This study presents a comprehensive molecular dynamics (MD) investigation into the atomic-scale material removal behavior and the concomitant surface and subsurface damage mechanisms in single-crystal nickel (Ni) subject to argon (Ar) ion beam sputtering. The research systematically explores the influence of critical processing parameters, specifically sputtering energy (600 eV, 1 000 eV, and 1 400 eV), ion dose (1.562 5×1013 ions/cm² and 3.125 0×1013 ions/cm2), and incident angle (30°, 45°, 60°, 75°, and 90°), on the evolution of surface topography, strain field distribution, subsurface defect generation, and sputtering yield of the single crystal Ni (001) surface. MD simulations are conducted using the LAMMPS package with accurately calibrated interatomic potentials, providing detailed insights into the femtosecond-scale dynamics of ion-target interactions.
The simulation results unequivocally demonstrate that Ar ion beam sputtering produces distinct surface modifications characterized by the formation of nanoscale pits and adjacent atomic pile-ups within the core sputtered region. Concurrently, substantial subsurface damage manifests in the form of amorphous atomic clusters and crystallographic defects which are identified as {111}-plane stacking faults. These microstructural alterations are accompanied by significant strain concentration in the irradiated zone, with the magnitude and spatial distribution of strain being profoundly influenced by the specific processing parameters employed. Quantitative analysis establishes clear correlations between processing conditions and resultant damage characteristics. The pit area, the population of piled-up surface atoms, the proportional volume of amorphous material, the density of stacking fault atoms, the maximum depth of subsurface damage, and the peak strain values all exhibit a consistent and marked increase with escalating sputtering energy and accumulated ion dose.
There is a particularly noteworthy finding concerning the pivotal role of incident angle in modulating damage morphology and material removal efficiency. The most extensive surface and subsurface damage, in terms of both defect density and penetration depth, occurs at an incident angle of 60°. This optimal damage condition is attributed to the most effective synergy between the momentum components perpendicular and parallel to the target surface, facilitating maximum energy transfer and lattice disruption. In contrast, the sputtering yield, defined as the number of removed Ni atoms per incident Ar ion, follows a different angular dependence. It increases progressively with both energy and dose, reaching its absolute maximum at a shallower incidence angle of 30°. This peak removal efficiency is rationalized by a "shovel-sputtering effect," wherein the substantial parallel momentum component at shallow angles promotes efficient lateral displacement and ejection of surface atoms. Temporal analysis of the relaxation process further reveals that the initially generated strain concentrations and a considerable fraction of the stacking faults are not stable; they gradually dissipate and annihilate during subsequent thermal equilibration, highlighting the dynamic nature of defect evolution post-irradiation.
The collective findings underscore that ion beam processing parameters exert a profound and deterministic influence on the surface integrity, subsurface damage state, and material removal kinetics in single crystal Ni. The damage severity escalates systematically with increasing sputtering energy and ion fluence, while the incident angle dictates the balance between penetration-driven damage and surface-layer ejection efficiency. The observation that the most severe structural degradation (at 60°) is decoupled from the condition of maximum material removal rate (at 30°) provides crucial insight for process optimization. This detailed atomic-scale understanding of the interplay between processing parameters, defect generation, and material removal mechanisms offers valuable theoretical guidance and a robust predictive framework for the experimental optimization of ion beam processing techniques, particularly for high-precision machining and surface engineering applications of metallic single crystals and related advanced materials.
Key words
ion beam machining /
single crystal /
surface damage /
sputtering yield /
molecular dynamics
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References
[1] 周济. 智能制造--“中国制造2025”的主攻方向[J]. 中国机械工程, 2015, 26(17): 2273-2284.
ZHOU J.Intelligent Manufacturing—Main Direction of "Made in China 2025"[J]. China Mechanical Engineering, 2015, 26(17): 2273-2284.
[2] HORST O M, ADLER D, GIT P, et al.Exploring the Fundamentals of Ni-Based Superalloy Single Crystal (SX) Alloy Design: Chemical Composition Vs. Microstructure[J]. Materials & Design, 2020, 195: 108976.
[3] KONG T, DO J, KIM Y K, et al.Mechanical Properties of Ni-Based Single-Crystal Superalloy at 4.2 K[J]. Materials Science and Engineering: A, 2025, 942: 148679.
[4] MARKL M, MÜLLER A, RITTER N, et al. Development of Single-Crystal Ni-Base Superalloys Based on Multi-Criteria Numerical Optimization and Efficient Use of Refractory Elements[J]. Metallurgical and Materials Transactions A, 2018, 49(9): 4134-4145.
[5] 夏斯伟, 周海, 徐晓明, 等. 单晶材料纳米加工的分子动力学模拟研究进展[J]. 金刚石与磨料磨具工程, 2018, 38(5): 78-86.
XIA S W, ZHOU H, XU X M, et al.Advances in Molecular Dynamics Simulation of Nano-Manufacturing of Monocrystalline Materials[J]. Diamond & Abrasives Engineering, 2018, 38(5): 78-86.
[6] LEE T Y, CHEN P T, HUANG C C, et al.Advances in Core Technologies for Semiconductor Manufacturing: Applications and Challenges of Atomic Layer Etching, Neutral Beam Etching and Atomic Layer Deposition[J]. Nanoscale Advances, 2025, 7(10): 2796-2817.
[7] MIKHAILENKO M S, PESTOV A E, CHKHALO N I, et al.Influence of Ion-Beam Etching by Ar Ions with an Energy of 200-1000?eV on the Roughness and Sputtering Yield of a Single-Crystal Silicon Surface[J]. Applied Optics, 2022, 61(10): 2825-2833.
[8] LI R X, ELICEIRI M H, LI J G, et al.Optical Emission Spectroscopy and Gas Kinetics of Picosecond Laser-Induced Chlorine Dissociation for Atomic Layer Etching of Silicon[J]. The Journal of Physical Chemistry C, 2025, 129(5): 2460-2466.
[9] COSTANTINI G, RUSPONI S, MONGEOT F B D, et al. Periodic Structures Induced by Normal-incidence Sputtering on Ag(110) and Ag(001): Flux and Temperature Dependence[J]. Journal of Physics Condensed Matter, 2001, 13(26): 5875.
[10] VALBUSA U, BORAGNO C, BUATIER DE MONGEOT F. Nanostructuring by Ion Beam[J]. Materials Science and Engineering: C, 2003, 23(1/2): 201-209.
[11] BERNHEIM M, SLODZIAN G.Effect of Oxygen on the Sputtering of Aluminium Targets Bombarded with Argon Ions[J]. International Journal of Mass Spectrometry and Ion Physics, 1973, 12(1): 93-99.
[12] KARMAKAR P, GHOSE D.Ion Beam Sputtering Induced Ripple Formation in Thin Metal Films[J]. Surface Science, 2004, 554(2/3): L101-L106.
[13] MISHRA P, GHOSE D.Formation of Nanoripples in Al Films during O2+ Sputtering[J]. Physical Review B, 2006, 74(15): 155427.
[14] MISHRA P, GHOSE D.The Energy Dependence of Sputtering Induced Ripple Topography in Al Film[J]. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2008, 266(8): 1635-1641.
[15] MISHRA P, GHOSE D.Effect of Initial Target Surface Roughness on the Evolution of Ripple Topography Induced by Oxygen Sputtering of Al Films[J]. Journal of Applied Physics, 2009, 105: 014304.
[16] GAILLY P, PETERMANN C, TIHON P, et al.Ripple Topography and Roughness Evolution on Surface of Polycrystalline Gold and Silver Thin Films under Low Energy Ar-Ion Beam Sputtering[J]. Applied Surface Science, 2012, 258(19): 7717-7725.
[17] LIU F S, REN H T, PENG S X, et al.Effect of Crystal Orientation on Low Flux Helium and Hydrogen Ion Irradiation in Polycrystalline Tungsten[J]. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2014, 333: 120-123.
[18] BAUER J, FROST F.Orientation-Dependent Nanostructuring of Titanium Surfaces by Low-Energy Ion Beam Erosion[J]. Surface and Interface Analysis, 2020, 52(12): 1071-1076.
[19] BAUER J, FROST F, ARNOLD T.Reactive Ion Beam Figuring of Optical Aluminium Surfaces[J]. Journal of Physics D: Applied Physics, 2017, 50(8): 085101.
[20] BAUER J.Finishing of Metal Optics by Ion Beam Technologies[J]. Optical Engineering, 2019, 58(9): 1.
[21] BAUER J, ULITSCHKA M, FROST F, et al.Figuring of Optical Aluminium Devices by Reactive Ion Beam Etching[J]. EPJ Web of Conferences, 2019, 215: 06002.
[22] THOMPSON A P, AKTULGA H M, BERGER R, et al.LAMMPS-a Flexible Simulation Tool for Particle-Based Materials Modeling at the Atomic, Meso, and Continuum Scales[J]. Computer Physics Communications, 2022, 271: 108171.
[23] EVANS D J, HOLIAN B L.The Nose-Hoover Thermostat[J]. The Journal of Chemical Physics, 1985, 83(8): 4069-4074.
[24] ZHOU X W, JOHNSON R A, WADLEY H N G. Misfit-Energy-Increasing Dislocations in Vapor-Deposited CoFe/NiFe Multilayers[J]. Physical Review B, 2004, 69(14): 144113.
[25] GRANBERG F, NORDLUND K, ULLAH M W, et al.Mechanism of Radiation Damage Reduction in Equiatomic Multicomponent Single Phase Alloys[J]. Physical Review Letters, 2016, 116(13): 135504.
[26] ZIEGLER J F, ZIEGLER M D, BIERSACK J P.SRIM-the Stopping and Range of Ions in Matter (2010)[J]. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2010, 268(11/12): 1818-1823.
[27] STUKOWSKI A.Visualization and Analysis of Atomistic Simulation Data with OVITO-The Open Visualization Tool[J]. Modelling and Simulation in Materials Science and Engineering, 2010, 18(1): 015012.
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