Analysis of the Tensile Deformation Behaviors and Microstructure Characterization under Various Temperatures of MarBN Steel by EBSD

Abstract

The uniaxial tensile behavior of MarBN steel with a constant strain rate of 5 × 10−5 s−1 under various temperatures ranging from room temperature to 630 °C was analyzed. This study aimed to identify the effect of the temperature on the tensile behavior and to understand the microstructure deformation by electron backscatter diffraction. The tensile results showed that the yield and ultimate tensile strength decreased with increasing temperature. Serrated flow was observed from 430 °C to 630 °C. The electron backscatter diffraction analysis showed that the low-angle grain boundaries decreased at the medium deformation and increased at the maximum deformation. In contrast, they decreased with increasing temperatures. In addition, the number of voids increased with the increasing plastic strain. As the strain increased, the voids joined together, and the tiny cracks became larger and failed. Three mechanisms were responsible for the tensile deformation failure at various temperatures: grain rotation, the formation and rearrangement of low angle grain boundaries, and void nucleation and propagation. Finally, the formation of the low-angle grain boundaries and voids under different degrees of deformation is discussed.

The cyclic response behavior, failure mechanism, and life prediction model of 9% Cr‐based steel under different strain ratios in the low cyclic fatigue regime at 430°C

“…Meanwhile, the values of K and n are the hardening coefficient and exponent. In addition, the previous studies indicate that the interaction between the diffusion of the solute atoms and the gliding dislocation at high temperatures, [41][42][43] leads to the mobile dislocation and tangling along the slip path, resulting in a downward trend of the strain hardening exponent with the increase of the temperature. Additionally, the values of H c , σ UTS, and σ y are the strain hardening ratio, the tensile, and yield strength.…”