Study on Work Hardening Mechanism of Hadfield Steel during Deformation Process

Abstract

Compression test of ZGMn13Cr2 Hadfield steel was carried out by Gleeble-3500 thermal simulator at the deformation temperature of 298 K under a constant loading strain rate of 0.1 s-1 and with the compressive deformation of 5%, 30%, and 50%, respectively. The effects of compressive deformations on the microstructure evolution and work hardening mechanism of ZGMn13Cr2 Hadfield steel were analyzed by optical microscope, vickers micro-hardness machine, transmission electron microscopy and X-ray diffraction. The test results show that a large number of deformation bands appeared in the grains of compressed high manganese steels. The deformation bands intersected, tangled and isolated with each other. A great deal of high density dislocation was entangled into dislocation cells or dislocation walls with the compression amount of 5%. Deformation twins appeared in the matrix when the compression amount was 30%. With the increasing of compressive deformation, the amount and volume fraction of the twins increased gradually. When the compression amount was 50%, the micro-hardness of water-quenched high manganese steel increased by 125% compared with the initial state, showing HV560.8. Meanwhile, XRD results show that the matrix structure remained austenite and with a bit of carbide, but no deformation-induced martensites were founded in these deformed samples. With the increasing of compressive deformation, work hardening mechanisms of Hadfield steel changed from dislocation strengthening into mainly relying on deformation twin supplemented by dislocation and stacking fault mechanisms.

Keywords: Hadfield steel,  work-hardening mechanism,  compression amounts,  microstructure,  properties