Strain-Rate-Dependent Deformation Behavior of High-Carbon Steel under Tensile–Compressive Loading

Abstract

High-carbon low-alloy steels with a dual-phase structure of austenite and martensite are widely used for cutting tools and in mining industries due to their excellent abrasion resistance and strength properties. The aim of this paper is to critically assess the tension–compression asymmetry behavior over a wide range of quasistatic strain rates. Experiments were conducted at four different strain rates (2.56 × 10−4/s to 2.56 × 10−1/s) under uniaxial tensile and compressive loading. The experimental results indicated an increasing trend in the yield strength in tension and compression as the strain rate was increased. It was observed that the influence of the strain rate on the phase transformation behavior had no significant effect on the tensile-loaded specimens. On the other hand, the martensitic transformation was found to be rate dependent in the compression-loaded specimens. Electron backscatter diffraction studies indicated an increase in the grain average misorientation values with an increase in the strain rate. The fracture surface revealed the presence of transgranular and intergranular cracks for the samples deformed at low (2.56 × 10−4/s) and high (2.56 × 10−1/s) strain rates during compressive loading. On the other hand, ridges and cleavage steps were found for the samples deformed under tensile loading. Transmission electron microscopy revealed the formation of dislocation cells and discontinuous blocks of martensite for tensile-loaded specimens, whereas formation of subgrains and a decrease in the lath martensite with an increase in the strain rate were found to be the dominant features for the compressive-loaded specimens.