Nanoindentation study of cementite size and temperature effects in nanocomposite pearlite: A molecular dynamics simulation

• MD simulations of nanoindentation are performed on nanocomposite pearlites.
• Dislocations incoherently transmit from ferrite to cementite.
• Increasing temperature widens the distribution of plastic strain in ferrite.
• Hence, thickening cementite or increasing temperature enhances dislocation blocking.

We carry out molecular dynamics simulations of nanoindentation to investigate the effect of cementite size and temperature on the deformation behavior of nanocomposite pearlite composed of alternating ferrite and cementite layers. We find that, instead of the coherent transmission, dislocation propagates by forming a widespread plastic deformation in cementite layer. We also show that increasing temperature enhances the distribution of plastic strain in the ferrite layer, which reduces the stress acting on the cementite layer. Hence, thickening cementite layer or increasing temperature reduces the likelihood of dislocation propagation through the cementite layer. Our finding sheds a light on the mechanism of dislocation blocking by cementite layer in the pearlite.