基于分子动力学模拟FeO/Fe界面断裂过程

FeO/Fe interface fracture process based on molecular dynamics simulation

氧化皮与钢基体的粘结特性决定了环保型无酸除鳞的工艺参数设定精度。为了分析低碳钢基体与表面氧化皮的脱粘规律,采用分子动力学软件模拟了FeO/Fe构成的分析对象在拉伸载荷作用下界面裂纹的扩展行为,分析了裂纹恒定阶段和裂纹扩展阶段的局部正应力分布和位移变化;并利用裂纹稳态扩展条件下的局部正应力和位移数据拟合了牵引分离曲线图,同时与指数型、双线型以及三次多项式型粘聚力模型等3种模型进行了比较,偏差平方和分别为245.86、222.02、406.10。结果表明该方法可以快速准确预测FeO与Fe的脱粘规律,对揭示氧化皮与钢基体的脱粘规律以及无酸除鳞的技术推广提供了一定帮助。

The bonding characteristics between oxide scale and steel substrate determine the setting accuracy of process parameters for environmental friendly acid free descaling. In order to analyze the mechanism of debonding between the low carbon steel matrix and the surface oxide scale, FeO/Fe was taken as the research object, and molecular dynamics software was used to simulate the growth behavior of the interface cracks of the FeO/Fe under tensile load. The local normal stress distribution and displacement at constant stage and propagation stage of crack and were analyzed. The local normal stress and displacement under the condition of steady-state crack growth were used to fit the traction separation curve, and compared with the exponential, bilinear and cubic polynomial cohesion models, and the sum of squared deviations was 245.86, 222.02, and 406.10, respectively. The results show that this method can predict the debonding mechanism of FeO and Fe quickly and accurately, which is helpful to reveal the debonding mechanism of oxide scales and steel matrix, as well as to promote the technology of acid free descaling.