Unexpected microstructural evolution of FeCrAl heat-resistant alloy under electrical heating: Potential risks in industrial electrification

• Annealing is accelerated under electrical heating compared to conventional heating. • The athermal effect of electric current accelerates M 23 C 6 precipitation. • Preexisting inclusions grow abnormally due to the athermal effect of electric current. • Overlapping annealing, precipitation, and growth lead to altered mechanical behavior. • This study suggests the need to develop electric current- and heat- resistant alloys. Electrification of industrial heating is a promising route to decarbonize manufacturing and improve energy efficiency. Yet, the influence of electric current, particularly its athermal effects, on the microstructural stability and mechanical integrity of electrically heated materials remains largely unexplored. Here, we report that electrical heating (EH) of a FeCrAl heat-resistant alloy induces irreversible microstructural transformations that differ fundamentally from those observed under conventional heating (CH), despite identical temperature profiles. EH-treated specimens show increased strength, suppressed yield-point behavior, and a notable loss of ductility. These changes arise from athermal effects of electric current, which accelerate carbide precipitation and compensate for annealing-induced softening, while also promoting abnormal coarsening of preexisting Al-rich inclusions that act as crack initiation sites. Our findings demonstrate that electric current alters the thermomechanical response of heat-resistant alloys, highlighting the urgent need to develop heat- and current-resistant materials specifically designed for electrically powered industrial environments.