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D. Gromov

Bio: D. Gromov is an academic researcher. The author has contributed to research in topics: Superplasticity & Alloy. The author has an hindex of 3, co-authored 3 publications receiving 64 citations.

Papers
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TL;DR: In this article, the superplastic properties and microstructure evolution of a 0.15%Zr and 0.7%Cu modified 6061 aluminium alloy were examined in tension at temperatures ranging from 475 to 600°C and strain rates ranging from 7 × 10-6 to 2.8× 10-2 s-1.
Abstract: The superplastic properties and microstructure evolution of a 0.15%Zr and 0.7%Cu modified 6061 aluminium alloy were examined in tension at temperatures ranging from 475 to 600°C and strain rates ranging from 7 × 10-6 to 2.8 × 10-2 s-1. The refined microstructure with an average grain size of about 11 μm was produced in thin sheets by a commercially viable thermomechanical process. It was shown that the modified 6061 alloy exhibits a moderate superplastic elongation of 580% in the entirely solid state at 570°C and ϵ = 2.8 × 10-4 s-1. Superior superplastic properties (elongation to failure of 1300% with a corresponding strain rate sensitivity coefficient m of about 0.65) were found at the same strain rate and a temperature of 590°C, which is higher than the incipient melting point of the 6061 alloy (~575°C). The microstructural evolution during superplastic deformation of the 6061 alloy has been studied quantitatively. The presence of a slight amount of liquid phase greatly promotes the superplastic...

19 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that a 0.15%Zr+0.7%Cu modified 6061 aluminum alloy with an initial grain size of about 11 μm exhibits a maximum elongation-to-failure of 1300% at 590 °C and an initial strain rate of 2.8×10−4 s−1 in a partially melted state.

16 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, an Al-Li-Mg-Sc alloy with an initial grain size of ∼60μm was processed by equal-channel angular extrusion (ECAE) at 300°C up to a total strain of 12.
Abstract: An Al–Li–Mg–Sc alloy with an initial grain size of ∼60 μm was processed by equal-channel angular extrusion (ECAE) at 300 °C up to a total strain of 12. Transmission electron microscopy (TEM) and orientation imaging microscopy (OIM) were employed to establish the mechanism of grain refinement. It was found that new ultrafine grains evolved by a strain-induced continuous process, which is termed continuous dynamic recrystallization (CDRX). At ɛ ∼ 1, a well-defined subgrain structure had developed. Upon further straining the average mis-orientation of deformation-induced boundaries increased; low-angle boundaries (LAB) gradually converted into true high-angle boundaries (≥15°) (HAB). At ɛ ∼ 4, arrays of boundaries with low and high angle mis-orientations were observed. At ɛ ∼ 12, a structure dominated by HAB with an average grain size of ∼0.9 μm was formed. This size is roughly similar to that for subgrains developed at preceding strains. It was shown that CDRX occurs homogeneously; the formation of new grains takes place both along initial boundaries and within interiors of original grains as well.

197 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of initial microstructure on the deformation behavior of a 2219 aluminum alloy was examined and the activation energies for deformation Q for state 1, state 2 and state 3 were computed to be 166, 223 and 172 kJ−mol −1, respectively.

76 citations

Journal ArticleDOI
TL;DR: In this paper, an age-hardenable 2219 Al-Cu alloy was severely deformed by multidirectional forging (MDF) at 360-510°C, followed by solution treatment and T8 aging treatment.
Abstract: In this study, an age-hardenable 2219 Al–Cu alloy was severely deformed by multidirectional forging (MDF) at 360–510 °C, followed by solution treatment and T8 aging treatment. The evolution of the second-phase Al2Cu particles and the mechanical properties of the T8-aged samples were examined. The results indicated that a higher volume fraction and a more disperse distribution of the fragmented coarse particles were obtained for the sample deformed at low temperatures. The fragmented coarse particles were still difficult to sufficiently dissolve in the Al matrix in the subsequent solution treatment and could act as crack initiation sites, thereby reducing the mechanical properties of the alloy. With increasing the temperature of MDF, the number of coarse particles was gradually decreased, and the particles exhibited a more spheroidized shape after MDF. Correspondingly, more Cu atoms were dissolved in the Al matrix in the subsequent solution treatment, and the uniformity and density of the precipitates after T8 aging were improved. Thus, the mechanical properties of the T8-aged forgings were improved with increasing the temperature of MDF. The optimal mechanical properties were obtained when the deformation temperature was 510 °C, with ultimate tensile strength of 431.2 MPa, yield strength of 341.3 MPa, and elongation of 6.5% at room temperature.

63 citations

Journal ArticleDOI
TL;DR: In this article, optical microscopy and scanning electronic microscopy (SEM) were employed to observe the cavities and topography during the superplastic deformation of AZ31 alloy, respectively.

61 citations

Journal ArticleDOI
TL;DR: In this paper, an improved ring manufacturing process was proposed for the large 2219 Al alloy rings used to connect propellant tank components of a satellite launch vehicle to each other, and the results showed that the improved process can successfully be applied to manufacture the large 2D alloy rings without formation of macroscopic defects, resulting in a product with fine and uniform grains.

51 citations