Comparative study on Mechanical characteristics of Functionally graded and Coreshell nanospheres: An Atomistic approach

TL;DR

This study uses molecular dynamics simulations to compare the mechanical properties of functionally graded and core-shell nanospheres, revealing differences in strength and dislocation behavior at the nanoscale.

Contribution

It provides the first atomistic comparison of mechanical characteristics between FGM and core-shell nanospheres under compression.

Findings

Core-shell nanospheres exhibit higher mechanical strength than FGM nanospheres.

Distinct patterns in ultimate stress variation are observed between the two nanosphere types.

Dislocation analysis links stress variation to partial dislocation densities.

Abstract

Functionally Graded Material (FGM) is a type of advanced material consisting of two (or more) distinct substances with a constantly changing composition profile. FGM technologies have moved from their traditional use to advanced micro and nanoscale electronics and energy conversion systems along with the advent of nanotechnology. MD simulations are used in this analysis to examine the effect of compressive load on Ag-Au FGM and Core-shell nanospheres. The plasticity process is often started by the nucleation of partial dislocations from the contact surfaces, and these dislocations spread towards the nanosphere's center. Also, we have found the formation of pyramidal-shaped partial dislocations on the pseudo-plastic regime. For a given wt% range of Ag in Au, Coreshell nanospheres have stronger mechanical strength than FGM nanospheres, and we have also observed two distinct patterns in ultimate stress variation for FGM and Coreshell nanospheres. The dislocation analysis suggests a correlation between this stress variation and the Shockley & Hirth partial dislocation density.