因瓦合金纳米抛光材料去除机理的分子动力学模拟?

因瓦合金作为一种独特的低膨胀材料已广泛用于航空航天等高科技领域,但目前还鲜有对其超精密加工理论和技术的研究,而纳米抛光是因瓦合金超精密加工的一种重要手段。 针对纳米抛光过程中因瓦合金的材料去除机理,基于分子动力学模拟研究抛光速度对材料去除效率、亚表面损伤和抛光表面平整度的影响。 通过对磨屑、能量、抛光力、位错运动等方面的分析揭示因瓦合金的变形损伤机制。 研究结果表明:材料去除效率随着抛光速度将达到一个临界值,当抛光速度低于 100 m/ s 时,磨削热促使位错形核,亚表面损伤厚度增加;当抛光速度高于 100 m/ s 时,应变速率急剧增大导致位错运动受限,使得亚表面损伤厚度得以降低。 为实现因瓦合金高效率和低损伤加工机制提供理论依据和技术支持。

Molecular Dynamics Simulation on the Material Removal Mechanism in the Nano-polishing Process of Invar Alloy

As a unique kind of low-expansion materials, Invar alloy has been widely used in high-tech fields, such as aerospace, but few studies are conducted on its ultra-precision machining theory and technology. Among them, nano-polishing is an important method for ultra-precision machining of Invar alloy. Aiming at showing the material removal mechanism of Invar alloy in the nano-polishing process, the influence of polishing speed on the material removal rate, subsurface damage and the smoothness of polished surface is studied based on molecular dynamics simulation. Specifically, through the analysis of polishing chip, energy, polishing force and dislocation movement, the deformation and damage mechanism of Invar alloy is revealed. It is shown that the material removal rate will reach a critical value as the polishing speed increases. When the velocity increases, the grinding heat promots nucleation of dislocations, and therefore the subsurface damage thickness increases. However, with the velocity over than 100 m/ s, the drastically increased strain rate leads to the limitation of dislocation movement, which reduces the thickness of subsurface damage. This paper enriches the theoretical understanding and provides technological references for realizing the high efficiency and low damage machining mechanism of Invar alloy.