Effect of bismuth on the mechanical properties and microstructure evolution of iron matrix during drawing: a molecular dynamics study

Abstract This paper investigates the effects of bismuth nanoparticles on the mechanical properties and microstructure evolution of single-crystal iron matrix materials during the drawing process using molecular dynamics methods, and also explores the effects of different drawing speeds and loading methods on the drawing process. The results show that the incorporation of bismuth nanoparticles has a significant effect on the axial drawing force, dislocation, shear strain and crystal evolution during the drawing process. When the bismuth nanoparticles started to deform under the action of drawing force, the atomic shear strain and crystal evolution were concentrated around them, which hindered the generation of dislocations and led to the reduction of their axial drawing force. In addition, the degree of atomic shear strain and crystal evolution increases with the increase of drawing speed, leading to work hardening of the material, and thus increasing the axial drawing force. Finally, when the loading mode is positioned at the rear end, shear strain becomes more concentrated around the bismuth nanoparticles, hindering dislocation generation and increasing the material’s hardness and axial drawing force. This study is important for understanding the mechanism of bismuth nanoparticles on the iron matrix of single-crystal during the drawing process.