Understanding of years-old multifaceted hydrogen-assisted damage evolution necessitates efforts to model the coupled diffusion-mechanics response in metallic materials. Informed by the dislocation-hydrogen interactions, understood earlier via experiments and/or multi-scale modeling techniques, this work presents a dislocation density-based crystal plasticity model coupled with a hydrogen diffusion/trapping model to simulate the hydrogen-assisted deformation and failure under the HELP mechanism of hydrogen embrittlement. The important role of hydrogen on dislocation multiplication, annihilation and dislocation interaction weakening are included in the presented framework. Two possible scenarios under HELP mechanism, leading to H-induced macroscopic softening or hardening as a result of trade-off between the hydrogen-induced weakening of dislocation interactions and hydrogen-induced increased dislocation density emerges from the simulation studies. These finding points towards the inevitable role of HELP mechanism to cause early failure in metals either working independently or in support with additional mechanisms.

了解多年多面的氢辅助损伤演化需要努力模拟金属材料中的耦合扩散力学响应。受位错-氢相互作用的启发，通过实验和/或多尺度建模技术更早地了解，这项工作提出了一个基于位错密度的晶体塑性模型与氢扩散/俘获模型相结合，以模拟氢辅助变形和失效氢脆的HELP机制。氢对位错增殖、湮灭和位错相互作用减弱的重要作用包含在所提出的框架中。HELP机制下的两种可能场景，由于氢引起的位错相互作用减弱和氢引起的位错密度增加之间的权衡，导致氢引起的宏观软化或硬化从模拟研究中出现。这些发现表明 HELP 机制不可避免地会导致金属早期失效，无论是独立工作还是支持其他机制。