Balancing strength and ductility of cylindrical-shaped Cu64Zr36 nanoglass via embedded Cu nanocrystals

Abstract

Large-plasticity can be realized in nanoglass at the expense of strength, and such a loss can be compensated by embedding stronger nanocrystals. Here, the effects of average grain size (Daverage) and volume fraction of nanocrystalline (ϕ) on deformation behaviors of cylindrical-shaped Cu64Zr36 nanoglass/crystalline Cu composites (NGCCs) are investigated by molecular dynamics simulations of tensile loading. Our results reveal that the necking behavior of NGCCs persistently starts from the glass grains, followed by the glass fracture. In particular, there exists a critical Daverage of 7.96 nm, which is related to the diameter of nanowires. With Daverage larger than the critical value, NGCCs are more likely to achieve both high-strength and large-ductility in comparison with their NG counterparts. It also confirms the significance of the surface effect on stretching NGCC nanowires. As the volume fraction of the Cu nanograins increases, the peak stress of NGCCs increases while the ductility decreases. Therefore, the tweaking of appropriate Daverage and ϕ makes it possible to overcome the long-term strength-ductility trade-off dilemma.