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Title: A dislocation-based, strain–gradient–plasticity strengthening model for deformation processed metal–metal composites

Deformation processed metal–metal composites (DMMCs) are high-strength, high-electrical conductivity composites developed by severe plastic deformation of two ductile metal phases. The extraordinarily high strength of DMMCs is underestimated using the rule of mixture (or volumetric weighted average) of conventionally work-hardened metals. A dislocation-density-based, strain–gradient–plasticity model is proposed to relate the strain-gradient effect with the geometrically necessary dislocations emanating from the interface to better predict the strength of DMMCs. The model prediction was compared with our experimental findings of Cu–Nb, Cu–Ta, and Al–Ti DMMC systems to verify the applicability of the new model. The results show that this model predicts the strength of DMMCs better than the rule-of-mixture model. The strain-gradient effect, responsible for the exceptionally high strength of heavily cold worked DMMCs, is dominant at large deformation strain since its characteristic microstructure length is comparable with the intrinsic material length.
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  1. Iowa State Univ., Ames, IA (United States); Ames Lab., Ames, IA (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
IS-J 8733
Journal ID: ISSN 0022-2461; PII: 7982
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Materials Science
Additional Journal Information:
Journal Volume: 49; Journal Issue: 7; Journal ID: ISSN 0022-2461
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
Country of Publication:
United States
36 MATERIALS SCIENCE; intrinsic material length; true strain; hardening model; immobile dislocation; dislocation density; couple stress theory; taylor factor; work-hardening model; slip system; severe plastic deformation