trejo M, Fraga-Chavez K. Secondary dendritic arm spacing and cooling rate relationship for an ASTM F75 alloy. J Mater Res Technol. 2022;19:5049-5065.

[30] Vandersluis E, Ravindran C. Comparison of measurement methods for secondary dendrite arm spacing. Metallogr Microstruct Anal. 2017;6(1):89-94.

[31] Gu C, Lu Y, Luo AA. Three-dimensional visualization and quantification of microporosity in aluminum castings by X-ray microcomputed tomography. J Mater Sci Technol. 2021;65:99-107.

[32] Atwood RC, Lee PD. A Combined Cellular Automaton and Diffusion Model for the Prediction of Porosity Formation During Solidification. Imperial College London;2000.

[33] Wang JS. In-situ Observation and Mathematical Modelling of the Nucleation and Growth of Intermetallics and Hydrogen Porosities During the Solidification of Aluminum Alloys. Imperial College London;2009.

[34] Qiu K, Wang RC, Peng CQ, Lu XX, Wang NG. Polynomial regression and interpolation of thermodynamic data in Al-Si-Mg-Fe system. Calphad. 2015;48:175-183.

[35] Shin DW, Roy S, Watkins TR, Shyam A. Lattice mismatch modeling of aluminum alloys. Comput Mater Sci. 2017;138:149-159.

[36] Wang W, Lee PD, McLean M. A model of solidification microstructures in nickel-based superalloys: predicting primary dendrite spacing selection. Acta Mater. 2003;51(10):2971-2987.

[37] Lashkari O, Yao L, Maijer L, Maijer D. X-ray microtomographic characterization of porosity in aluminum alloy A356. Metall Mater Trans A. 2009;40(4):991-999.

[38] Gu C, Lu Y, Colin DR, Emre C, Alan AL. Three-dimensional cellular automaton simulation of coupled hydrogen porosity and microstructure during solidification of ternary aluminum alloys. Sci Rep. 2019;9(1):13099.

[39] Ye HZ. An overview of the development of Al-Si-alloy based material for engine applications. J Mater Eng Perform. 2003;12(3):288-297.

[40] Mitrasinovic A, Robles Hernández FC, Djurdjevic M, Sokolowski JH. On-line prediction of the melt hydrogen and casting porosity level in 319 aluminum alloy using thermal analysis. Mater Sci Eng A. 2006;428(1-2):41-46.

RIGHTS & PERMISSIONS

2024 The Author(s). Materials Genome Engineering Advances published by Wiley-VCH GmbH on behalf of University of Science and Technology Beijing.