Influence of oxide layers on plastic properties of metals: From atomistic to mesoscopic scale

由于在富氧化环境中，氧化物层将在金属表面上形成，因此需要考虑氧化对位错成核的影响。这对于具有高表面积与体积比的材料（如多孔物质）和轻质材料（如铝）尤其重要。对于后者，即使在高真空条件下，氧化物层也可以在几秒钟内形成。这将影响材料的机械性能，因为增加的位错成核，由于增加的激活体积和增加的位错位点的数量，导致纳米晶金属的延展性增强。氧化对金属机械性能的影响将使用分子动力学进行研究，因为在富含氧化物的环境中，考虑到氧浓度和温度的基本依赖性，氧化物层将在模拟中形成。本研究的重点将主要放在氧化金属的位错成核上。将分析从在介观尺度下观察到的开裂行为到在纳米尺度下观察到的辅助延性行为的转变。原子模拟将使用随机模型在薄膜的介观位错动力学中考虑氧化物层来实现位错成核。因此，一个物理上可靠的氧化表面的位错动力学模拟模型，将可在时间尺度上访问的实验。

Since in oxidation-rich environments an oxide layer will form on metallic surfaces, the influence of oxidation on dislocation nucleation needs to be considered. This is particularly important for materials with high surface-to-volume ratio as porous matter and lightweight materials as aluminum. For the latter, even under high vacuum conditions, an oxide layer may form within seconds. This will influence the mechanical properties of materials because of increased dislocation nucleation due to increased activation volume and increased number of dislocation sites leading to enhanced ductility of nanocrystalline metals. The influence of oxidation on the mechanical properties of metals will be studied using molecular dynamics Since in oxidation-rich environments an oxide layer will form onsimulations considering the fundamental dependencies on oxygen concentration and temperature. The focus of this study will be primarily on the nucleation of dislocations for oxidized metals. The transition from the cracking behavior observed at the mesoscale, to the assisted-ductility behavior observed at the nano-scale will be analyzed. The atomistic simulations will be used to implement dislocation nucleation considering oxide layers in mesoscale dislocation dynamics of thin films using a stochastic model. Therewith, a physically reliable model for dislocation dynamics simulations of oxidized surfaces will be available acting on time scales accessible to experiments.