Moderate rolling for producing effective heterostructure

Abstract

Severe cold rolling followed by recrystallization has been widely used to produce heterostructures for superior strength-ductility combinations in metallic materials. However, this requires a thick feeding stock and has high processing cost due to severe rolling strain. Here we report that only moderate rolling is needed to produce an effective heterostructure for high yield strength and good ductility in FeCrNi medium entropy alloys (MEA). Moderate rolling plus partial recrystallization produces a unique heterostructure, in which the recrystallized zones is harder than the unrecrystallized zones. This is formed by a mechanism that is very different from what is reported for severely cold-rolled metals. The strategy developed here has notable advantages in terms of high efficiency, low cost, and superior mechanical properties, rendering it applicable for a wide range of alloy systems.