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Title: Binary dislocation junction formation and strength in hexagonal close-packed crystals

This work examines binary dislocation interactions, junction formation and junction strengths in hexagonal close-packed (hcp ) crystals. Through a line-tension model and dislocation dynamics (DD) simulations, the interaction and dissociation of different sets of binary junctions are investigated involving one dislocation on the (011¯0) prismatic plane and a second dislocation on one of the following planes: (0001) basal, (11¯00) prismatic, (11¯01) primary pyramidal, or (2¯112) secondary pyramidal. Varying pairs of Burgers vectors are chosen from among the common types the basal type < a > 1/3 < 112¯0 >, prismatic type < c > <0001>, and pyramidal type < a+c > 1/3 < 112¯3¯ >. For binary interaction due to dislocation intersection, both the analytical results and DD-simulations indicate a relationship between symmetry of interaction maps and the relative magnitude of the Burgers vectors that constitute the junction. Using analytical formulae, a simple regressive model is also developed to represent the junction yield surface. The equation is treated as a degenerated super elliptical equation to quantify the aspect ratio and tilting angle. Lastly, the results provide analytical insights on binary dislocation interactions that may occur in general hcp metals.
Authors:
 [1] ;  [2] ;  [2] ;  [3]
  1. U.S. Army Research Lab., Aberdeen Proving Ground, MD (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Univ. of Maryland, College Park, MD (United States); U.S. Army Research Lab., Adelphi, MD (United States)
Publication Date:
OSTI Identifier:
1367989
Report Number(s):
LLNL-JRNL-702744
Journal ID: ISSN 0749-6419; PII: S0749641915002028
Grant/Contract Number:
AC52-07NA27344; ORISE-1120-1120-99
Type:
Accepted Manuscript
Journal Name:
International Journal of Plasticity
Additional Journal Information:
Journal Volume: 79; Journal ID: ISSN 0749-6419
Publisher:
Elsevier
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; dislocations; dynamics; elastic material; analytic functions