A molecular dynamics investigation of the dependence of mechanical properties of steel nanowires on C concentration

TL;DR

This study uses molecular dynamics simulations to explore how varying carbon content and temperature affect the mechanical properties of steel nanowires, revealing key trends in their strength and deformation behavior.

Contribution

It introduces a detailed analysis of the temperature and C concentration dependence of steel nanowires' mechanical properties using validated interatomic potentials.

Findings

Young's modulus increases up to 300 K then decreases at higher temperatures with more C.

Yield stress and UTS decrease as C content increases.

Slip plane formation and propagation are enhanced at higher C and temperatures.

Abstract

The temperature dependence of mechanical properties of steel nanowires with varying carbon content was studied using molecular dynamics simulations. Four interatomic potentials were assessed, with the Modified Embedded Atom Method (MEAM) potential developed by Liyanage et al. selected for its accuracy in predicting the behavior of BCC Fe, FeC in the B1 rock salt structure, and BCC iron with carbon. Uniaxial tensile tests were conducted on FeC nanowires with carbon concentrations of 0-10% at temperatures ranging from 0.1 K to 900 K. Stress-strain curves were analyzed to determine Young's modulus, yield stress, and ultimate tensile strength (UTS). Results showed that Young's modulus increased between 0.1 K and 300 K but decreased between 600 K and 900 K with increasing carbon content. Both yield stress and UTS decreased progressively with higher carbon percentages. Common Neighbor Analysis revealed rapid formation of slip planes as carbon content increased and greater slip plane propagation at elevated temperatures, contributing to reduced nanowire strength. These findings provide insights into the influence of carbon content and temperature on the mechanical behavior of steel nanowires, which may inform the design of nanostructured steel materials for various applications.