Nano-scale simulation of directional solidification in TWIP stainless steels: A focus on plastic deformation mechanisms

In this study, in order to understand the nanostructure of FeCrNi steels laser powder bed fusion (LPBF) process, directional solidification was simulated using large-scale molecular dynamics simulation (LSMDS). For purpose an atomic box with a dimension 70×40×60(nm3) including random dispersion Fe, Cr and Ni created. Then, two different fixed temperatures were considered for left right side during cooling from liquid molten state. evaluation uniformity mechanical properties, uniaxial tensile tests performed parallel perpendicular directions. Extensive twinning induced plasticity (TWIP) occurred along Shockley partial dislocations (DLs) evolution both directions, while ultimate strengths (UTS) obtained as sign non-uniform behavior. Different plastic deformation mechanisms at nano-scale stacking faults (SFs) interaction each other/grain boundaries (GBs)/twin (TBs), formation defective coherent twins (DCTs), dynamic Hall-Petch, shear stress gradient (back stress), new mechanism recrystallization room temperature are discussed detail.