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

2010 ◽  
Vol 667-669 ◽  
pp. 331-336 ◽  
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.

Thermal Stability of Ultrafine-Grained Pure Titanium Processed by High-Pressure Torsion

2021 ◽  
Vol 1016 ◽  
pp. 338-344
Author(s):  
Wan Ji Chen ◽  
Jie Xu ◽  
De Tong Liu ◽  
De Bin Shan ◽  
Bin Guo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Grain Size ◽  
High Pressure ◽  
Annealing Temperature ◽  
High Pressure Torsion ◽  
Stored Energy ◽  
Ultrafine Grained ◽  
Average Grain Size ◽  
Thermal Stability Of

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.

Structure and Fatigue Properties of the Mg Alloy AM60 Processed by ECAP

2008 ◽  
Vol 584-586 ◽  
pp. 803-808 ◽  
Author(s):  
Rinat K. Islamgaliev ◽  
Olya B. Kulyasova ◽  
Bernhard Mingler ◽  
Michael Zehetbauer ◽  
Alexander Minkow
Keyword(s):  
Grain Size ◽  
Endurance Limit ◽  
Volume Fraction ◽  
Coarse Grained ◽  
Fatigue Properties ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Mean Grain Size ◽  
Fatigue Endurance ◽  
Misorientation Angles

This paper reports on the microstructures and fatigue properties of ultrafine-grained (UFG) AM60 magnesium alloy processed by equal channel angular pressing (ECAP) at various temperatures. After ECAP processing, samples exhibited an increase in fatigue endurance limit, which correlates well with a decrease in grain size. In case of lowest ECAP temperature, the mean grain size is as small as 1 2m which leads to an increase in fatigue endurance limit by 70 % in comparison to coarse-grained alloy. The temperature of ECAP not only governs the grain size and misorientation angles of grain boundaries but also the volume fraction of precipitates, thus affecting the probability of twinning and grain growth after fatigue treatment.

scholarly journals Thermal Stability of Titanium Alloy VT8M-1 with Ultrafine-Grained Structure

2020 ◽  
Vol 321 ◽  
pp. 11026
Author(s):  
A.G. Stotskiy ◽  
A.V. Polyakov ◽  
G.S. Dyakonov ◽  
I.P. Semenova
Keyword(s):  
Thermal Stability ◽  
Coarse Grained ◽  
Structural Elements ◽  
Electronic Microscopy ◽  
Rotary Swaging ◽  
Long Duration ◽  
Ultrafine Grained ◽  
Equiaxed Grains ◽  
Thermal Stability Of

The paper considers the effect of a long-duration heating at a service temperature of 450oC on VT8M-1 with a coarse-grained (CG) and ultrafine-grained (UFG) microstructure. A duplex ultrafine-grained microstructure, composed of equiaxed grains of primary α-phase and an ultrafine constituent of α- and β-phases, was processed by thermal treatment and further rotary swaging. This type of a microstructure demonstrates a best combination of strength and ductility at room temperature in comparison with the CG structure. A thermal stability of an UFG state was studied at 450°C for 50, 100, 200, 300, 400, and 500 hours. The evolution of the alloy microstructure against the duration of heating was considered by transmission electronic microscopy (TEM), scanning electronic microscopy (SEM). No increase in the alloy structural elements and strength decrease resulting from a long-term annealing (up to 500 hours) at T=450°C have been observed. This proves a high thermal stability of the UFG structure and mechanical properties of VT8M-1 processed via rotary swaging.

Evolution of Structure and Phase Composition of Aluminum Alloy under Severe Plastic Deformation

2014 ◽  
Vol 880 ◽  
pp. 179-183
Author(s):  
Evgeniy V. Naydenkin ◽  
Konstantin V. Ivanov ◽  
Gennadiy E. Rudenskii
Keyword(s):  
Crystal Structure ◽  
Thermal Stability ◽  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Severe Plastic Deformation ◽  
S Phase ◽  
High Thermal Stability ◽  
Ultrafine Grained ◽  
Evolution Of Structure ◽  
Thermal Stability Of

The paper shows that high thermal stability of the ultrafine-grained structure of aluminum alloy produced by severe plastic deformation is related to S-phase particles. The sequence of phase transformations of zirconium-doped ultrafine-grained alloy Al-Mg-Li in heating is revealed. The paper also determines temperatures at which depending on crystal structure two types of S-phase particles can form.

Structure and Properties of Ultrafine-Grained Cu-Cr Alloys after High Pressure Torsion

2010 ◽  
Vol 667-669 ◽  
pp. 301-306 ◽  
Author(s):  
D.V. Shangina ◽  
N.R. Bochvar ◽  
Sergey V. Dobatkin
Keyword(s):  
Thermal Stability ◽  
Chromium Content ◽  
High Pressure Torsion ◽  
Softening Temperature ◽  
Initial State ◽  
Resistivity Measurements ◽  
Chromium Alloys ◽  
Ultrafine Grained ◽  
The Stability ◽  
Thermal Stability Of

The effect of chromium content (0.75, 9.85, 27%) and initial state on the thermal stability of copper-chromium alloys after severe plastic deformation has been studied by microhardness and electrical resistivity measurements. The stability of the structures is established to depend on the initial state of the alloys and on the content of chromium phase. In the low-alloy bronze, quenching before HPT substantially increases the thermal stability of the alloy relative to that observed after annealing. The softening temperature increases with increasing chromium phase content and reaches 450°C for the alloy with 27% Cr.

scholarly journals Thermal stability of a nanocrystalline HfNbTiZr multi-principal element alloy processed by high-pressure torsion

2020 ◽  
Vol 168 ◽  
pp. 110550 ◽  
Author(s):  
Pham Tran Hung ◽  
Megumi Kawasaki ◽  
Jae-Kyung Han ◽  
János L. Lábár ◽  
Jenő Gubicza
Keyword(s):  
Thermal Stability ◽  
High Pressure ◽  
High Pressure Torsion ◽  
Principal Element ◽  
Thermal Stability Of

Grain Refinement and Deformation Behavior of Ultrafine Grained Pd and Pd-Ag Alloys Produced by HPT

2008 ◽  
Vol 584-586 ◽  
pp. 182-187
Author(s):  
Lilia Kurmanaeva ◽  
Yulia Ivanisenko ◽  
J. Markmann ◽  
Ruslan Valiev ◽  
Hans Jorg Fecht
Keyword(s):  
Mechanical Properties ◽  
Deformation Behavior ◽  
Materials Science ◽  
High Pressure Torsion ◽  
Uniform Elongation ◽  
Grain Structure ◽  
Coarse Grained ◽  
Ultrafine Grain ◽  
Ultrafine Grained ◽  
Ultrafine Grain Structure

Investigations of mechanical properties of nanocrystalline (nc) materials are still in interest of materials science, because they offer wide application as structural materials thanks to their outstanding mechanical properties. NC materials demonstrate superior hardness and strength as compared with their coarse grained counterparts, but very often they possess a limited ductility or show low uniform elongation due to poor strain hardening ability. Here, we present the results of investigation of the microstructure and mechanical properties of nc Pd and Pd-x%Ag (x=20, 60) alloys. The initially coarse grained Pd-x% Ag samples were processed by high pressure torsion, which resulted in formation of homogenous ultrafine grain structure. The increase of Ag contents led to the decrease of the resulted grain size and change in deformation behavior, because of decreasing of stacking fault energy (SFE). The samples with larger Ag contents demonstrated the higher values of hardness, yield stress and ultimate stress. Remarkably the uniform elongation had also increased with increase of strength.

Effect of Pre-Strain Rolling on Annealing Behavior of Friction-Stir Welded AA6061-T6 Aluminum Alloy

2018 ◽  
Vol 385 ◽  
pp. 355-358 ◽  
Author(s):  
Sergey Mironov ◽  
Sergey Malopheyev ◽  
Igor Vysotskiy ◽  
Daria Zhemchuzhnikova ◽  
Rustam Kaibyshev
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Aluminum Alloy ◽  
Cold Rolling ◽  
Grain Growth ◽  
Rolling Schedule ◽  
Annealing Behavior ◽  
Friction Stir ◽  
Welding Direction ◽  
Thermal Stability Of

In this work, the effect of pre-strain cold rolling on thermal stability of friction-stir welded AA6061-T6 alloy was studied. The pre-strain rolling was found to be very effective in suppression of abnormal grain growth during standard post-weld T6 heat treatment. It was also shown that the efficiency of this approach essentially depends on rolling path and the rolling along welding direction was the most effective rolling schedule.

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