Effect of Free-fall Nozzle Channel Dispersion Angle on TC4 Discontinuous Droplets Pre-breakup in EIGA

Abstract

The effect of the inlet gas pressure, supplementary gas pressure and nozzle channel dispersion angle on the pre-breakup behavior of Ti-6Al-4V (TC4) discontinuous droplets during EIGA was investigated by combining numerical simulation with experiments. The results show that the axial velocity at the recirculation zone before the stagnation location was first increased and decreased then increased significantly after the peak value, while the pressure of the recirculation zone increased with the increase in inlet pressure. With the supplementary pressure increasing, the velocity magnitude and range of the recirculation zone gradually decreased. As the dispersion angle of the nozzle channel increased, the pre-breakup efficiency of droplets gradually decreased, but the adhesion phenomenon of droplets on the inner wall surface of the nozzle channel (IWSNC) gradually weakened. Under the inlet pressure of 4 MPa, a supplementary pressure of 0.05 MPa, and the dispersion angle of 15°, the uniform and spherical TC4 powders with diameter of 70 µm were prepared, which was consistent with the simulation results. The optimized process parameters is a balance between the size of the pre-atomized particles and the back-spraying and bonding phenomenons of droplets.

Keywords

discontinuous droplets / dispersion angle / numerical simulation / pre-breakup / EIGA

References

[1] Arcella FG, Froes FH. Producing Titanium Aerospace Components from Powder using Laser Forming[J]. JOM, 2000, 52: 28-30.

[2] Stevenson G, Rehman S, Draper E, et al. Combining 3D Human in Vitro Methods for a 3Rs Evaluation of Novel Titanium Surfaces in Orthopaedic Applications[J]. Biotechnol. Bioeng., 2016, 113(7): 1 586-1 599.

[3] Wang P, Li J, Liu HS, et al. Process Modeling Gas Atomization of Close-coupled Ring-hole Nozzle for 316L Stainless Steel Powder Production[J]. Chin. Phys. B, 2021, 30(5): 057 502

[4] Naveed Ahsan M, Pinkerton AJ, Moat RJ, et al. A Comparative Study of Laser Direct Metal Deposition Characteristics using Gas and Plasma-atomized Ti-6Al-4V Powders[J]. Materials Science & Engineering A, 2011, 528(25–26): 7 648-7 657.

[5] Shan F, Min X, Ge CC. Consecutive Induction Melting of Nickel-based Superalloy in Electrode Induction Gas Atomization[J]. Chin. Phy. B, 2017, 26(6): 060 201

[6] Spitans S, Franz H, Baake E. Numerical Modeling and Optimization of Electrode Induction Melting for Inert Gas Atomization (EIGA)[J]. Metall. Mater. Trans. B, 2020, 51: 1 918-1 927.

[7] Wang P, Li J, Wang X, et al. Impact Mechanism of Gas Temperature in Metal Powder Production via Gas Atomization[J]. Chin. Phys. B, 2021, 30(5): 054 702

[8] Henein H, Uhlenwinkel V, Fritsching U. Metal Sprays and Spray Deposition[M], 2017 New York: Springer.

[9] Lu LL, Zhang SM, Xu J, et al. Numerical Study of Titanium Melting by High Frequency Inductive Heating[J]. Int. J. Heat Mass Tran., 2017, 108(PartB): 2 021-2 028.

[10] Lubanska H. Correlation of Spray Ring Data for Gas Atomization of Liquid Metals[J]. JOM, 1970, 22: 45-49.

[11] Xia M, Wang P, Zhang XH, et al. Computational Fluid Dynamic Investigation of the Primary and Secondary Atomization of the Free-fall Atomizer in Electrode Induction Melting Gas Atomization Process[J]. Acta Physica Sinica(Chinese Edition), 2018, 67(17): 170 201

[12] Wang P, Li J, Wang X, et al. Close-coupled Nozzle Atomization Integral Simulation and Powder Preparation using Vacuum Induction Gas Atomization Technology[J]. Chin. Phys. B, 2021, 30(2): 027 502

[13] Zeoli N, Tabbara H, Gu S. Three-dimensional Simulation of Primary Break-up in a Close-coupled Atomizer[J]. Appl. Phys. A-Mater., 2012, 108: 783-792.

[14] Motaman S. High-speed Imaging and Computational Modelling of Close-coupled Gas Atomization[D], 2013 Leeds: University of Leeds.

[15] Motaman S, Mullis AM, Cochrane RF, et al. Numerical and Experimental Modelling of Back Stream Flow during Close-coupled Gas Atomization[J]. Computers & Fluids, 2013, 88: 1-10.

[16] Wei MW, Chen SY, Sun M, et al. Atomization Simulation and Preparation of 24CrNiMoY Alloy Steel Powder using VIGA Technology at High Gas Pressure[J]. Powder Technology, 2020, 367: 724-739.

[17] Duan AQ, Li C. Characteristics of Keyhole and Molten Pool during Laser Welding of TC4 Ti-alloy[C]. In: Proceedings of the 36th International MATADOR Conference, 2010

[18] Jouvard JM, Perret O, Naudy Ph. Keyhole Formation and Power Deposition in Nd:YAG Laser Spot Welding[C]. In: XIII International Symposium on Gas Flow and Chemical Lasers and High-power Laser Conference, 2001

[19] Ting J, Anderson IE. A Computational Fluid Dynamics (CFD) Investigation of the Wake Closure Phenomenon[J]. Materials Science and Engineering:A, 2004, 379(1–2): 264-276.

[20] Zeoli N, Gu S. Computational Simulation of Metal Droplet Break-up, Cooling and Solidification during Gas Atomisation[J]. Computational Materials Science, 2008, 43(2): 268-278.

[21] Zhao WJ, Cao FY, Ning ZL, et al. A Computational Fluid Dynamics (CFD) Investigation of the Flow Field and the Primary Atomization of the Close Coupled Atomizer[J]. Computers & Chemical Engineering, 2012, 40: 58-66.

[22] Fritsching U. Spray Simulation: Modelling and Numerical Simulation of Sprayforming Metals[M], 2004 New York: Cambridge University Press. 48-53.

[23] Zou HP, Xiao ZY. Pre-breakup Mechanism of Free-fall Nozzle in Electrode Induction Melting Gas Atomization[J]. Mateials Today Communications, 2021, 29: 1-11.