Yu Dongling, Zhang Huiling, Feng Xiaoyu, Liao Dahai, Wu Nanxing
School of Mechanical and Electronic Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333403, Jiangxi, China.
Laboratory of Ceramic Material Processing Technology Engineering, Jingdezhen 333403, Jiangxi, China.
ACS Omega. 2022 May 16;7(21):18168-18178. doi: 10.1021/acsomega.2c02115. eCollection 2022 May 31.
To investigate the subsurface damage of 6H-SiC nanofriction, this paper uses molecular dynamics analysis to analyze the loading process of friction 6H-SiC surfaces, thus providing an in-depth analysis of the formation mechanism of subsurface damage from microscopic crystal structure deformation characteristics. This paper constructs a diamond friction 6H-SiC nanomodel, combining the radial distribution function, dislocation extraction method, and diamond identification method with experimental analysis to verify the dislocation evolution process, stress distribution, and crack extension to investigate the subsurface damage mechanism. During the friction process, the kinetic and potential energies as well as the temperature of the 6H-SiC workpiece basically tend to rise, accompanied by the generation of dislocated lumps and cracks on the sides of the 6H-SiC workpiece. The stresses generated by friction during the plastic deformation phase lead to dislocations in the vicinity of the diamond tip friction, and the process of dislocation nucleation expansion is accompanied by energy exchange. Dislocation formation is found to be the basis for crack generation, and cracks and peeled blocks constitute the subsurface damage of 6H-SiC workpieces by diamond identification methods. Friction experiments validate microscopic crystal changes against macroscopic crack generation, which complements the analysis of the damage mechanism of the simulated 6H-sic nanofriction subsurface.
为研究6H-SiC纳米摩擦的亚表面损伤，本文采用分子动力学分析方法对6H-SiC表面的摩擦加载过程进行分析，从而从微观晶体结构变形特征深入分析亚表面损伤的形成机制。本文构建了金刚石摩擦6H-SiC纳米模型，将径向分布函数、位错提取方法和金刚石识别方法与实验分析相结合，以验证位错演化过程、应力分布和裂纹扩展，从而研究亚表面损伤机制。在摩擦过程中，6H-SiC工件的动能、势能以及温度基本呈上升趋势，同时在6H-SiC工件侧面会产生位错团块和裂纹。塑性变形阶段摩擦产生的应力导致金刚石尖端摩擦附近产生位错，位错形核扩展过程伴随着能量交换。发现位错形成是裂纹产生的基础，通过金刚石识别方法可知，裂纹和剥落块构成了6H-SiC工件的亚表面损伤。摩擦实验验证了微观晶体变化与宏观裂纹产生之间的关系，这补充了对模拟6H-SiC纳米摩擦亚表面损伤机制的分析。
