The mechanism of nanocrystalline structure formation in Ni3Al during severe plastic deformation

Корзников, А. В.; Tram, G.; Dimitrov, O.; Korznikova, G. F.; Idrisova, S.R.; Pakieła, Zbigniew

doi:10.1016/s1359-6454(00)00345-1

Cited by 88 publications

(49 citation statements)

References 12 publications

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“…A typical disordered fcc structure without any superstructure peak or peak splitting was observed for both states. In agreement with some earlier studies on long range ordered intermetallics processed by SPD, [15,16,21] the ordered L1 0 phase was disordered by SPD.…”

Section: Ordered State Processed By Hptsupporting

confidence: 91%

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Optimization of the Magnetic Properties of FePd Alloys by Severe Plastic Deformation

et al. 2010

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A FePd alloy was nanostructured by severe plastic deformation following two different routes: ordered and disordered states were processed by high pressure torsion (HPT). A grain size in a range of 50 to 150 nm is obtained in both cases. Severe plastic deformation induces some significant disordering of the long range ordered L1 0 phase. However, Transmission Electron Microscopy (TEM) data clearly show that few ordered nanocrystals remain in the deformed state. The deformed materials were annealed to achieve nanostructured long range ordered alloys. The transformation proceeds via a first order transition characterized by the nucleation of numerous ordered domains along grain boundaries. The influence of the annealing conditions (temperature and time) on the coercivity was studied for both routes. It is demonstrated that starting with the disorder state prior to HPT and annealing at low temperature (400°C) leads to the highest coercivity (about 1.8 kOe).

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Section: Ordered State Processed By Hptsupporting

confidence: 91%

“…Ultrafine grain materials are commonly achieved by SPD processes, [2,3] and it has been demonstrated that grain sizes smaller than 100 nm can be obtained in intermetallics. [15,16] The present study aims at using such processes to optimize the magnetic properties of an equi-atomic intermetallic FePd alloy by nanostructuring.…”

Section: Introductionmentioning

confidence: 99%

Optimization of the Magnetic Properties of FePd Alloys by Severe Plastic Deformation

et al. 2010

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“…The High-Pressure Torsion (HPT) method opened a pathway to investigate these compounds since the large torsion deformation is applied under quasi-hydrostatic conditions which significantly suppress the fracture. A number of intermetallic compounds, such as TiNi, 1,2) Ni 3 Al, [3][4][5][6] Cu 3 Au, 7) ZrCu, 8) and Zr 3 Al, 9) have been subjected to HPT deformation which, aside from the expected grain refinement, resulted in various interesting phenomena, e.g. amorphization, disordering, and/or shear band formation.…”

Section: Introductionmentioning

confidence: 99%

“…Korznikov et al 6) pointed out that the addition of B increases the thermal stabilities of the nano-grained structures in HPT-deformed Ni 3 Al. The process of nanocrystalline structure formation during HPT deformation was studied by Korznikov et al 4) They reported a heterogeneous structure composed of highly misoriented nanocrystalline areas and microcrystalline areas with high densities of defects including dislocations and twins. They have found that the first stage of the nanostructure formation is the fragmentation of grains by the formation of deformation twins, followed by the development of misorientation between the fragments and eventually leading to disordered equiaxed nano-grains.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous Process of Disordering and Structural Refinement in Ni<SUB>3</SUB>Al during Severe Plastic Deformation by High-Pressure Torsion

et al. 2010

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The process of grain refinement in Ni 3 Al by high-pressure torsion (HPT) was investigated up to 100 turns. The entire diametric sections of the deformed samples were analyzed by optical microscopy and image processing methods in order to evaluate both the spatial distribution and the volume fractions of the nanocrystalline and coarse grains. A thick band of nanocrystalline phase was formed in the middle section of the samples, and a structure containing mainly coarser ordered fragments was present in the vicinity of the top and bottom surfaces. Pseudotwinning along {111} was observed at the boundaries of coarse-fragmented grains as well as the inside of the fragments and is put forward as a possible mechanism for disordering and nanocrystalline structure formation in Ni 3 Al.

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“…Second, by subjecting samples of pure Ti to HPT after processing by ECAP where it was demonstrated that there was an additional reduction in the grain size from~300 nm to~200 nm [7]. In addition, whereas the grain sizes attained in ECAP are generally in the submicrometer range of~100-1,000 nm, numerous reports are now available documenting grain sizes of <100 nm in materials processed by HPT: for example, nanometer grains sizes have been reported in various Al alloys [8][9][10], a Cu nanocomposite [11], various Ni alloys [12,13], Ni 3 Al [14][15][16], Ti-6% Al-4% V [17] and various steels [10,[18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Evolution of microstructure and microtexture in fcc metals during high-pressure torsion

2006

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Pure nickel and commercially pure (CP) aluminium were selected as model fcc materials for a detailed investigation of the experimental parameters influencing grain refinement and evolution of microstructure and microtexture during processing by highpressure torsion (HPT). Samples were examined after HPT using microhardness measurements, transmission electron microscopy and orientation imaging microscopy. Processing by HPT produces a grain size of 170 nm in pure Ni and~1 lm in CP aluminium. It is shown that homogeneous and equiaxed microstructures can be attained throughout the samples of nickel when using applied pressures of at least~6 GPa after 5 whole revolution. In CP aluminium, a homogeneous and equiaxed microstructure was achieved after 2 whole revolutions under an applied pressure of 1 GPa. For these conditions, the distributions of grain boundary misorientations are similar in the centre and at the periphery of the samples. It is shown that simple shear texture develops in fcc metals subjected to highpressure torsion. Some grain growth was detected at the periphery of the Al disk after 8 revolutions. The factors influencing the development of homogeneous microstructures in processing by HPT are discussed.

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The mechanism of nanocrystalline structure formation in Ni3Al during severe plastic deformation

Cited by 88 publications

References 12 publications

Optimization of the Magnetic Properties of FePd Alloys by Severe Plastic Deformation

Optimization of the Magnetic Properties of FePd Alloys by Severe Plastic Deformation

Heterogeneous Process of Disordering and Structural Refinement in Ni<SUB>3</SUB>Al during Severe Plastic Deformation by High-Pressure Torsion

Evolution of microstructure and microtexture in fcc metals during high-pressure torsion

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