Study on Mechanical Properties and Deformation Mechanism of Fe-28Mn-10Al-C High-Strength Steel during Dynamic Deformation Process

Abstract

For the purpose of investigating the microstructure deformation of 28Mn-10Al-C steel at high speeds under different strain rates, the dynamic properties of 28Mn-10Al-C steel under varying strain rates and the feasibility of the tensile specimens with a variable cross-section were evaluated using a combination of tensile test, optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscope (SEM), and electron back scatter diffraction (EBSD). The test results demonstrate that the high-tension tensile process of 28Mn-10Al-C steel involves a competitive process of work hardening, deformation speed reinforcement, and adiabatic temperature elevation. The elasticity limit, tensile strength, and elongation of 28Mn-10Al-C steel increase with the rate of deformation. Specifically, at a deformation rate of 103 s−1, the yield strength, tensile strength, and elongation of the test steel increase to 817 MPa, 1047 MPa, and 60.6%, respectively, indicating significant improvements in all properties. Through analyzing its mechanical properties, dislocation density, and angle grain boundary density, this article discusses the deformation behavior of 28Mn-10Al-C steel during dynamic deformation. It is found that the dominant hardening mechanism and softening mechanism in the deformation process change with the increase in strain rate.