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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.

a b s t r a c tAluminum-bearing APMT™ steel is being considered as a potential fuel cladding material for a novel light water reactor design. Elevated temperature tensile tests were performed with APMT™ steel to examine the basic mechanical behavior. Serrations observed in the temperature range of 523-673 K during tensile deformation of APMT™ within a range of strain rates are attributed to dynamic strain aging (DSA) with negative strain rate sensitivity. The DSA effect was due to interactions between mobile dislocations and interstitial solute atoms whose mobility was affected by the presence of high concentration of substitutional solute atoms.

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