Thermal evolution and grain boundary phase transformations in severely deformed nanograined Al–Zn alloys

Straumal, Boris B.; Valiev, R. Z.; Kogtenkova, O. A.; Zięba, P.; Czeppe, T.; Bielańska, Elżbieta; Faryna, M.

doi:10.1016/j.actamat.2008.08.021

Cited by 101 publications

(59 citation statements)

References 51 publications

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“…The torsion torque increased during 1-2 anvil rotations in all alloys and pure Ti and then remained almost unchanged. In other words, it reached a steady state, as was observed previously in other alloys [16][17][18][19][20]51,52]). The central part (about 3 mm in diameter) of each disk after HPT was excluded from further investigations (since it is low-deformed).…”

Section: Methodssupporting

confidence: 67%

“…SPD also induces various phase transformations [12] such as formation [13][14][15] or decomposition [16][17][18][19][20] of supersaturated solid solution, dissolution of particles of a second solid phase [21][22][23][24][25][26], amorphization [27][28][29][30][31][32] and nanocrystallization [33][34][35]. Among this variety, very interesting are the phase transformations with formation of high-pressure phases.…”

Section: Introductionmentioning

confidence: 99%

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The α → ω Transformation in Titanium-Cobalt Alloys under High-Pressure Torsion

Kilmametov

Ivanisenko

Straumal

et al. 2017

Metals

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Abstract:The pressure influence on the α → ω transformation in Ti-Co alloys has been studied during high pressure torsion (HPT). The α → ω allotropic transformation takes place at high pressures in titanium, zirconium and hafnium as well as in their alloys. The transition pressure, the ability of high pressure ω-phase to retain after pressure release, and the pressure interval where α and ω phases coexist depend on the conditions of high-pressure treatment. During HPT in Bridgeman anvils, the high pressure is combined with shear strain. The presence of shear strain as well as Co addition to Ti decreases the onset of the α → ω transition from 10.5 GPa (under quasi-hydrostatic conditions) to about 3.5 GPa. The portion of ω-phase after HPT at 7 GPa increases in the following sequence: pure Ti → Ti-2 wt % Co → Ti-4 wt % Co → Ti-4 wt % Fe.

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Section: Methodssupporting

confidence: 67%

Section: Introductionmentioning

confidence: 99%

The α → ω Transformation in Titanium-Cobalt Alloys under High-Pressure Torsion

Kilmametov

Ivanisenko

Straumal

et al. 2017

Metals

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“…This is consistent with the earlier experimental data reported, e.g. for pure aluminium and aluminium alloys [4,8,[34][35][36][37], high purity copper and copper alloys [13-17, 38, 39], nickel [40,41], steel [42,43], etc.…”

Section: Microstructure and Texture Of The Deformed Statesupporting

confidence: 82%

Tem Study of Recrystallization in Ultra-Fine Grain AA3104 Alloy Processed by High-Pressure Torsion

Paul¹,

Morawiec²,

Baudin³

et al. 2015

Archives of Metallurgy and Materials

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The effect of annealing on the microstructure and the texture development was investigated in a particle containing AA3104 aluminium alloy. The samples were processed at room temperature by high-pressure torsion (HPT) up to ten turns. The nucleation of new grains was analyzed by a transmission electron microscope equipped with a system for local orientation measurements and a heating holder.The shear deformation induces a decrease of the grain size. After the first two turns of the HPT processing the initial structure of large grains was 'transformed' into a structure of fine cells/grains with the diameter of a few tens of nanometers. In the central areas of the samples the elongated shape of the cells/grains was observed up to six turns. For higher deformations, this structural inhomogeneity was totally removed and only the equiaxed grains were observed. The crystal lattice of small grains rotates in such a way that the <111> direction is parallel to the compression axis. After annealing the structure coarsened. Nevertheless, after primary recrystallization, the structure was still composed of relatively fine and equiaxed grains of a similar size. In most of the observed cases the size of the recrystallized grains in the areas close to and far from the large second phase particles was similar. The recrystallization leads to the creation of new texture components. The new grain orientations lost the positions typically observed in the deformed state and showed the tendency for the coincidence of the <100> crystallographic directions with the compression axis.Keywords: High Pressure Torsion, AA3104 alloy, TEM orientation mapping, Texture, Microstructure W pracy analizowano wpływ warunków wyżarzania na zmiany mikrostrukturalne i teksturowe w stopie AA3104 zawierającym wydzielenia cząstek drugiej fazy. Próbki odkształcano z wykorzystaniem techniki skręcania pod wysokim ciśnieniem (HPT), do dziesięciu obrotów, w temperaturze otoczenia. Proces zarodkowania nowych ziaren analizowano z wykorzystaniem transmisyjnej mikroskopii elektronowej wyposażonej w system pomiaru orientacji lokalnych oraz 'heating holder'.Zaobserwowano, że w miarę wzrostu liczby obrotów, intensywne ścinanie prowadzi do silnego zmniejszenia wielkości ziarna. Po dwu obrotach, wyjściowa struktura dużych ziaren uległa przekształceniu w strukturę drobnoziarnistą złożoną z ziaren o wielkości kilkudziesięciu nanometrów. W obszarach próbki zbliżonych do osi obrotu wydłużony kształt ziaren obserwowano do sześciu obrotów. W zakresie wyższych stopni odkształcenia ta niejednorodność strukturalna zanika; obserwowano jedynie równoosiowe ziarna. Orientacja sieci krystalicznej tych ziaren formuje silną teksturę osiową z kierunkiem <111> usytuowanym równolegle do kierunku normalnego (osi ściskania/skręcania). Po wyżarzaniu struktura ulega 'pogrubieniu'. Jednakże, w zakresie rekrystalizacji pierwotnej, w dalszym ciągu pozostaje równoosiowa i silnie rozdrobniona. W większości obserwowanych przypadków wielkość zrekrystalizowanych ziaren w obszarach położonych zarówno ...

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“…1. The experimental evidence for the existence of a GB liquid-like phase between GB solidus line and bulk solidus line was obtained by transmission electron microcopy (TEM) [26] and differential scanning calorimetry (DSC) for the Al-Zn alloys [27]. In the area between GB solidus and bulk solidus, GB contains the thin layer of a GB phase.…”

Section: Resultsmentioning

confidence: 99%

“…The grains of the Al-based solid solution appear light grey. It has to be underlined that the Al/Al 3 Mg 2 interphase boundaries (IBs) are not smooth (like for example the Al/ Zn interphase boundaries in the Al-Zn alloys are [7,26,27]). Most probably it is due to the strong anisotropy of the interfacial energy of Al/Al 3 Mg 2 IBs.…”

Section: Resultsmentioning

confidence: 99%

Wetting of grain boundaries in Al by the solid Al3Mg2 phase

Straumal

Baretzky²,

Kogtenkova

et al. 2009

J Mater Sci

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The microstructure of binary Al 100-x -Mg x (x = 10, 15, 18 and 25 wt%) alloys after long anneals (600-4000 h) was studied between 210 and 440°C. The transition from incomplete to complete wetting of Al/Al grain boundaries (GBs) by the second solid phase Al 3 Mg 2 has been observed. The portion of completely wetted GBs increases with increasing temperature beginning from T wsmin = 220°C. Above T wsmax = 410°C all Al/Al GBs are completely wetted by the Al 3 Mg 2 phase.

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Thermal evolution and grain boundary phase transformations in severely deformed nanograined Al–Zn alloys

Cited by 101 publications

References 51 publications

The α → ω Transformation in Titanium-Cobalt Alloys under High-Pressure Torsion

The α → ω Transformation in Titanium-Cobalt Alloys under High-Pressure Torsion

Tem Study of Recrystallization in Ultra-Fine Grain AA3104 Alloy Processed by High-Pressure Torsion

Wetting of grain boundaries in Al by the solid Al3Mg2 phase

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