Complexity and Anisotropy of Plastic Flow of α-Ti Probed by Acoustic Emission and Local Extensometry

Current progress in the prediction of mechanical behavior of solids requires understanding of spatiotemporal complexity of plastic flow caused by self-organization of crystal defects. It may be particularly important in hexagonal materials because of their strong anisotropy and combination of differ...

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Bibliographic Details
Published in:Materials 2018-06, Vol.11 (7), p.1061
Main Authors: Lebyodkin, Mikhail, Amouzou, Kékéli, Lebedkina, Tatiana, Richeton, Thiebaud, Roth, Amandine
Format: Article
Language:English
Subjects:
Acoustic emission
Acoustics
Alloys
Anisotropy
Avalanches
Complexity
Crystal defects
Crystallography
Deformation mechanisms
Dislocations
Distribution functions
Elastoplasticity
Engineering Sciences
Experiments
Extensometers
Hypotheses
Materials
Mechanical properties
Multiplication & division
Multiscale analysis
Plastic flow
Probability distribution functions
Recording
Statistical analysis
Strain hardening
Twinning
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Summary:Current progress in the prediction of mechanical behavior of solids requires understanding of spatiotemporal complexity of plastic flow caused by self-organization of crystal defects. It may be particularly important in hexagonal materials because of their strong anisotropy and combination of different mechanisms of plasticity, such as dislocation glide and twinning. These materials often display complex behavior even on the macroscopic scale of deformation curves, e.g., a peculiar three-stage elastoplastic transition, the origin of which is a matter of debates. The present work is devoted to a multiscale study of plastic flow in α-Ti, based on simultaneous recording of deformation curves, 1D local strain field, and acoustic emission (AE). It is found that the average AE activity also reveals three-stage behavior, but in a qualitatively different way depending on the crystallographic orientation of the sample axis. On the finer scale, the statistical analysis of AE events and local strain rates testifies to an avalanche-like character of dislocation processes, reflected in power-law probability distribution functions. The results are discussed from the viewpoint of collective dislocation dynamics and are confronted to predictions of a recent micromechanical model of Ti strain hardening.
ISSN:1996-1944
1996-1944
DOI:10.3390/ma11071061