Research Papers

Determination of Dislocation Interaction Strengths Using Discrete Dislocation Dynamics of Curved Dislocations

[+] Author and Article Information
Alankar Alankar1

 School of Mechanical and Materials Engineering,  Washington State University, P.O. Box 642920, Pullman, WA 99164;  Materials Science Division, MS-G755,  Los Alamos National Laboratory, Los Alamos, NM 87544alankar@lanl.gov

Ioannis N. Mastorakos, David P. Field

 School of Mechanical and Materials Engineering,  Washington State University, P.O. Box 642920, Pullman, WA 99164

Hussein M. Zbib

 School of Mechanical and Materials Engineering,  Washington State University, P.O. Box 642920, Pullman, WA 99164;  Pacific Northwest National Laboratory, Richland, WA 99352


Corresponding author.

J. Eng. Mater. Technol 134(2), 021018 (Mar 27, 2012) (4 pages) doi:10.1115/1.4005917 History: Received June 29, 2011; Revised November 03, 2011; Published March 27, 2012; Online March 27, 2012

In latent interactions of dislocations, junction formation is one of the most important phenomena that contribute to the evolution of strength. In this work, the latent hardening coefficients for pure aluminum are estimated using 3D multiscale dislocation dynamics program (MDDP). Three well-known junction configurations, namely, the Hirth lock, the glissile junction, and the Lomer lock, are studied using 3D discrete dislocation dynamics simulations. The evolution of strength is discussed as a function of the resolved shear stress (RSS) and the number of junctions for the three junctions investigated. Hirth lock and Lomer lock are found to be the weakest and strongest junctions, respectively. Collinear reaction of dislocations does not form a junction but causes a higher strength than a Lomer lock. Quantitative and qualitative results are compared with those found in the literature.

Copyright © 2012 by American Society of Mechanical Engineers
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Grahic Jump Location
Figure 1

Views of DD simulations showing the formation of (a) Hirth locks, (b) glissile junctions, (c) Lomer locks, and (d) collinear interactions. The legends show different slip planes and junctions. The junctions (no. 6 on legend) are the segments encircled in black color. In all the simulations, mobile dislocations are on plane 3. In (a), (b), and (c) the forest dislocations are on plane 4 and in (d) the forest dislocations are on plane 1.

Grahic Jump Location
Figure 2

Evolution of resolved shear stress (RSS) with respect to plastic strain for Hirth lock, glissile junction, Lomer lock, and collinear annihilation

Grahic Jump Location
Figure 3

Number of junctions/locks formed for (a) Hirth lock, (b) glissile junction, and (c) Lomer lock plotted with RSS as a function of plastic strain



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