Comparative analysis of inelastic strain recovery and plastic deformation in coarse-grained samples of Ti49.3Ni50.7 (at %) alloy under torsion and bending

The effects of severe plastic deformation (SPD) by isothermal rolling at the temperature of liquid nitrogen combined with prior- and post-SPD heat treatment, on microstructure and hardness of Al-4.4%Cu-1.4%Mg-0.7%Mn (D16) alloy were investigated. It was found no nanostructuring even after straining to 75%. Сryodeformation leads to microshear banding and processing the high-density dislocation substructures with a cell size of ~ 100-200 nm. Such a structure remains almost stable under 1 hr annealing up to 200oC and with further temperature increase initially transforms to bimodal with a small fraction of nanograins and then to uniform coarse grained one. It is found the change in the alloy post–SPD aging response leading to more active decomposition of the preliminary supersaturated aluminum solid solution, and to the alloy extra hardening under aging with shorter times and at lower temperatures compared to T6 temper.

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Modern Models of Grain Boundary Diffusion

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.312-315.1116 ◽

2011 ◽

Vol 312-315 ◽

pp. 1116-1125

Author(s):

Vladimir V. Popov

Keyword(s):

Plastic Deformation ◽

Grain Boundary ◽

Severe Plastic Deformation ◽

Nanocrystalline Materials ◽

Boundary Diffusion ◽

Grain Boundary Diffusion ◽

Coarse Grained ◽

Gas Condensation ◽

Non Equilibrium

Recent models of grain-boundary diffusion are briefly reviewed. Models of diffusion along equilibrium boundaries of recrystallization origin in coarse-grained materials and along non-equilibrium boundaries in nanocrystalline materials obtained by gas condensation and compacting or by severe plastic deformation are considered separately.

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Aging Behaviour of Al-Mg-Si Alloys Subjected to Severe Plastic Deformation by ECAP and Cold Asymmetric Rolling

Journal of Metallurgy ◽

10.1155/2011/959643 ◽

2011 ◽

Vol 2011 ◽

pp. 1-8 ◽

Cited By ~ 20

Author(s):

S. Farè ◽

N. Lecis ◽

M. Vedani

Keyword(s):

Plastic Deformation ◽

Severe Plastic Deformation ◽

Isothermal Aging ◽

Room Temperature ◽

Coarse Grained ◽

Peak Shape ◽

Asymmetric Rolling ◽

Ultrafine Grained ◽

Aging Kinetics ◽

Reduced Intensity

A study was carried out on aging behaviour of a 6082 alloy processed by two different severe plastic deformation techniques: ECAP and asymmetric rolling. Both techniques were able to generate an ultrafine-grained structure in samples processed at room temperature. It was stated that severe straining promotes marked changes in the postdeformation aging kinetics. The peaks of β′′/β′ transition phases were anticipated and of progressively reduced intensity over the coarse grained alloy. A further peak accounting for onset of recrystallization also appeared in the most severely deformed samples. Full consistency in peak shape and position was found when comparing materials processed by ECAP and asymmetric rolling. Isothermal aging treatments performed at 180°C revealed that in the severely deformed samples, aging became so fast that the hardness curves continuously decreased due to overwhelming effects of structure restoration. On the contrary, aging at 130°C offers good opportunities for fully exploiting the precipitate hardening effects in the ultrafine-grained alloy.

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