Superior strength-ductility synergy in three-dimensional heterogeneous- nanostructured metals

GD Li and JX Jiang and HC Ma and RX Zheng and S Gao and ST Zhao and CL Ma and K Ameyama and B Ding and XY Li, ACTA MATERIALIA, 256, 119143 (2023).

DOI: 10.1016/j.actamat.2023.119143

Heterogeneous microstructural design has been proven to be an effective strategy in breaking the strength-ductility dilemma in nanostructured metals. However, the precise control of heterogeneous micro-structures to achieve strength-ductility synergy remains challenging. Here, we demonstrate a novel powder metallurgy approach for creating three- dimensional (3D) core-shell nanostructures with highly tunable shell thickness and grain size distributions. These 3D nanostructures enable superior strength-ductility synergy in pure copper, pushing the boundary of the Ashby map to unchartered territory. A combination of microstructural characterization, atomistic simulations and crystal plasticity modeling reveals that the generation and accu-mulation of geometrically necessary dislocations near the core-shell interface play a pivotal role in accommo-dating the strain gradient and sustaining a high strain-hardening rate during plastic deformation. Our work provides a viable approach for designing bulk nanostructured materials with 3D heterogeneous ingredients and demonstrates a promising pathway for the development of strong and ductile materials.

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