金属腐蚀的多尺度计算模拟研究进展

Progress in Multi-Scale Calculation and Simulation of Metal Corrosion

综述了计算方法在金属腐蚀研究中的应用与进展,提出了利用第一性原理与内聚有限单元相结合的跨尺度计算与模拟方法研究金属铝的腐蚀行为与机理。采用基于密度泛函的第一性原理计算Cl-与钝化膜的相互作用,明确了铝点蚀的萌生机理。利用第一性原理计算方法研究Al-H体系,计算了H原子沿铝表面以及从表面向内部的吸附、溶解和扩散,表明H沿晶界的扩散和偏聚对晶界强度影响显著。将第一性原理计算得到的晶界结合能输入到内聚有限元模型,模拟铝合金的晶间开裂行为,实现了原子尺度到宏观尺度的衔接,建立了从原子尺度到宏观尺度的跨尺度计算与模拟框架。

The application and progress of calculation and simulation in the field of metal corrosion are summarized in this paper,which provide a cross-scale method combined with first-principles and finite element calculation to investigate the behavior and mechanism of Al and its alloys.We have carried out the calculations of the adsorption of O 2 and H 2 O on Al surface to study the forming mechanism of passive film.The pitting initiation was studied by the interaction between Cl-and passive film using first-principles calculations,which was proved that the pitting initiation tended to Cl-adsorption induced oxide thinning.The adsorption,solution and diffusion of H atom was performed along Al(111)surface to obtain the most stable adsorption and solution site and the diffusion energy barrier.A grain boundary(GB)and grain models were constructed to characterize the solution and diffusion of H atom.The strength of GB characterized by its cohesive energy was calculated by first-principles method,which decreased with the increasing H concentration segregated in GB.The cohesive energies were input into cohesive finite element calculations as the fracture energies to simulate the intergranular cracking,which was a cross-scale study.The application of the cross-scale approach is very efficient for investigating the evolution of hydrogen induced intergranular cracking.The work of this study provides a scheme using a cross-scale calculation from atomic scale to macro-scale to study the atmospheric corrosion behavior and mechanism of metals.