Propagation of shear bands and accommodation of shear strain in the Fe56Nb4Al40 ultrafine eutectic-dendrite composite

Abstract

Microstructural investigations of Fe56Nb4Al40 ultrafine eutectic-dendrite composite reveal that its high room temperature plasticity mainly originates from the evolution of slip in the dendrites and multiple shear banding in the ultrafine eutectic matrix, respectively. Here, we sequentially describe that the shear bands in the ultrafine eutectic matrix are propagated with generation of strain field in the soft alpha-Fe(Al) layers rather than passing through by sharp shear banding in the hard (Fe,Al)2Nb intermetallic layers. Consequently, step morphologies at the interfaces of the alternating lamellae and the dendrite/eutectic matrix strongly support the effective accommodation of shear strain during shear band propagation.