Strain Rate Contribution due to Dynamic Recovery of Ultrafine-Grained Cu–Zr as Evidenced by Load Reductions during Quasi-Stationary Deformation at 0.5 Tm

During quasi-stationary tensile deformation of ultrafine-grained Cu-0.2 mass%Zr at 673 K and a deformation rate of about 10−4 s−1 load changes were performed. Reductions of relative load by more than about 25% initiate anelastic back flow. Subsequently, the creep rate turns positive again and goes t...

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Bibliographic Details
Published in:Metals (Basel ) 2019-11, Vol.9 (11), p.1150
Main Authors: Blum, Wolfgang, Dvořák, Jiři, Král, Petr, Eisenlohr, Philip, Sklenička, Vaclav
Format: Article
Language:English
Subjects:
Alloys
Anelasticity
Boundaries
Creep rate
cu–zr
deformation
dynamic recovery
ecap
load change tests
Recovery
Residual stress
Strain hardening
Strain rate
Subtraction
Temperature
Tensile deformation
transient
ultrafine-grained material
Ultrafines
Zirconium
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Summary:During quasi-stationary tensile deformation of ultrafine-grained Cu-0.2 mass%Zr at 673 K and a deformation rate of about 10−4 s−1 load changes were performed. Reductions of relative load by more than about 25% initiate anelastic back flow. Subsequently, the creep rate turns positive again and goes through a relative maximum. This is interpreted by a strain rate component ϵ ˙ − associated with dynamic recovery of dislocations. Back extrapolation indicates that ϵ ˙ − contributes the same fraction of ( 20 ± 10 ) % to the quasi-stationary strain rate that has been reported for coarse-grained materials with high fraction of low-angle boundaries; this suggests that dynamic recovery of dislocations is generally mediated by boundaries. The influence of anelastic back flow on ϵ ˙ − is discussed. Comparison of ϵ ˙ − to the quasi-stationary rate points to enhancement of dynamic recovery by internal stresses. Subtraction of ϵ ˙ − from the total rate yields the rate component ϵ ˙ + related with generation and storage of dislocations; its activation volume is in the order expected from the classical theory of thermal glide.
ISSN:2075-4701
2075-4701
DOI:10.3390/met9111150