Molecular dynamics simulation to elucidate effects of spatial geometry on interactions between an edge dislocation and rigid, impenetrable precipitate in Cu

• Published in: Computational materials science Vol. 215; p. 111806
• Main Authors: Tsugawa, K., Hayakawa, S., Okita, T., Aichi, M., Itakura, M., Suzuki, K.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2022
• Subjects: Hirsch mechanism; Orowan loop; Partial dislocation; Precipitate hardening; Vacancy loop; Precipitate hardening; Orowan loop; Hirsch mechanism; Partial dislocation; Vacancy loop
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2022.111806

[Display omitted] •Simulation where precipitate center does not lie on glide plane of edge dislocation.•Formation of a vacancy loop below the glide plane and Hirsch loops above the plane.•Hardening asymmetry with respect to case where center lies on glide plane.•Smaller precipitate-hardening by estimation of elasticity theory. Molecular dynamics simulations were conducted to evaluate the interactions between an edge dislocation and a rigid, impenetrable precipitate in Cu by changing the distance between the glide plane of the dislocation and the center of the precipitate (ξ). In these calculations, the precipitate was introduced as a super particle that moved according to the total force exerted by the matrix atoms on the precipitate atoms. When the center of the precipitate was close to the glide plane, an Orowan loop was formed around the precipitate after the dislocation detached, and the critical resolved shear stress (CRSS) was similar to the value evaluated by the results at ξ = 0. However, when the glide plane was far from the center of the precipitate, either a vacancy loop or loops generated through the Hirsch mechanism were formed, depending on whether the center of the precipitate was below or above the glide plane. The magnitude of the CRSS was not symmetric about ξ = 0. This study confirmed that it is necessary to analyze the CRSS by changing ξ to construct a predictive model for the hardening caused by the formation of lattice defects, and that precipitate hardening appears to be smaller than the value estimated using the results at ξ = 0.