2026 DeLeo 3D Interfaces Nanolaminates

Metal nanolaminates achieve exceptional strength through interface-mediated plasticity, but atomically sharp two-dimensional interfaces concentrate stress at dislocation pileups, promoting shear localization and limiting deformability. This study synthesizes prior experimental and computational results across nanolaminate systems to establish a transferable design framework for simultaneously enhancing strength and suppressing strain localization by replacing these sharp interfaces with structurally extended three-dimensional interfaces (3DIs) of controlled thickness. Utilizing phase-field dislocation dynamics (PFDD) simulations, crystal plasticity finite element modeling, and various experimental techniques including atom probe tomography and nanoindentation across Cu/Nb and Ti/Nb nanolaminates, we identify conditions under which 3DIs provide maximum mechanical enhancement. PFDD results indicate that slip transmission resistance increases with interface thickness and saturates at approximately 5-20 nm. Experimental measurements in Cu/Nb reveal a performance window constrained by interface thickness. In Ti/Nb, 3DIs enhance hardness by 28% and suppress shear localization at large strains. Overall, these findings support three transferable design rules for interface-engineered nanolaminates: target the PFDD strength saturation regime, constrain bilayer period, and minimize slip transmission asymmetry.