Monotonous deformation behavior of ferritic FeCrAl alloy in the dynamic strain aging regime

Abstract

Monotonous deformation behavior of a ferritic FeCrAl alloy at a temperature range from room temperature to 600 °C was studied using the uniaxial tensile tests. The results showed that dynamic strain aging (DSA) occurred at a strain rate of 3.333 × 10−4s−1 over the temperature range from 200 °C to 400 °C. Tensile tests were carried out at four different strain rates in the DSA temperature domain to investigate the combined action of temperature and strain rate on DSA. Negative strain rate sensitivity of ultimate tensile strength (UTS) was observed as the characteristic manifestation of DSA performed in FeCrAl alloy. It was also found out that, type A, A+B, B, C+D and C serrations appeared in turn in the stress-strain curves tested at a constant strain rate with the increase of temperature, and the decrease in strain rate shifted the DSA temperature range toward the lower temperature region. Statistical method was used on stress drops with DSA to investigate the character of serration. From the activation energy calculations with Mccormick's model, the solute atoms responsible for DSA were identified to be substitutional aluminum atoms.