Investigation of the Effect of 475 °C Aging Treatment on Mechanical Properties of a Fe–19Cr–5.5Al ODS Alloy Using Tensile, Impact and Small Punch Tests

Abstract

The effect of thermal aging on the mechanical properties of a Fe–19Cr–5.5Al oxide dispersion strengthened (ODS) hot rolled steel plate was evaluated. Tensile tests, sub-size Charpy impact tests, microhardness measurements and small punch tests were performed to analyze the embrittlement phenomenon occurring at an aging temperature of 475 °C as a consequence of a miscibility gap in the Fe–Cr system. These mechanical tests were able to confirm the age hardening and its intensity grade at different testing temperatures. Fractured impact and small punch specimens exhibited parallel delaminations promoted by a microstructure formed by elongated ferritic grains with a texture being 〈110〉 along the rolling direction. This study has revealed that small punch test represents a valuable technique for assessing the embrittlement susceptibility of high-Cr ODS alloys at different operational temperatures.