Experimental Investigation and Numerical Simulation of theCorrelation of Recovery and Texture in Bcc Metals and Alloys

Abstract

Depending on the strain and temperature regime examined recovery of bcc metals during hot rolling or annealing subsequent to cold deformation often leads to the preservation of certain deformation texture components. A broad variety of mesoscopic and macroscopic texture data from both hot rolled and cold rolled and annealed bcc metals (Fe, Ta, Mo, Nb) and alloys (low‐carbon steels, ferritic stainless steels, transformer steels) is re‐examined with respect to such phenomena. The data suggest that two conditions promote strong recovery of certain bcc deformation texture components (e.g. {001} <110>), namely, the absence of kinetic instabilities, and the absence of thermodynamic and mechanic instabilities. The first case applies if the grains do not tend to generate large local misorientations in their interiors during plastic deformation. The second case applies if the stored dislocation density is low. Both features depend on the grain orientation. The experimental observations are complemented by three types of numerical simulations. The influence of the number of Burgers vectors equally involved during preceding deformation on the kinetics of static recovery is numerically studied using 2 dimensional dislocation dynamics. The orientation dependent inclination to generate local misorientations in the grain interiors is simulated using a Taylor type approach with different constraints on either side of the grain. The influence of the orientation dependence of recovery on the final annealing texture is simulated using a 3 dimensional cellular automation. Experiment and simulation show that both the recovery kinetics and the tendency to form kinetic instabilities considerably depend on the orientation. The latter effect seems to be essential for the prevalence of either RX or RC.