University of Illinois Urbana-Champaign

Modelling of dislocation mobility controlled brittle-to-ductile transition

Nitzsche V R; Hsia, K.J.

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https://hdl.handle.net/2142/112405

Description

Title
Modelling of dislocation mobility controlled brittle-to-ductile transition
Author(s)
  • Nitzsche V R
  • Hsia, K.J.
Issue Date
1993-07
Keyword(s)
  • Brittle-to-ductile Transition
  • Dislocation Mobility
Abstract
The phenomenon of brittle-to-ductile transition (BDT) is known to be controlled by the competition between cleavage fracture and dislocation activity at crack tips. But the transition could be determined by one of the two successive processes, dislocation nucleation, or dislocation motion. The model material is assumed to undergo elastic-rate dependent plastic deformation with the plastic strain rate scaled with dislocation velocity. An isotropic plasticity theory is used. The BDT is assumed to occur when the crack tip is shielded by the surrounding plastic zone such that it never reaches the critical stress intensity for cleavage fracture. The crack tip shielding due to plastic deformation is evaluated using the finite element method. The dimensionless groups which affect the BDT are identified, and a parametric study is performed to reveal the effects of various dimensionless paramters. Numerical results using the specific material properties of Si single crystals are compared with experimental data. Good agreements are obtained. Some interesting features of the BDT behavior are predicted by our computer simulations which require confirmation by experimental studies.
Publisher
Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report Name or Number
  • TAM R 717
  • 1993-6015
ISSN
0073-5264
Type of Resource
text
Language
eng
Permalink
http://hdl.handle.net/2142/112405
Copyright and License Information
Copyright 1993 Board of Trustees of the University of Illinois

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Technical Reports - Theoretical and Applied Mechanics (TAM) PRIMARY
TAM technical reports include manuscripts intended for publication, theses judged to have general interest, notes prepared for short courses, symposia compiled from outstanding undergraduate projects, and reports prepared for research-sponsoring agencies.