scholarly journals Ultralow-temperature superplasticity and its novel mechanism in ultrafine-grained Al alloys

2021 ◽  
Vol 9 (11) ◽  
pp. 475-482
Author(s):  
Nguyen Q. Chinh ◽  
Maxim Yu Murashkin ◽  
Elena V. Bobruk ◽  
János L. Lábár ◽  
Jenő Gubicza ◽  
...  
Keyword(s):  
Al Alloys ◽  
Ultralow Temperature ◽  
Ultrafine Grained

scholarly journals On the origin of the extremely high strength of ultrafine-grained Al alloys produced by severe plastic deformation

2010 ◽  
Vol 63 (9) ◽  
pp. 949-952 ◽  
Author(s):  
R.Z. Valiev ◽  
N.A. Enikeev ◽  
M.Yu. Murashkin ◽  
V.U. Kazykhanov ◽  
X. Sauvage
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
High Strength ◽  
Al Alloys ◽  
Ultrafine Grained

Room Temperature Superplasticity in Fine/Ultrafine-Grained Zn-Al Alloys with Different Phase Compositions

2018 ◽  
Vol 385 ◽  
pp. 72-77
Author(s):  
Muhammet Demirtas ◽  
Harun Yanar ◽  
Onur Saray ◽  
Gençağa Pürçek
Keyword(s):  
Grain Size ◽  
Room Temperature ◽  
Grain Boundary Sliding ◽  
Al Alloys ◽  
Phase Boundaries ◽  
Superplastic Behavior ◽  
Al Content ◽  
Α Phase ◽  
Ultrafine Grained ◽  
Superplastic Elongation

Three Zn-Al alloys, namely Zn-22Al, Zn-5Al and Zn-0.3Al, were subjected to equal-channel angular pressing (ECAP), and the effect of ECAP on their microstructure and room temperature (RT) superplastic behavior were investigated in detail referring to previous studies reported by the authors of the current study. ECAP remarkably refined the microstructures of three alloys as compared to their pre-processed conditions. While the lowest grain size was achieved in Zn-22Al alloy as 200 nm, the grain sizes of Zn-5Al and Zn-0.3Al alloys were ~540 nm and 2 µm, respectively, after ECAP. After the formation of fine/ultrafine-grained (F/UFG) microstructures, all Zn-Al alloys exhibited superplastic behavior at RT and high strain rates. The maximum superplastic elongations were 400%, 520% and 1000% for Zn-22Al, Zn-5Al and Zn-0.3Al alloys, respectively. It is interesting to point out that the highest RT superplastic elongation was obtained in Zn-0.3Al alloy with the largest grain size, while Zn-22Al alloy having the lowest grain size showed the minimum superplastic elongation. This paradox was attributed to the different phase compositions of these alloys. The formation of Al-rich α/α phase boundaries, where grain boundary sliding is minimum comparing to Zn-rich η/η and η/α phase boundaries of Zn-Al alloys, is the lowest level in Zn-0.3Al alloy among all the alloys. Therefore, it can be concluded that if it is desired to achieve high superplastic elongation in Zn-Al alloys at RT, keeping Al content at a possibly minimum level seems to be the most suitable way.

Enhanced mechanical properties in ultrafine grained 7075 Al alloy

2005 ◽  
Vol 20 (2) ◽  
pp. 288-291 ◽  
Author(s):  
Y.H. Zhao ◽  
X.Z. Liao ◽  
Y.T. Zhu ◽  
R.Z. Valiev
Keyword(s):  
Mechanical Properties ◽  
Natural Aging ◽  
Al Alloys ◽  
Coarse Grained ◽  
Tensile Yield Strength ◽  
Al Alloy ◽  
Aged Sample ◽  
Angular Pressing ◽  
7075 Al Alloy ◽  
Ultrafine Grained

Highest strength for 7075 Al alloy was obtained by combining the equal-channel-angular pressing (ECAP) and natural aging processes. The tensile yield strength and ultimate strength of the ECAP processed and naturally aged sample were 103% and 35% higher, respectively, than those of the coarse-grained 7075 Al alloy counterpart. The enhanced strength resulted from high densities of Guinier–Preston (G-P) zones and dislocations. This study shows that severe plastic deformation has the potential to significantly enhance the mechanical properties of precipitate hardening 7000 series Al alloys.

Effect of Cryorolling Strain on Precipitation Kinetics of Al 7075 Alloy

2008 ◽  
Vol 584-586 ◽  
pp. 911-916 ◽  
Author(s):  
R. Jayaganthan ◽  
Sushanta Kumar Panigrahi
Keyword(s):  
Electron Backscatter Diffraction ◽  
Al Alloys ◽  
Thickness Reduction ◽  
Al Alloy ◽  
Precipitation Kinetics ◽  
Heating Rates ◽  
Ultrafine Grained ◽  
Al 7075 ◽  
7075 Alloy ◽  
Kinetics Of

The effect of rolling strain on precipitation kinetics of Al 7075 alloy processed at liquid nitrogen temperature has been investigated in the present work. The Al 7075 alloy plates were solutionized and cryorolled with thickness reduction of 35% and 90%. The microstructural characterizations of the bulk and cryorolled Al alloy samples were carried out by electron backscatter diffraction analysis (EBSD) and transmission electron microscopy (TEM), respectively. The cryorolled Al alloys upon 90% thickness reduction exhibit ultrafine grained microstructure. The DSC results of cryorolled Al 7075 alloys obtained at different heating rates are used to calculate activation energies for the evolution of precipitates. The influence of different reduction rates on activation energy of precipitate formation in the cryorolled Al 7075 alloys was analyzed. The present study has shown that an ultrafine-grained Al 7075 alloy exhibits a higher driving force for the precipitation formation when compared to that of its bulk Al alloys.

Enhanced Strength and Ductility in Hypo-Eutectoid Cu-Al Alloys through ECAP and Annealing

2008 ◽  
Vol 584-586 ◽  
pp. 315-326 ◽  
Author(s):  
Shao Hua Xia ◽  
L.V. Vychigzhanina ◽  
Jing Tao Wang ◽  
Igor V. Alexandrov
Keyword(s):  
Heat Treatment ◽  
Volume Fraction ◽  
Tensile Deformation ◽  
Al Alloys ◽  
Optimal Combination ◽  
Tensile Yield Strength ◽  
Angular Pressing ◽  
Tensile Deformation Behavior ◽  
Ultrafine Grained ◽  
Strength And Ductility

In the present investigation, a bimodal structured alloy with ultrafine-grained (UFG) eutectoid matrix embedded with micrometer-grained pre-eutectoid phase was introduced into the hypo-eutectoid Cu-10.8wt.%Al and Cu-11.3wt.%Al alloys by means of pre-pressing heat-treatment, equal-channel-angular pressing (ECAP) and subsequent annealing. Different size of micrometer grained pre-eutectoid phase was obtained by controlling the cooling rate during pre-pressing heat-treatment of the hypo-eutectoid alloy. The tensile deformation behavior of the developed microstructures is characterized by a maximum tensile yield strength up to 800MPa, which is three times higher than that of the un-treated alloy. It is found that the size of the micrometer grained pre-eutectoid phase is critical to the improvement of the bimodal structured alloy. With larger micrometer grained pre-eutectoid phase, no obvious improvement in plastic elongation was observed with the increase of volume fraction of the pre-eutectoid phase from 20% to 40%, but a decrease in the yield tensile strength was observed. An optimal combination of strength and ductility was obtained particularly in those samples embedded with small-sized micrometer-grained pre-eutectoid phase, which provide extra strain gradient hardening effect.

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