Nano-lamellar materials with ultrahigh strengths and unusual physical properties are of technological importance for structural applications. However, these materials generally suffer from low tensile ductility, which severely limits their practical utility. Here we show that markedly enhanced tensile ductility can be achieved in coherent nano-lamellar alloys, which exhibit an unprecedented combination of over 2 GPa yield strength and 16% uniform tensile ductility. The ultrahigh strength originates mainly from the lamellar boundary strengthening, whereas the large ductility correlates to a progressive work-hardening mechanism regulated by the unique nano-lamellar architecture. The coherent lamellar boundaries facilitate the dislocation transmission, which eliminates the stress concentrations at the boundaries. Meanwhile, deformation-induced hierarchical stacking-fault networks and associated high-density Lomer-Cottrell locks enhance the work hardening response, leading to unusually large tensile ductilities. The coherent nano-lamellar strategy can potentially be applied to many other alloys and open new avenues for designing ultrastrong yet ductile materials for technological applications.

Finding the fivefold path: Crystals formed in nature or synthesized in a lab can have domains with different orientations that are called twins. Having five of these domains is relatively common, but how these fivefold twins form is still a mystery. Song et al. combined in situ transmission electron microscope observations with simulations to find two different pathways for forming fivefold twins in gold, platinum, and palladium nanoparticles. This combination provides a key insight into the twin-forming process, which might be exploited for developing nanoparticles suitable for a variety of applications. Science , this issue p. 40