Plastic deformation behaviors and hardening mechanism of M7C3 carbide

This paper reports an investigation of inelastic deformation behaviors of M7C3 carbide in high chromium cast iron by compression testing with a strain of 20% at 450 °C. The carbide exhibits plasticity and a work-hardening capacity upon compressive loading. Dislocations, twins and torsional deformation are introduced into the larger compressed block-shaped M7C3 carbide. Multiple gliding and twist grain boundaries are firstly observed inside the deformed M7C3 carbide. The corresponding microhardness of the compressed carbide measured at room temperature is found to increase by approximately 100 HV compared to the undeformed one. The plastic deformation behaviors of M7C3 carbide provide a new and valuable understanding of the strain-hardening modes of carbide contained steel and iron materials.