{"title":"切削工具几何形状对梯度纳米晶粒钴铬镍中熵合金材料切削的影响","authors":"Yu-Sheng Lu, Yu-Xuan Hung, Thi-Xuyen Bui, Te-Hua Fang","doi":"10.3762/bjnano.15.76","DOIUrl":null,"url":null,"abstract":"<p><p>CoCrNi medium-entropy alloys (MEAs) have attracted extensive attention and research because of their superior mechanical properties, such as higher ductility, strength, and toughness. This study uses molecular dynamics (MD) simulations to investigate the cutting behavior of a gradient nanograined (GNG) CoCrNi MEA. Moreover, it explores the influence of relative tool sharpness and rake angle on the cutting process. The results show that an increase in the average grain size of the GNG samples leads to a decrease in the average resultant cutting force, as predicted by the Hall-Petch relationship. The deformation behavior shows that grain boundaries are crucial in inhibiting the propagation of strain and stress. As the average grain size of the GNG sample increases, the range of shear strain distribution and average von Mises stress decreases. Moreover, the cutting chips become thinner and longer. The subsurface damage is limited to a shallow layer at the surface. Since thermal energy is generated in the high grain boundary density, the temperature of the contact zone between the substrate and the cutting tool increases as the GNG size decreases. The cutting chips removed from the GNG CoCrNi MEA substrates will transform into a mixed structure of face-centered cubic and hexagonally close-packed phases. The sliding and twisting of grain boundaries and the merging of grains are essential mechanisms for polycrystalline deformation. Regarding the cutting parameters, the average resultant force, the material accumulation, and the chip volume increase significantly with the increase in cutting depth. In contrast to sharp tools, which mainly use shear deformation, blunt tools remove material by plowing, and the cutting force increases with the increase in cutting-edge radius and negative rake angle.</p>","PeriodicalId":8802,"journal":{"name":"Beilstein Journal of Nanotechnology","volume":null,"pages":null},"PeriodicalIF":2.6000,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11285073/pdf/","citationCount":"0","resultStr":"{\"title\":\"Effects of cutting tool geometry on material removal of a gradient nanograined CoCrNi medium entropy alloy.\",\"authors\":\"Yu-Sheng Lu, Yu-Xuan Hung, Thi-Xuyen Bui, Te-Hua Fang\",\"doi\":\"10.3762/bjnano.15.76\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>CoCrNi medium-entropy alloys (MEAs) have attracted extensive attention and research because of their superior mechanical properties, such as higher ductility, strength, and toughness. This study uses molecular dynamics (MD) simulations to investigate the cutting behavior of a gradient nanograined (GNG) CoCrNi MEA. Moreover, it explores the influence of relative tool sharpness and rake angle on the cutting process. The results show that an increase in the average grain size of the GNG samples leads to a decrease in the average resultant cutting force, as predicted by the Hall-Petch relationship. The deformation behavior shows that grain boundaries are crucial in inhibiting the propagation of strain and stress. As the average grain size of the GNG sample increases, the range of shear strain distribution and average von Mises stress decreases. Moreover, the cutting chips become thinner and longer. The subsurface damage is limited to a shallow layer at the surface. Since thermal energy is generated in the high grain boundary density, the temperature of the contact zone between the substrate and the cutting tool increases as the GNG size decreases. The cutting chips removed from the GNG CoCrNi MEA substrates will transform into a mixed structure of face-centered cubic and hexagonally close-packed phases. The sliding and twisting of grain boundaries and the merging of grains are essential mechanisms for polycrystalline deformation. Regarding the cutting parameters, the average resultant force, the material accumulation, and the chip volume increase significantly with the increase in cutting depth. 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引用次数: 0
摘要
钴铬镍中熵合金(MEA)具有更高的延展性、强度和韧性等优异的机械性能,因此受到了广泛的关注和研究。本研究采用分子动力学 (MD) 模拟来研究梯度纳米晶粒 (GNG) CoCrNi MEA 的切削行为。此外,研究还探讨了相对刀具锋利度和前角对切削过程的影响。结果表明,正如霍尔-佩奇关系所预测的那样,GNG 样品的平均晶粒尺寸增大会导致平均切削力减小。变形行为表明,晶界对抑制应变和应力的传播至关重要。随着 GNG 样品平均晶粒尺寸的增大,剪切应变分布范围和平均 von Mises 应力也随之减小。此外,切屑变得更薄、更长。次表层损伤仅限于表面的浅层。由于热能是在高晶界密度中产生的,因此随着 GNG 尺寸的减小,基体和切削工具接触区的温度也会升高。从 GNG CoCrNi MEA 基体上取出的切屑将转变为面心立方相和六方紧密堆积相的混合结构。晶界的滑动和扭曲以及晶粒的合并是多晶变形的基本机制。在切削参数方面,随着切削深度的增加,平均结果力、材料累积量和切屑量都会显著增加。与主要利用剪切变形的锋利刀具相比,钝刀通过犁耕去除材料,切削力随刀刃半径和负前角的增加而增加。
Effects of cutting tool geometry on material removal of a gradient nanograined CoCrNi medium entropy alloy.
CoCrNi medium-entropy alloys (MEAs) have attracted extensive attention and research because of their superior mechanical properties, such as higher ductility, strength, and toughness. This study uses molecular dynamics (MD) simulations to investigate the cutting behavior of a gradient nanograined (GNG) CoCrNi MEA. Moreover, it explores the influence of relative tool sharpness and rake angle on the cutting process. The results show that an increase in the average grain size of the GNG samples leads to a decrease in the average resultant cutting force, as predicted by the Hall-Petch relationship. The deformation behavior shows that grain boundaries are crucial in inhibiting the propagation of strain and stress. As the average grain size of the GNG sample increases, the range of shear strain distribution and average von Mises stress decreases. Moreover, the cutting chips become thinner and longer. The subsurface damage is limited to a shallow layer at the surface. Since thermal energy is generated in the high grain boundary density, the temperature of the contact zone between the substrate and the cutting tool increases as the GNG size decreases. The cutting chips removed from the GNG CoCrNi MEA substrates will transform into a mixed structure of face-centered cubic and hexagonally close-packed phases. The sliding and twisting of grain boundaries and the merging of grains are essential mechanisms for polycrystalline deformation. Regarding the cutting parameters, the average resultant force, the material accumulation, and the chip volume increase significantly with the increase in cutting depth. In contrast to sharp tools, which mainly use shear deformation, blunt tools remove material by plowing, and the cutting force increases with the increase in cutting-edge radius and negative rake angle.
期刊介绍:
The Beilstein Journal of Nanotechnology is an international, peer-reviewed, Open Access journal. It provides a unique platform for rapid publication without any charges (free for author and reader) – Platinum Open Access. The content is freely accessible 365 days a year to any user worldwide. Articles are available online immediately upon publication and are publicly archived in all major repositories. In addition, it provides a platform for publishing thematic issues (theme-based collections of articles) on topical issues in nanoscience and nanotechnology.
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