Analysis of thermo-mechanical process occurred in magnesium alloy AZ31 sheet during differential speed rolling

Rolling is an effective method used to impose a large amount of plastic deformation to metallic materials in a form of sheet. As the plastic deformation increases at appropriate temperatures, the grains become smaller in size and the mechanical properties of the sheet are improved. A recent study found that the grains of magnesium alloy AZ31 sheets are recrystallized and reduced to 3 μm in diameter by a differential speed rolling at an elevated temperature. The present study analyzed the thermo-mechanical processes occurring in the sheet during differential speed rolling by the rigid-thermoviscoplastic finite element method. Findings include a significant increase of plastic deformation by severe shear deformation, a notable increase of temperature by plastic deformation as well as by friction, and an incredible decrease of rolling force by low hydrostatic stress in magnitude at the deformation zone.