skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Quasi-equilibrium modeling of the toughness transition during semibrittle cleavage

Abstract

A discretized dislocation model is used to assess the quasi-static equilibrium, crack tip emission and shielding of near-tip dislocations for Mo single crystals. As in a previous study for Fe-3wt% Si, based partly on the Rice-Thomson criterion, this model leads to a failure prediction for Mo both consistent with the absence of an expected dislocation free zone and the observed toughness transition over the test temperature range. While cleavage is the failure mode in the semibrittle regimes of these two b.c.c. crystals, K[sub Ic] values vary from 5 up to 60 MPa-m[sup 1/2] with an increase in test temperature. The equilibrium solution for both metals from the discrete dislocation model is reconnected with ordinary continuum theory through the CTOD and plastic zone size, as well as Weertman's hypothesis of the nonredundant/redundant dislocation decomposition for near-tip microplasticity. The similarities in zeroth order successive approximation solutions derived for these two metals, with very disparate elastic anisotropies, suggests that such approaches may also be applicable to semibrittle ordered intermetallics.

Authors:
;  [1]
  1. (Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Science)
Publication Date:
OSTI Identifier:
5119233
DOE Contract Number:  
FG02-84ER45141; FG02-88ER45337
Resource Type:
Journal Article
Journal Name:
Acta Metallurgica et Materialia; (United States)
Additional Journal Information:
Journal Volume: 42:3; Journal ID: ISSN 0956-7151
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; MOLYBDENUM ALLOYS; DISLOCATIONS; FRACTURE PROPERTIES; MATHEMATICAL MODELS; TRANSITION TEMPERATURE; ALLOYS; CRYSTAL DEFECTS; CRYSTAL STRUCTURE; LINE DEFECTS; MECHANICAL PROPERTIES; PHYSICAL PROPERTIES; THERMODYNAMIC PROPERTIES; 360103* - Metals & Alloys- Mechanical Properties; 360102 - Metals & Alloys- Structure & Phase Studies

Citation Formats

Huang, H., and Gerberich, W.W.. Quasi-equilibrium modeling of the toughness transition during semibrittle cleavage. United States: N. p., 1994. Web. doi:10.1016/0956-7151(94)90260-7.
Huang, H., & Gerberich, W.W.. Quasi-equilibrium modeling of the toughness transition during semibrittle cleavage. United States. doi:10.1016/0956-7151(94)90260-7.
Huang, H., and Gerberich, W.W.. Tue . "Quasi-equilibrium modeling of the toughness transition during semibrittle cleavage". United States. doi:10.1016/0956-7151(94)90260-7.
@article{osti_5119233,
title = {Quasi-equilibrium modeling of the toughness transition during semibrittle cleavage},
author = {Huang, H. and Gerberich, W.W.},
abstractNote = {A discretized dislocation model is used to assess the quasi-static equilibrium, crack tip emission and shielding of near-tip dislocations for Mo single crystals. As in a previous study for Fe-3wt% Si, based partly on the Rice-Thomson criterion, this model leads to a failure prediction for Mo both consistent with the absence of an expected dislocation free zone and the observed toughness transition over the test temperature range. While cleavage is the failure mode in the semibrittle regimes of these two b.c.c. crystals, K[sub Ic] values vary from 5 up to 60 MPa-m[sup 1/2] with an increase in test temperature. The equilibrium solution for both metals from the discrete dislocation model is reconnected with ordinary continuum theory through the CTOD and plastic zone size, as well as Weertman's hypothesis of the nonredundant/redundant dislocation decomposition for near-tip microplasticity. The similarities in zeroth order successive approximation solutions derived for these two metals, with very disparate elastic anisotropies, suggests that such approaches may also be applicable to semibrittle ordered intermetallics.},
doi = {10.1016/0956-7151(94)90260-7},
journal = {Acta Metallurgica et Materialia; (United States)},
issn = {0956-7151},
number = ,
volume = 42:3,
place = {United States},
year = {1994},
month = {3}
}