Investigation of the recovery and annealing kinetics of deformed?-iron by magnetic measurements

Sensitivity of Conventional and Non-destructive Characterization Techniques to Recovery and Recrystallization

“…Quantification of dislocation densities in materials can be achieved through transmission electron microscopy (TEM). However, as heavily cold rolled steels develop a highly complex substructure, such evaluation cannot be accurately achieved and TEM is replaced by indirect methods like magnetic techniques, [1][2][3] X-ray line broadening, 4) X-ray peak resolution, 5) tensile stress 6,7) or Vickers hardness measurements. 8,9) Among these techniques, magnetic measurements have the advantage of being non-destructive in nature.…”

“…As theoretical considerations demonstrate that the coercive field, H c , is proportional to the square root of the dislocation density, r this parameter has been the most used among several magnetic parameters to monitor recovery in different materials. [1][2][3][11][12][13] During recovery, the grain structure remains constant and microstructural changes only occur in the cold rolling dislocation substructure inside the grains. The reduction in the dislocation density during recovery decreases the density of pinning sites for the motion of magnetic domain walls in the matrix, which is normally reflected as a decrease in H c values from the cold rolled state.…”

“…The reduction in the dislocation density during recovery decreases the density of pinning sites for the motion of magnetic domain walls in the matrix, which is normally reflected as a decrease in H c values from the cold rolled state. [1][2][3][11][12][13] As a fast, although minimally invasive technique, hardness measurements have been shown not to have enough sensitivity to characterize the recovery processes in a heavily cold rolled low carbon steel 3) and in an interstitial free (IF) steel to have small resolution at temperatures slightly below the onset of recrystallization, but to be absolutely insensitive at lower temperatures. 12) Recrystallization produces microstructure regeneration through the nucleation of substructure free volumes and by the recrystallization front migration through the material which results in a new grain microstructure producing the mechanical 14) and magnetic softening of steel.…”

COMPARISON STUDY BEWTWEEN THE RECOVERY BEHAVIOR OF DEFORMED QUENCHED, PRE-ANNEALED AND PULSED LASER DAMAGED Fe50Ni50 ALLOY BY MAGNETIC MEASUREMENTS

“…The material was shaped by extrusion into rods of 3mm diameter followed by swaging at room temperature to wires of 1mm diameter. The atomic absorption method was used in order to determine the composition of the alloy (Table 1) [21]. The wire sample was introduced as a core of a magnetization coil and the cathode ray technique was employed to obtain room-temperature B-H curves at different magnetizing fields.…”

Sensitiveness of Magnetic Inductive Parameters for the Characterization of Recovery and Recrystallization in Cold-Rolled Low-Carbon Steel

“…[5] The reduction of B r has been attributed to the increase in individual pinning site energies as dislocation tangles form very effective barriers that strongly hinder the movement of domain walls; [2] therefore, the coercive field [2][3][4] and hysteresis losses [3] increase. The annealing of plastically deformed electrical steels [3,6] and of iron [7] has received less attention in the literature. In general terms, annealing tends to turn back the magnetic properties of the material previous to deformation, which has also been attributed to the elimination of macroscopic residual stresses.…”