Improving deformability of brittle intermetallics via introducing mobile dislocations across coherent interfaces

Abstract

Intermetallics are generally brittle at room temperature, severely limiting their applications. Using CoAl 100 nm/Fe 10 nm nanolaminate as a model system, we demonstrate a strategy for improving deformability of brittle intermetallics via introducing mobile dislocations across coherent interfaces. High-density pre-existing mobile dislocations are introduced into Fe layers via ion peening. In situ micropillar compression tests show the model system has high yield strength, 3.5 GPa, and sustainable work hardening to 5 GPa with substantial uniform plastic deformation, exhibiting superior strength-deformability synergy. Transmission electron microscopy studies reveal the mobile dislocations continuously propagate from Fe into CoAl across the coherent interface, accommodating the considerable plastic deformation. This study provides a fresh perspective for enhancing room temperature plasticity in a wide range of brittle materials.