Molecular Dynamics Study: Effects of He Bubble and Cr Precipitate on Tensile Deformation of Grain Boundaries in $\alpha$ -Fe

To investigate irradiation-induced embrittlement in ferritic/martensitic (F/M) steels, molecular dynamics are applied to simulate tensile deformation of grain boundaries (GBs) under the effects of helium bubbles and Cr precipitates in pure α-Fe. Strength and elongation of symmetric tilt GBs with <;110> and <;100> tilt axis at 300 K are calculated to investigate the effects of helium-vacancy (He-V) cluster sizes and helium/vacancy (He/V) ratios in clusters. The results show that He-V clusters have notable suppression on GB plastic deformation. The size effect of He-V clusters on GB gliding seems to be stronger than that of He-V ratio. It is interested that the suppression of Cr precipitates is much weaker than He-V clusters. Visualization analyses show that the plasticity of GB is induced by GB glide and the He-V clusters have significant suppression on its glide.