A forest model of latent hardening and its application to polycrystal deformation

Conference · Mon Jan 01 00:00:00 EST 1990

DOI:https://doi.org/10.1155/TSM.14-18.1103· OSTI ID:5882262

Kocks, U F ^[1]; Franciosi, P ^[2]; Kawai, M ^[3]

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1. Los Alamos National Lab., NM (USA)
2. Paris-13 Univ., 93 - Villetaneuse (France)
3. Tsukuba Univ., Ibaraki (Japan). Inst. of Engineering Mechanics

This paper means to assess latent hardening effects on large-scale polycrystal deformation on the basis of the dislocation theory of plastic flow and of a wide variety of experimental observations on single crystals. The qualifier large-scale is introduced to eliminate effects during the earliest stages of flow, where mono- and polycrystals behave differently: the authors will not consider easy glide in single crystals; and they will not consider the gradual transition, over perhaps ten times the elastic strain, to polyslip in polycrystals; or, for that matter, initial Lueders-type deformation in polycrystals. In terms of dislocation theory, they will consider the flow stress to mean the percolation limit of dislocations in areal glide. Dislocation theory will be used at a rather gross level. Experience has shown that many of the details of the interactions between dislocations and of their arrangement are of surprisingly little influence on macroscopic plastic behavior. They will present a latent hardening model that is based on the well established forest model of flow stress and strain hardening. They will present a latent hardening model that is based on the well established forest model of flow stress and strain hardening. They will then assess various pieces of experimental and theoretical evidence that limit the number and magnitude of the parameters and predict the direction in which they might depend on stacking-fault energy. Finally, they will summarize results obtained by polycrystal simulation in which the model was implemented. They show only marginal effects, and only in certain cases.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5882262
• Report Number(s): LA-UR-91-965; CONF-9009236-4; ON: DE91009964
• Resource Relation: Journal Volume: 14; Conference: 9. international conference on textures of materials, Avignon (France), 17-21 Sep 1990
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
METALS
DEFORMATION
POLYCRYSTALS
ANISOTROPY
DISLOCATIONS
FLOW STRESS
HARDENING
MATHEMATICAL MODELS
MONOCRYSTALS
PLASTICITY
SLIP
STACKING FAULTS
STRAIN HARDENING
TEXTURE
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTALS
ELEMENTS
LINE DEFECTS
MECHANICAL PROPERTIES
STRESSES
360103* - Metals & Alloys- Mechanical Properties