论文标题
溶解驱动应力腐蚀破裂的相位场配方
A phase field formulation for dissolution-driven stress corrosion cracking
论文作者
论文摘要
我们提出了一个新的理论和数值框架，用于建模弹性塑料固体中的机械辅助腐蚀。可以捕获点蚀和应力腐蚀破裂（SCC），以及坑对裂缝的过渡。假定局部腐蚀是溶解驱动的，并且提出了基于膜破裂 - 解散 - 重新激活机制的配方，以结合膜钝化的影响。该模型首次结合了机械过力作为电化学驱动力的作用，加速了腐蚀动力学。通过使用相位场范式来解决与跟踪不断发展的金属电解质界面相关的计算复杂性，从而可以准确地近似复杂的SCC形态。使用有限元方法和隐式时间集成方案在数值上实现了耦合的电化学配方。位移，相位阶参数和浓度是主要变量。讨论了五个特别感兴趣的案例研究，以展示该模型的预测能力，揭示了与分析解决方案和实验测量的极好一致性。 By modelling these paradigmatic 2D and 3D boundary value problems we show that our formulation can capture: (i) the transition from activation-controlled corrosion to diffusion-controlled corrosion, (ii) the sensitivity of interface kinetics to mechanical stresses and strains, (iii) the role of film passivation in reducing corrosion rates, and (iv) the dependence of the stability of the passive film to local应变率。这些因素在推动SCC缺陷的形状变化（包括凹痕过渡）的形状变化方面的影响是模型的自然结果，为工程材料和结构的机械评估奠定了基础。
We present a new theoretical and numerical framework for modelling mechanically-assisted corrosion in elastic-plastic solids. Both pitting and stress corrosion cracking (SCC) can be captured, as well as the pit-to-crack transition. Localised corrosion is assumed to be dissolution-driven and a formulation grounded upon the film rupture-dissolution-repassivation mechanism is presented to incorporate the influence of film passivation. The model incorporates, for the first time, the role of mechanical straining as the electrochemical driving force, accelerating corrosion kinetics. The computational complexities associated with tracking the evolving metal-electrolyte interface are resolved by making use of a phase field paradigm, enabling an accurate approximation of complex SCC morphologies. The coupled electro-chemo-mechanical formulation is numerically implemented using the finite element method and an implicit time integration scheme; displacements, phase field order parameter and concentration are the primary variables. Five case studies of particular interest are addressed to showcase the predictive capabilities of the model, revealing an excellent agreement with analytical solutions and experimental measurements. By modelling these paradigmatic 2D and 3D boundary value problems we show that our formulation can capture: (i) the transition from activation-controlled corrosion to diffusion-controlled corrosion, (ii) the sensitivity of interface kinetics to mechanical stresses and strains, (iii) the role of film passivation in reducing corrosion rates, and (iv) the dependence of the stability of the passive film to local strain rates. The influence of these factors in driving the shape change of SCC defects, including the pit-to-crack transition, is a natural outcome of the model, laying the foundations for a mechanistic assessment of engineering materials and structures.
