Atomistic Design of High Strength Crystalline-Amorphous Nanocomposites

Abstract

There is a long-standing demand for materials which could simultaneously demonstrate multiple promising properties like high strength, good ductility and toughness. In this study, a three-dimensional bulk nanocomposite material which is composed of nanoscale crystalline metal and metallic glass is revealed to present high strength and potentially good ductility by molecular dynamics. A critical high strength is achieved by varying the ratio between crystalline and amorphous phase. The critical strength is revealed to be higher than that expected from the rule of mixture. The mechanism underlying the occurrence of critical strength in the nanocomposite is elucidated by the interaction between dislocation and matrix of amorphous phase. Our concept could guide the engineers to design more advanced bulk nanostructured materials.

Plastic deformation due to interfacial sliding in amorphous/crystalline nanolaminates

“…Investigation of the ACI may help to understand the mechanical properties of BMG-based composites. A deformation map of the dislocation emission and annihilation at the ACI and the transformation from dislocation to STZ was preliminarily illustrated by Wang et al [23] and further elaborated by others [25,27,28]. However, the structural change of the amorphous layer induced by the presence of an ACI has not been fully studied, and the effect of such a change on the deformation of the amorphous layer remains unclear.…”

Interface-Related Shear Banding Deformation of Amorphous/Crystalline CuZr/Cu Nanolaminates by Molecular Dynamics Simulations

“…Inserting a soft crystalline phase into the amorphous phase was recently found to be an effective method to resolve this issue. Numerous experimental ndings [1][2][3][4][5][6][7] and molecular dynamics (MD) studies [8][9][10] had revealed a combination of high strength and good ductility in nanoscaled amorphous/crystalline nanolaminates (A/CNLs). The enhanced strength was attributed to both of the two constituent metallic layers 11) , and the better plastic deformability was induced from the easily strain-accommodated amorphous/crystalline interface (ACI).…”

Mechanistic coupling of dislocation and shear transformation zone plasticity in crystalline-amorphous nanolaminates

“…Atomistic nanolaminate models are particularly convenient for direct investigation of deformation mechanisms as a function of the hierarchical structural length scales and deformation conditions (e.g. temperature, strain rate, loading direction) [43]. The triggering of STZs upon the absorption of dislocations in the amorphous layers was demonstrated in the uniaxial tensile simulations conducted by Wang et al [18] on nanolaminates containing single crystal Cu layers.…”