Grain size effects in aluminum processed by severe plastic deformation

Koizumi, Takayuki; Kuroda, Mitsutoshi

doi:10.1016/j.msea.2017.10.077

Cited by 73 publications

(26 citation statements)

References 45 publications

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“…Metallic micro-and nano-materials have excellent physical properties and unique geometrical features; thus, it is expected that these small-scale materials will be very important elements in future materials systems. The validity of the Hall-Petch relation, which describes the relationship between the yield strength of a metal or alloy and its grain size, has been verified for various kinds of metals through experiment 1)- 15) and analysis [16][17][18][19] . Related to this, the abovementioned small-scale materials show higher strength compared with their bulk counterparts due to the fine crystal grain structure, and therefore, it is expected that these materials will be used as high strength components in future advanced materials systems.…”

Section: Introductionmentioning

confidence: 94%

The Mechanical Properties of Polycrystalline Cu Microwires Having the Crystal Grains Grown by Joule Heating

Tohmyoh

Fukuda

Kimura

2019

J. Soc. Mat. Sci., Japan

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This paper reports on the relationship between the mechanical properties and the grain size of Cu microwires modified by Joule heating. The increase in yield strength as the grain size of a metal or alloy decreases is known as the Hall-Petch relation. Because the crystal grain size in thin metallic wires is fine, these have higher strength compared to their bulk counterparts. To improve the formability of 25 m-thick Cu microwires, the wires were heat-treated at various temperatures by Joule heating, and the grain size of the wires was evaluated quantitatively by cross section method. Larger crystal grains grew at higher temperatures, and the wire heat-treated at the highest temperature of 600 o C had a bamboo structure, in which the grain boundaries were only in the radial direction of the wire. Small-span, three-point bending tests were performed on the heat-treated Cu microwires to determine their mechanical properties. The Young's modulus of the wires was found to be independent of grain size, with an average value of 86.4 ± 2.4 GPa. On the other hand, the yield stress of the wires clearly depended on the grain size. The yield stress of a Cu microwire that had not been subjected to Joule heating was 311 MPa, and this decreased to 75 MPa after heat treatment at 600 o C. Finally, we confirmed that the Hall-Petch relation was applicable to the Cu microwires, except for those that, due to insufficient heat treatment, had crystal grain structures in which the grains were highly elongated in the axial direction of the wire.

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Section: Introductionmentioning

confidence: 94%

The Mechanical Properties of Polycrystalline Cu Microwires Having the Crystal Grains Grown by Joule Heating

Tohmyoh

Fukuda

Kimura

2019

J. Soc. Mat. Sci., Japan

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“…[7][8][9][10] The main ones include properties such as tensile strength, yield strength under tension or compression, hardness, microhardness, corrosion resistance, and others. 11,12 The most developed methods of implementing SPD are the ECAP and high-pressure torsion. To implement the ECAP, a tool with a 90-150°angle is used.…”

Section: Introductionmentioning

confidence: 99%

ECAP-treated aluminium alloy AA2030: microstructure and mechanical properties

Andreyachshenko¹,

Isheva²,

Mazhit³

et al. 2019

Mater. Tehnol.

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The work deals with the effect of the ECAP treatment on the microstructure and mechanical properties of the AA2030 alloy. There were four cycles of deformation in the 105°-tool for pre-annealed samples, which ensured the preparation of an ultrafine-grained structure, both along the Bc route and along the C route. The average grain size after four cycles of ECAP was 420 nm for the samples treated along the Bc route and 380 nm for the samples treated along the C route. In the structure of the metal, there were inclusions of Al20Cu2Mn3, the q-phase and Al7Cu3Fe. After three cycles of the ECAP treatment, the alloy was hardened by 54 % along the Bc route and 60 % along the C route compared with the annealed condition. The overall increase in the microhardness was 138 % for the samples treated along the Bc route and 113 % for the samples treated along the C route. Because of prolonged aging, the number of dispersoids increased at room temperature, long rod-like inclusions transformed into more favourable short ones with a length of up to 150 nm, and partial dissolution of the q-phase was observed. After the aging, the grain boundaries were predominantly equilibrium, thin, without the moire contrast, and a rearrangement of dislocation walls into subgrain boundaries was found. In addition, after the prolonged natural aging, large grains with non-equilibrium boundaries fragmented into subgrains with sizes of 100-300 nm.

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“…In the ECAP process, most of the FEM analysis done to analyse the deformation behaviour and the strain behaviour on the materials [9,10]. This includes the effect of friction on the material movement [11], the type of material used [12][13][14], the effect of using back pressure to the process [15], and the strain localisation achieved in the sample under several parameters [16]. In recent years, there are FEM studies involving strain distribution and deformation distribution [17].…”

Section: Introductionmentioning

confidence: 99%

Finite Element Simulation of Equal Channel Angular Pressing: Effect of Die Angle and Number of Passes

Shri

Hassan

Zahari

et al. 2019

IJAME

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Equal channel angular pressing (ECAP) is one of the popular severe plastic deformation processes used to produce bulk nanostructured materials. The degree of homogeneity of nanostructured is affected by various die parameters. In this paper, the effect of internal die angle (ϕ) and number of passes (N) on the strain behaviour of Aluminium Alloy 6061 (AA6061) during ECAP was investigated by using three-dimensional finite element analysis. The effect of number of passes and die angle on the homogeneity within the workpiece was analysed in terms of contours, radial view contour and inhomogeneity index. The analysis is done by comparing workpiece extruded up to 8 passes at die angle of 120° and 126°. It is observed that the resulting strain is higher at 120° die. However, the inhomogeneity index is decreasing in a similar pattern in both dies. The simulation results shed some lights on the optimum design of ECAP die for homogeneous microstructure.

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Grain size effects in aluminum processed by severe plastic deformation

Cited by 73 publications

References 45 publications

The Mechanical Properties of Polycrystalline Cu Microwires Having the Crystal Grains Grown by Joule Heating

The Mechanical Properties of Polycrystalline Cu Microwires Having the Crystal Grains Grown by Joule Heating

ECAP-treated aluminium alloy AA2030: microstructure and mechanical properties

Finite Element Simulation of Equal Channel Angular Pressing: Effect of Die Angle and Number of Passes

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