Computational modelling of cold rolling of ferritic iron containing ε-Cu precipitates

The precipitation strengthening of ferritic iron using copper particles was studied using a molecular dynamics model. The developed model simulated the cold rolling of a ferrite sample containing copper precipitates at three different thickness reductions. The dislocation density and the amorphous structure in the ferrite sample increased as the thickness reduction increased. The copper particles experienced severe elongation, and their aspect ratios increased as the thickness reduction increased. It was found that the copper particles lose the fcc structure and transform to amorphous and bcc structures. As the thickness reduction increases, a fraction of the atoms changing to the bcc structure dissolved into the ferrite matrix. The remaining bcc structure atoms were at the interface between the copper particles and the ferrite matrix. Tensile testing of the deformed samples confirmed that the copper particles strengthened the ferrite for up to 30 % thickness reduction, while above 30 % resulted in lower strength due to copper particles’ dissolution.