Hydrogen effects on nanovoid nucleation in face-centered cubic single-crystals

Monte Carlo (MC) and molecular dynamics (MD) simulations using embedded atom method (EAM) potentials were performed to study nanovoid nucleation in single-crystal nickel specimens in a hydrogen-precharged and a hydrogen dynamically-charged condition. In the hydrogen-precharged condition, MC simulations were performed to introduce hydrogen atoms in an unstressed specimen. MD simulations were then performed to study nanovoid nucleation and the associated plasticity. In the dynamically-charged condition, a novel coupled MD-MC process was used to introduce hydrogen into the specimen while the specimen was being strained until nanovoid nucleation occurred. The simulation results revealed that hydrogen only reduced the nanovoid nucleation stress in the precharged case slightly but caused a lower strain-hardening and a significant reduction in the nanovoid nucleation stress in the dynamically-charged case.