Thermal stability of ultrafine grained AA8090 Al–Li alloy processed by repetitive corrugation and straightening

High-pressure torsion (HPT) was conducted under 6.0 GPa on commercial purity titanium up to 10 turns. An ultrafine-grained (UFG) pure Ti with an average grain size of ~96 nm was obtained. The thermal properties of these samples were studied by using differential scanning calorimeter (DSC) which allowed the quantitative determination of the evolution of stored energy, the recrystallization temperatures, the activation energy involved in the recrystallization of the material and the evolution of the recrystallized fraction with temperature. The results show that the stored energy increases, beyond which the stored energy seems to level off to a saturated value with increase of HPT up to 5 turns. An average activation energy of about 101 kJ/mol for the recrystallization of 5 turns samples was determined. Also, the thermal stability of the grains of the 5 turns samples with subsequent heat treatments were investigated by microstructural analysis and Vickers microhardness measurements. It is shown that the average grain size remains below 246 nm when the annealing temperature is below 500 °C, and the size of the grains increases significantly for samples at the annealing temperature of 600 °C.

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Thermal stability of ultrafine grained Fe–Cr–Ni alloy

Materials Science and Engineering A ◽

10.1016/j.msea.2012.02.033 ◽

2012 ◽

Vol 542 ◽

pp. 64-70 ◽

Cited By ~ 24

Author(s):

C. Sun ◽

Y. Yang ◽

Y. Liu ◽

K.T. Hartwig ◽

H. Wang ◽

...

Keyword(s):

Thermal Stability ◽

Ultrafine Grained ◽

Ni Alloy ◽

Thermal Stability Of

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Enhanced Thermal Stability and Mechanical Properties of Ultrafine-Grained Aluminum Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.667-669.331 ◽

2010 ◽

Vol 667-669 ◽

pp. 331-336 ◽

Cited By ~ 2

Author(s):

Rinat K. Islamgaliev ◽

Marina A. Nikitina ◽

Aidar F. Kamalov

Keyword(s):

Thermal Stability ◽

Aluminum Alloy ◽

Volume Fraction ◽

High Pressure Torsion ◽

Coarse Grained ◽

Dynamic Precipitation ◽

Ultrafine Grained ◽

The Mean ◽

Fatigue Endurance ◽

Thermal Stability Of

The paper reports on microstructure, strength and fatigue of ultrafine-grained (UFG) samples of the Al-Cu-Mg-Si aluminum alloy processed by high pressure torsion (HPT) at various temperatures. Application of the HPT treatment led to strong grain refinement, as well as to a raise of the mean-root square strains and dynamic precipitation. In case of optimal HPT treatment the UFG samples have demonstrated the enhanced thermal stability, an increase in ultimate tensile strength in 2.5 times and enhancement in fatigue endurance limit by 20 % in comparison with coarse-grained alloy subjected to standard treatment. It is shown that the regime of the HPT treatment governs the volume fraction of precipitates and segregations, thereby affecting a grain size and thermal stability of ultrafine-grained structure.

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