Investigation on mechanism of nano-machining of single-crystal silicon carbide on non-continuous surface with diamond abrasive
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摘要: 建立金刚石磨料纳米加工单晶碳化硅衬底的分子动力学模型,从矢量位移、切削力、晶体结构相变及缺陷等方面研究划痕对原子去除过程的影响以及划痕壁面的材料去除机理。结果表明:划痕区域原子的去除方法主要是剪切和挤压。划痕入口区壁面变形为弹性和塑性混合变形,划痕出口区壁面变形主要为塑性变形,增加纳米加工深度能够提高原子的去除量。衬底表面存在的划痕使纳米加工过程中的切向和法向切削力均降低,最大差值分别为300和600 nN,划痕区域原子的缺失是切向力下降的主要原因。磨粒的剪切挤压作用使碳化硅原子的晶体结构发生了非晶转化,产生了大量不具有完整晶格的原子,并且衬底表层的原子与临近的原子成键,形成稳定的结构。衬底温度受影响的区域主要集中在磨粒的下方,并向衬底的深处传递,在2、5和8 Å纳米加工深度下衬底温度之间的差值约为100 K。Abstract: The molecular dynamics model of nano-machining a single-crystal silicon carbide substrate with a diamond abrasive is established. The effect of scratch on the atomic removal process and the material removal mechanism of the scratch wall were studied, considering vector displacement, cutting force, crystal structure transformation, and defects. The results show that the main methods for removing atoms in the scratched area are cutting and extrusion. The wall deformation of the scratch inlet zone invloves elastic and plastic mixed deformation, while the wall deformation of the scratch outlet zone is mainly plastic deformation. Increasing machining depth improves the removal of atoms. The presence of scratches on the substrate surface reduces both tangential and normal cutting forces in the nano-machining process, with the maximum difference being about 300 nN and 600 nN, respectively. The absence of atoms in the scratch area is the main reason for the decrease in tangential forces. The crystal structure of silicon carbide atoms is transformed by the shear and extrusion of the abrasive, resulting in a large number of atoms without a complete lattice. Moreover, atoms on the substrate surface form a stable structure by bonding with neighboring atoms. The affected area of substrate temperature is mainly concentrated under the abrasive and transferred to the depth of the substrate, with a difference of about 100 K between the substrate temperature at 2 Å, 5 Å, and 8 Å nano-machining depths.
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表 1 纳米加工过程中分子动力学模拟的条件
Table 1. The parameters of molecular dynamics simulation in nano-machining process
参数 值 磨粒半径/Å 20 磨粒的原子数 5 887 衬底的尺寸/Å3 200 × 100 × 80 衬底的原子数 145 264 纳米加工的深度/Å 2、5、10 纳米加工的距离/Å 200 时间步长/fs 1 初始温度/K 298 划痕尺寸/Å3 20 × 100 × 20 磨粒速度/(m•s-1) 100 -
[1] SHEN J F, CHEN H B, CHEN J P, et al. Mechanistic difference between Si-face and C-face polishing of 4H-SiC substrates in aqueous and non-aqueous slurries [J]. Ceramics International,2023,49(5):7274-7283. doi: 10.1016/j.ceramint.2022.10.193 [2] 何艳, 苑泽伟, 段振云, 等. 单晶碳化硅晶片高效超精密抛光工艺 [J]. 哈尔滨工业大学学报,2019,51(1):115-121.HE Yan, YUAN Zewei, DUAN Zhenyun, et al. High-productively ultraprecise polishing technology of single crystal silicon carbide wafer [J]. Journal of Harbin Institute of Technology,2019,51(1):115-121. [3] GAO X J, LI X, HE Y, et al. Investigation on electrical enhanced photocatalysis polishing of single-crystal silicon carbide substrates [J]. International Journal of Precision Engineering and Manufacturing,2022,23(11):1261-1274. doi: 10.1007/s12541-022-00708-0 [4] TIAN Z, LU J, LUO Q, et al. Chemical reaction on silicon carbide wafer (0001 and 000-1) with water molecules in nanoscale polishing [J]. Applied Surface Science,2023,607:155090. doi: 10.1016/j.apsusc.2022.155090 [5] TSAI M Y, HOO Z T. Polishing single-crystal silicon carbide with porous structure diamond and graphene-TiO2 slurries [J]. The International Journal of Advanced Manufacturing Technology,2019,105(1-4):1519-1530. doi: 10.1007/s00170-019-04223-x [6] DENG H, LIU N, ENDO K, et al. Atomic-scale finishing of carbon face of single crystal SiC by combination of thermal oxidation pretreatment and slurry polishing [J]. Applied Surface Science,2018(434):40-48. [7] YUAN Z, HE Y, SUN X, et al. UV-TiO2 photocatalysis-assisted chemical mechanical polishing 4H-SiC wafer [J]. Materials & Manufacturing Processes,2018,33(11):1214-1222. [8] HE Y, YUAN Z, TANG M, et al. Mechanism of chemical and mechanical mutual promotion in photocatalysis-assisted chemical mechanical polishing for single-crystal SiC [J]. Proceedings of the Institution of Mechanical Engineers, Part C:Journal of Mechanical Engineering Science,2022,236(24):11464-11478. doi: 10.1177/09544062221117953 [9] WANG J C, CHI H R, ZHAO Y. Effect of silicon carbide hard particles scratch on the diamond cutting tools groove wear [J]. Proceedings of the Institution of Mechanical Engineers Part C-Journal of Mechanical Engineering Science,2020,234(10):2053-2063. doi: 10.1177/0954406219900199 [10] HU Z W, CHEN Y, LAI Z Y, et al. Coupling of double grains enforces the grinding process in vibration-assisted scratch: Insights from molecular dynamics [J]. Journal of Materials Processing Technology,2022,304:117551. doi: 10.1016/j.jmatprotec.2022.117551 [11] FENG R C, YANG S G, SHAO Z H, et al. Atomistic Simulation of Effects of Random Roughness on Nano-cutting Process of y-TiAl Alloy [J]. Rare Metal Materials and Engineering,2022,51(5):1650-1659. [12] FENG R C, QIAO H Y, ZHU Z X, et al. Molecular Dynamics Simulations of Single Crystal gamma-TiAl Alloy in Nanometric Cutting Process [J]. Rare Metal Materials and Engineering,2019,48(5):1559-1566. [13] WANG G L, FENG Z J, ZHENG Q C, et al. Molecular dynamics simulation of nano-polishing of single crystal silicon on non-continuous surface [J]. Materials Science in Semiconductor Processing,2020(118):105168. [14] WANG Y Q, GUO J. Effect of abrasive size on nano abrasive machining for wurtzite GaN single crystal via molecular dynamics study [J]. Materials Science in Semiconductor Processing,2021(121):105439. [15] TIAN Z G, CHEN X, XU X P. Molecular dynamics simulation of the material removal in the scratching of 4H-SiC and 6H-SiC substrates [J]. International Journal of Extreme Manufacturing,2020,2(4):45104. doi: 10.1088/2631-7990/abc26c [16] LIN W Q, HU Z W, CHEN Y, et al. Comparison of Vibration-Assisted Scratch Characteristics of SiC Polytypes (3C-, 4H-and 6H-SiC) [J]. Micromachines,2022,13(4):640. doi: 10.3390/mi13040640 [17] CHEN Z H, LUO Q F, LU J, et al. Understanding the Mechanisms of SiC-Water Reaction during Nanoscale Scratching without Chemical Reagents [J]. Micromachines,2022,13(6):930. doi: 10.3390/mi13060930 [18] WU Z H, ZHANG L C, YANG S Y. Effect of abrasive grain position patterns on the deformation of 6H-silicon carbide subjected to nano-grinding [J]. International Journal of Mechanical Sciences,2021(211):106779. [19] 史若彤, 邓子龙, 高兴军, 等. 基于Deform-3D的镍基高温合金残余应力仿真分析 [J]. 辽宁石油化工大学学报,2017,37(4):49-52. doi: 10.3969/j.issn.1672-6952.2017.04.011SHI Ruotong, DENG Zilong, GAO Xingjun, et al. Simulation study on residual stress of nickel-based superalloys based on deform-3D [J]. Journal of Liaoning shihua university,2017,37(4):49-52. doi: 10.3969/j.issn.1672-6952.2017.04.011