Enabling microstructural changes of FCC/BCC alloys in 2D dislocation dynamics

TL;DR

This paper extends 2D dislocation dynamics models to include microstructural features of FCC/BCC alloys, incorporating defect distributions, loop accumulation, and friction effects to better simulate material behavior under various conditions.

Contribution

It introduces new features into dislocation dynamics simulations, such as defect distribution, loop accumulation, and friction, tailored for FCC/BCC alloys based on experimental data.

Findings

Model captures defect distribution effects on yield strength.

Incorporates loop accumulation dynamics.

Analyzes friction contribution to dislocation motion.

Abstract

Dimension reduction procedure is the recipe to represent defects in two dimensional dislocation dynamics according to the changes in the geometrical properties of the defects triggered by different conditions such as radiation, high temperature, or pressure. In the present study, this procedure is extended to incorporate further features related to the presence of defects with a special focus on face-centered cubic/body-centered cubic alloys used for diverse engineering purposes. In order to reflect the microstructural state of the alloy on the computational cell of two dimensional dislocation dynamics, the distribution of the multi-type defects over slip lines is implemented by using corresponding strength and line spacing for each type of defect. Additionally, a simple recursive incremental relation is set to count the loop accumulation on the precipitates. In the case of continuous resistance against the motion of edge dislocations on the slip lines, an expression of friction is introduced to see its contribution on the yield strength. Each new property is applied independently on a different material by using experimental information about defect properties and grain sizes under the condition of plain strain deformation: both constant and dynamically increasing obstacle strength for precipitate coarsening in prime-aged and heat-treated copper-chromium-zirconium, internal friction in tantalum-2.5tungsten, and mixed hardening due to the presence of precipitates and prismatic loops in irradiated oxide dispersion strengthened EUROFER with 0.3% yttria.