Capturing Hydrogen Embrittlement Effects with Hydrogen Diffusion Simulation and Crystal Plasticity

Hydrogen is a promising clean energy source, but its safe storage is challenging, as hydrogen has severe embrittling effects on metals. The extent of hydrogen embrittlementHydrogen embrittlement depends on the local hydrogen concentrationHydrogen concentration and how it couples with the thermal and structural counterparts. This work presents a framework for hydrogen diffusion and embrittlement effects considering underlying microstructureMicrostructure. A hydrogen diffusion simulation is conducted on a microstructureMicrostructure with grain boundaryGrain boundaries trapping effect and trapping site saturation effect explicitly considered. The simulation provides a time history of hydrogen concentrationHydrogen concentration in the microstructureMicrostructure. The grain boundaryGrain boundaries decohesion and softening effects of hydrogen are described phenomenologically by a nonuniform initial slip resistance degradation, which is computed based on the hydrogen concentrationHydrogen concentration profile. This initial distribution is then used in crystal plasticity simulations to predict how the hydrogen exposure affects the mechanical propertiesMechanical properties such as initial yield stress and subsequent flow behavior. The results show that the diffusion model can capture the trapping effects of hydrogen as well as the gradual saturation of trapping sites with increased hydrogen concentrationHydrogen concentration. The phenomenological model for hydrogen-based slip resistance degradation is able to capture the increased softening with longer hydrogen exposure times. The current framework provides a simple yet effective framework to connect microstructure-informed diffusion simulation with crystal plasticity to quantitatively study hydrogenHydrogen embrittlement embrittlement.