Quasi-equilibrium modeling of the toughness transition during semibrittle cleavage

Journal Article · Tue Mar 01 04:00:00 EST 1994 · Acta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-7151(94)90260-7· OSTI ID:5119233

Huang, H; Gerberich, W W ^[1]

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1. Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Science

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.

• DOE Contract Number: FG02-84ER45141; FG02-88ER45337
• OSTI ID: 5119233
• Journal Information: Acta Metallurgica et Materialia; (United States), Journal Name: Acta Metallurgica et Materialia; (United States) Vol. 42:3; ISSN 0956-7151; ISSN AMATEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DISLOCATIONS
FRACTURE PROPERTIES
LINE DEFECTS
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
MOLYBDENUM ALLOYS
PHYSICAL PROPERTIES
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE