Mechanical behavior of Fe₈₀P₂₀/α-Fe amorphous/nanocrystalline composites studied by molecular dynamics simulations

In this paper, the compression mechanical behavior of Fe₈₀P₂₀/α-Fe amorphous /nanocrystalline composites (ANCCs) with grain diameters (d) from 0 to 6 nm was studied by molecular dynamics simulations. The peak strength (τ_p) increases with increasing d from 0 to 6 nm, while the flow strength (τ_s) increases with increasing d from 0 to 5 nm, then decreases with further increasing d to 6 nm. As a result, the composite with d = 5 nm exhibits the highest normalized difference (Δτ/τ_p, where Δτ = τ_p – τ_s) indicating its good plasticity. In order to reveal the effect mechanism of nanocrystalline size on deformation behavior, the atomic shear strain at different levels was analyzed. Besides, the amorphization of α-Fe phase during deformation was investigated by common neighbor analysis. The result is helpful for improving the mechanical properties of Fe-based ANCCs by strict controlling of heat treatment process to adjust the nanocrystalline size.