Physical constitutive relational model and structure evolution during dynamic recovery of 23Co14Ni12Cr3MoE (A-100) high-strength steel

The hot compression of A-100 steel at 850-1150 degrees C and strain rate of 0.01-10 s(-1) was tested on a Gleeble-3800 thermal simulation machine to determine the corresponding true stress-strain curve. Based on theoretical calculation, the dislocation density factor was introduced into the Avrami equation and thereby a dynamic recovery physical constitutive relational model based on dislocation density theory was established. Then the hot deformation behaviour of A-100 steel was predicted (correlation coefficient R = 0.9964 with an average absolute relative error AARE = 4.0923%). The structures after hot compression were observed by electron backscattered diffraction and found to be lath-shaped martensite and austenite. With an increase of temperature and deceleration of strain rate, the proportions of large-angle boundaries and substructures increased and the softening mechanism became dominated by dynamic recovery.