|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Mechanical Behavior at the Nanoscale III
||Mechanistic Coupling of Dislocation and Shear Transformation Zone Plasticity in Crystalline-Amorphous Nanolaminates
||Bin Cheng, Jason Trelewicz
|On-Site Speaker (Planned)
Metallic nanolaminates composed of periodically alternating nanocrystalline and amorphous layers represent new hierarchically structured materials that simultaneously exhibit exceptional strength and ductility. In this study, molecular dynamics simulations of nanolaminates containing columnar nanograins were conducted to quantify the plastic strain distribution among competing mechanisms using continuum deformation metrics. Initially, plastic strain was accommodated within the amorphous layers with shear transformation zone activity favoring atoms near the amorphous-crystalline interfaces (ACIs). Relative to nanolaminates free of grain boundaries, this enhanced slip was further biased to amorphous atoms near the intersection of ACIs with grain boundary planes. Lattice dislocations were emitted from these regions of locally high shear strain, and the grain boundaries significantly reduced the stresses required for global yielding via dislocation plasticity. Absorption of dislocations at the ACIs suppressed strain accommodation at the grain boundaries, which eliminated the formation of deleterious stress concentrations that ultimately lead to grain boundary microcracking.
||Planned: A print-only volume