Cryorolling is one of the potential techniques to produce
nanostructured bulk materials from its bulk counterpart at cryogenictemperatures. It can be defined as rolling that is carried out at cryogenic temperatures. Nanostructured materials are produced chiefly by severe plastic deformation processes. The majority of these methods require large plastic deformations (strains much larger than unity). In case of cryorolling, the deformation in the strain hardened metals is preserved as a result of the suppression of the dynamic recovery. Hence large strains can be maintained and after subsequent annealing, ultra- fine-grainedstructure can be produced.
Comparison of cryorolling and rolling at room temperature:
* In Cryorolling, the strain hardening is retained up to the extent to which rolling is carried out. This implies that there will be no
dislocation annihilationand dynamic recovery. Whereas in rolling at room temperature, dynamic recovery is inevitable and softening takes place.
flow stressof the material differs for the sample which is subjected to cryorolling. A cryorolled sample has a higher flow stress compared to a sample subjected to rolling at room temperature.
Cross slipand climb of dislocations are effectively suppressed during cryorolling leading to high dislocation densitywhich is not the case for room temperature rolling.
corrosion resistanceof the cryorolled sample comparatively decreases due to the high residual stress involved.
* The number of
electron scattering centres increases for the cryorolled sample and hence the electrical conductivitydecreases significantly.
* The cryorolled sample shows a high
* Ultra-fine-grained structures can be produced from cryorolled samples after subsequent annealing.
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