Reinforced concrete is one of the most critical composite materials in the modern civil engineering and can improve the tensile resistance of concrete. Its passivation film plays an important role in the durability of concrete and the steel corrosion. But, due to the size limitations, the destruction of micro-scale steel bars has not been well studied. In this work, the reactive molecular dynamics simulation was employed to studying the mechanical properties of the steel and its passivation film. The uniaxial stretching of different compounds of γ-FeOOH, γ-Fe₂O₃ and Fe was performed. We found that the oxidation can reduce the tensile strength of steel. For the three compounds of γ-FeOOH, γ-Fe₂O₃ and Fe, the order of tensile strength from high to low is Fe > γ-Fe₂O₃ > γ-FeOOH. But, the ductility of γ-FeOOH under x direction is increased. The detail microstructure analysis shown that the difference of tensile strength is origin from the coordination in the materials. The two kinds of stretching processes of whole system stretching (in the Fe phase and x direction of γ-FeOOH phase) and partly area stretching (in the Fe₂O₃ phase and z direction of γ-FeOOH phase) were clarified. The external force is dispersed in whole system stretching but opposite in partly area stretching. This investigation leads to possible new direction for studying the tensile strength of materials, and the strategy of evaluating materials tensile strength can supply valuable information in evaluating and improving the mechanical properties of reinforced concrete.

钢筋混凝土是现代土木工程中最关键的复合材料之一，可以提高混凝土的抗拉强度。它的钝化膜在混凝土的耐久性和钢的腐蚀中起着重要的作用。但是，由于尺寸的限制，对微米级钢筋的破坏还没有很好的研究。在这项工作中，反应性分子动力学模拟被用来研究钢及其钝化膜的力学性能。单轴拉伸γ-的FeOOH，γ-的Fe不同化合物的₂ ö ₃进行和Fe。我们发现，氧化会降低钢的拉伸强度。对于γ-的FeOOH，γ-Fe的三种化合物₂ ö ₃和Fe，拉伸强度的顺序从高到低的为Fe>了γ-Fe ₂ ö ₃ >γ-的FeOOH。但是，γ-FeOOH的延展性在X方向增加。详细的微观结构分析表明，拉伸强度的差异是由材料中的配位引起的。整个系统拉伸的两种拉伸过程（在Fe相和Xγ-FeOOH相的方向）和部分区域拉伸（在Fe ₂ O ₃相和ž明确了γ-FeOOH相的方向）。外力在整个系统拉伸中分散，而在部分区域拉伸中相反。这项研究为研究材料的抗张强度提供了可能的新方向，而材料抗张强度的评估策略可以为评估和改善钢筋混凝土的力学性能提供有价值的信息。