Evolution of dislocation structures and deformation behavior of iron at different temperatures: Part II. dislocation density and theoretical analysis

Abstract

The evolution of dislocation density in iron deformed at 173 K and at room temperature has been examined by transmission electron microscopy (TEM). At room temperature, the dislocation density in the cell walls increases as the deformation progresses up to large strains, whereas in cell interiors, the density evolves toward a saturation value. A linear relationship exists between the flow stress and the square root of total dislocation density both at 173 K and room temperature. The dependence of deformation behavior on the evolution of dislocation structures is discussed in terms of a model considering the dislocation distribution during deformation. Comparison of the calculated result using this model with the experimental curve at room temperature gives excellent agreement. The changes of deformation behaviors at different temperatures can be described by the effect of temperature on the evolution of dislocation distribution.