Tensile properties of accident-tolerant aluminum-bearing ferritic steels

•Tensile properties of Al-bearing, high-Cr APMT™ Steel is presented.•The origin of serrated flow in APMT is elucidated.•APMT properties are compared with FeCralloy properties.

Tensile behavior of Kanthal APMT™ steel was studied over a temperature range from room temperature to 500 °C at three strain rates (10−4, 10−3 and 10−2 s−1). Yield strength, ultimate tensile strength and percentage elongation to fracture were evaluated. Serrated plastic flow was observed in a specific temperature/strain rate regime, signifying occurrence of dynamic strain aging (DSA). Characteristic features of DSA such as plateau/peak in yield and tensile strength as a function of temperature, ductility minima and negative strain rate sensitivity were also observed. The activation energy of serrated flow was found to be influenced by diffusion of interstitial impurity modified by high concentration of chromium. Microstructural examination and Vickers hardness testing were also performed on Kanthal APMT™ steel. Room temperature tensile properties of the APMT™ steel were compared with those of Goodfellow FeCralloy™ steel in the light of relevant strengthening mechanisms.