Hardening Mechanisms of Metals and Alloys Produced by SPD

Hashimoto, Satoshi; Suzuki, Takuya; Vinogradov, Alexei

doi:10.4028/www.scientific.net/msf.503-504.967

Cited by 3 publications

(1 citation statement)

References 5 publications

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“…However, the observation in Figure 12 suggested that the hardness distribution of 120º sample was less homogenous compared to 126º, even though its average hardness is higher. Therefore, increasing the die angle can lead to a decrease in strain magnitude but the strain induced is more homogeneous throughout the samples [31].…”

Section: Effect Of Die Angle and Number Of Press To Peeqmentioning

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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Section: Effect Of Die Angle and Number Of Press To Peeqmentioning

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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Strategies for hardening purity metallic materials by high pressure and high temperature quenching method

Zhao,

Jiang,

Bao

et al. 2024

APL Materials

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Purity metallic materials are increasingly demanded in modern manufacturing industries, but their applications are limited owing to their poor wear resistance and mechanical properties. Therefore, exploring an efficient hardening method to significantly enhance the hardness of pure metals is emergent in materials science. In this work, a series of high pressure and high temperature (HPHT) quenching experiments were carried out on several pure metals, with a maximum hardening factor exceeding 10. The results indicated that pressure has an unusual effect on refining grains and increasing the Hall–Petch coefficient ky. The ky value of pure Fe is 49.5 GPa*μm1/2 with a quenching pressure of 5 GPa, which is two orders higher than that of the untreated polycrystalline sample (0.2 GPa*μm1/2). In addition, we report an extreme hardness of 8.34 GPa in pure Ti induced by HPHT quenching, and the unprecedented hardening comes from the formation of the twin and lath martensitic substructures. The hardening mechanism of the HPHT quenching method is a combination of Hall–Petch hardening and work-hardening. Our results provide a practical route to achieve attractive mechanical properties in pure metals and shine a light on the hardening mechanism of metallic materials.

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Rayleigh-like instability in the ion-shaping of Au–Ag alloy nanoparticles embedded within a silica matrix

Rizza¹,

Attouchi²,

Coulon³

et al. 2011

Nanotechnology

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We have studied how spherical 23 ± 3 nm Au(45)Ag(55) nanoparticles embedded within a silica matrix transform into prolate nanorods and nanowires by irradiating them with swift heavy ions. Samples were irradiated at room temperature and normal incidence with 74 MeV Kr and 36 MeV S ions for fluences up to 1.0 × 10(15) cm(-2). We demonstrate the existence of two regimes: (i) below a critical fluence, ∼ 2.0 × 10(14) cm(-2), the transformation of the spherical nanoparticle into a nanorod is an individual process, i.e. each nanoparticle transforms into a single nanorod; (ii) for larger fluences the transformation from nanorod to nanowire becomes a collective process, i.e. the break up and dissolution of unstable nanorods contribute to the growth of long nanowires. The passage from the first to the second regime can be interpreted in terms of a Rayleigh-like instability under irradiation. The latter becomes active when the diameter of the nanowire approaches its saturation width under irradiation. Furthermore, we show that the composition of the alloy is only slightly modified during the ion-shaping process. Finally, the energy and the fluence thresholds for deformation and the deformation strain-rate are estimated.

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Hardening Mechanisms of Metals and Alloys Produced by SPD

Cited by 3 publications

References 5 publications

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

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

Strategies for hardening purity metallic materials by high pressure and high temperature quenching method

Rayleigh-like instability in the ion-shaping of Au–Ag alloy nanoparticles embedded within a silica matrix

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