MD simulations of strengthening by graphene in iron crystals

铁晶体中石墨烯强化的 MD 模拟

• 批准号: 427509047
• 负责人: Professor Dr. Johannes Roth, since 4/2023
• 金额: --
• 依托单位: Institut für Funktionelle Materie und Quantentechnologien
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/427509047?language=en
• 关键词: MD; simulations; strengthening; graphene; iron

In iron alloys, the increase in strength caused by solid solution, precipitate and grainboundary strengthening, plays an outstanding role in the technical application of the materials. In this project, the influence of nanoscale graphene discs embedded into the iron matrix and of carbon in solid solution on the mechanical properties, respectively, is investigated by means of ab initio and molecular dynamics (MD) simulations. The addition of graphene disks is expected to improve several mechanical properties. In particular, the thermal stability of the graphene discs and the properties of elasticity, strength and plasticity of the iron/graphene composite material are of importance. To estimate the thermal stability of the graphene discs, ab initio simulations are performed, which are also used to improve the interatomic potentials for the MD simulations. Molecular dynamics simulations using single- and polycrystals will be performed for different temperatures, carbon and graphene concentrations, as well as for different sizes, distances and orientations of the graphene discs.The objectives of the simulations are fundamental findings concerning dislocation/precipitate interactions, stress fields and residual stresses in the crystal lattice caused by the graphene discs or alloyed carbon atoms, and the associated changes in the mechanical properties of these materials.For the first time, MD simulations are used to investigate whether and to which extent the properties of iron can be improved by the addition of graphene discs in the desired direction of maximum strength with maximum elasticity and best possible plastic deformability (ductility and fracture strain) respectively.

在铁合金中，固溶、析出和晶界强化引起的强度增加，在材料的技术应用中发挥着突出的作用。在该项目中，通过从头算和分子动力学（MD）模拟的方式分别研究了嵌入铁基体中的纳米级石墨烯盘和固溶体中的碳对机械性能的影响。石墨烯盘的添加预计将改善多种机械性能。特别是，石墨烯盘的热稳定性以及铁/石墨烯复合材料的弹性、强度和塑性性能非常重要。为了估计石墨烯圆盘的热稳定性，进行了从头算（ab initio）模拟，这也用于提高 MD 模拟的原子间势。使用单晶和多晶的分子动力学模拟将针对不同的温度、碳和石墨烯浓度以及石墨烯盘的不同尺寸、距离和方向进行。模拟的目标是关于位错/沉淀相互作用、应力的基本发现石墨烯盘或合金碳原子引起的晶格中的场和残余应力，以及这些材料机械性能的相关变化。MD模拟首次用于研究是否以及通过在最大强度、最大弹性和最佳塑性变形能力（延展性和断裂应变）所需的方向上添加石墨烯盘，可以在一定程度上改善铁的性能。