Tensile properties of accident-tolerant aluminum-bearing ferritic steels

Abstract

Tensile behavior of Kanthal APMT TM steel was studied over a temperature range from room temperature to 500 o 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 affected by diffusion of interstitial impurity modified by high concentration of chromium. Microstructural examination and Vickers hardness testing were also performed on Kanthal APMT TM steel. Room temperature tensile properties of the APMT TM steel are compared with those of Goodfellow FeCralloy TM steel in the light of operating strengthening mechanisms.

Mechanical properties of neutron-irradiated model and commercial FeCrAl alloys

“…Figure 10 shows the frequency and magnitude of the serrations was significantly minimized at the highest dose (13.8 dpa at 341°C), especially compared with the lower-dose, 7.0 dpa condition. The loss of serrated flow after necking in the 7.0 dpa sample was consistent with the strain rate dependencies shown by Guria and Chairt for Kanthal APMT [24], as the strain rate can be significantly higher during necking than when the material is undergoing uniform plastic deformation. The effect of neutron radiation on dynamic strain aging and serrated flow has been investigated for other Fe-based alloys; see [33,34] and references within.…”

“…The alloy exhibited the highest degree of uniform plastic deformation of any alloy tested when it was tested at high temperature. Furthermore, it showed signs of dynamic strain aging, a result consistent with previous findings for different heats of Kanthal APMT [14,23,24]. Fracture surfaces in the specimens tested at room temperature showed trademark transgranular fracture with faceted textures and river markings ( Figure 2c).…”