Molecular dynamics simulations of interaction between a super edge dislocation and interstitial dislocation loops in irradiated L12-Ni3Al

TL;DR

This paper uses molecular dynamics simulations to explore how a super-edge dislocation interacts with interstitial dislocation loops in irradiated L12-Ni3Al, revealing detailed mechanisms and energetic variations relevant to irradiation hardening.

Contribution

It extends dislocation-IDL interaction theory from FCC to L12 lattices, providing new insights into irradiation effects in Ni3Al alloys.

Findings

Identified dislocation reactions and structural evolution during interactions.

Clarified slipping and looping mechanisms of Shockley partials.

Observed variations in critical shear stress based on IDL configurations.

Abstract

The study employed MD simulations to investigate the interactions between a <110> super-edge dislocation, consisting of the four Shockley partials, and interstitial dislocation loops (IDLs) in irradiated L12-Ni3Al. Accounting for symmetry breakage in the L12 lattice, the superlattice planar faults with four distinct fault vectors have been considered for different IDL configurations. The detailed dislocation reactions and structural evolution events were identified as the four partials interacted with various IDL configurations. The slipping characteristics of Shockley partials within the IDLs and the resultant shearing and looping mechanisms were also clarified, revealing distinct energetic transition states determined by the fault vectors after the Shockley partials sweeping the IDL. Furthermore, significant variations in critical resolved shear stress (CRSS) required for the super-edge dislocation to move past the IDL were observed, attributed to various sizes and faulted vectors of enclosed superlattice planar faults in the IDLs. The current study extends the existing dislocation-IDL interaction theory from pristine FCC to L12 lattice, advances the understanding of irradiation hardening effects in L12-Ni3Al, and suggests potential applicability to other L12 systems.