Microstructure evolution of AM60 magnesium alloy semisolid slurry prepared by new SIMA

Jiang, Jufu; Wang, Ying; Qu, Jianjun; Du, Zhiming; Sun, Yi; Luo, Shuyi

doi:10.1016/j.jallcom.2010.02.099

Cited by 56 publications

(25 citation statements)

References 22 publications

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“…On the other hand, some grains are clustered together (marked with arrow, A and B), possibly because that the grain boundary energy is less than twice the solid-liquid interfacial energy during the process of SSIT, and then these grains are interconnected by coalescence and form agglomerates. It was reported by Jiang et al 17) that the semi-solid alloy with large and irregular grains would have an adverse effect on the mechanical properties of nal parts. Therefore, the microstructures of starting material after SSIT are unsuitable for semi-solid forming.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, the grain re nement of alloys by different deformation methods has attracted much attention in recent years. Jiang et al 17) employed equal channel angular extrusion in SIMA to deform AM60 magnesium alloy. They found that high-quality semi-solid billet can be prepared by ve-pass equal channel angular extrusion and subsequent SSIT at 560 C for 15 min.…”

Section: Introductionmentioning

confidence: 99%

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Grain Refinement of Aluminum Alloy Bar by a Modified RAP Process for Semi-Solid Forming

2017

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A modi ed Recrystallization and Partial Melting (RAP) process including Radial Forging (RF) and Semi-Solid Isothermal Treatment (SSIT) was proposed to re ne the grains of 6063 Al alloy bar for semi-solid forming. The 6063 Al alloy bar (φ120 mm × 800 mm) was deformed by RF into a stepped shaft with different Area Reduction Ratios (ARRs) at the temperature of 300 C, and then the samples cut from both the central and peripheral parts of the RF-deformed bar were treated with SSIT at 630 C for 10 min. The effect of ARR on the microstructural evolution of semi-solid 6063 Al alloy was investigated. Results showed that, during the RF process, the microstructures of the samples became denser as the ARR increased. After SSIT, with the increase of ARR, the average grain sizes of both the central and peripheral parts were reduced and the spheroidization degrees of both the central and peripheral parts were improved. The variation tendency of grain size experienced three different stages: precipitous reduction, gentle reduction and unobvious change. Besides, the differences between grain sizes of the peripheral and central parts were gradually decreased with the increase of ARR. Additionally, the optimal process parameter for re ning grains was 70% ARR at 630 C for 10 min.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Grain Refinement of Aluminum Alloy Bar by a Modified RAP Process for Semi-Solid Forming

2017

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“…During heat treatment process of the specimens with adequate amount of predeformation, the solubility of the elements in α-Al increases and Al and Zn diffuse from the eutectic phase into α-Al, which makes the eutectic phase to dissolve, the second arms to combine and the α-Al to grow [10,18].Because the diffusion of the atoms along the grain boundary is faster than that inside the grains, concentrations of the solute at the primary α-Al and recrystallized grain boundary are higher. When the heat treatment temperature is higher than the eutectic temperature, the high concentration region begins to melt and liquid phases occur both at the grain boundaries and inside the grains [10,18,19].…”

Section: Liquid Fraction Versus Temperaturementioning

confidence: 99%

“…When the heat treatment temperature is higher than the eutectic temperature, the high concentration region begins to melt and liquid phases occur both at the grain boundaries and inside the grains [10,18,19]. The amount of the liquid increases and the grains separate from each other by increasing the temperature.…”

Section: Liquid Fraction Versus Temperaturementioning

confidence: 99%

Mechanical Properties and Microstructure Improvement of a Two-Step Strain Induced Melt Activation Processed 7075 Aluminum Alloy Compared to that SIMA Process

karamouz¹,

Alizadeh²,

Ahmadi³

2017

Preprint

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Strain induced melt activation process (SIMA) creates a globular microstructure which improves the hardness and ultimate tensile stress (UTS) of 7075 aluminum alloys. But, at the grain boundaries of SIMA processed 7075 aluminum alloy, presence of continuous and brittle intermetallic compounds and the eutectic structure result in decreasing mechanical properties, such as elongation, formability and etc. Hence, in order to improve microstructure and formability of 7075 aluminum alloy respect to SIMA process, a new process was done that is called two-step strain induced melt activation (TSSIMA). This process, which has been mentioned in the experimental procedure section, both organized globular structure and significantly modified the microstructure of the alloy compared to that of the SIMA method. It promoted discontinuity and more homogeneity in distribution of the precipitates and, approximately removed the eutectic mixture. Performing the rolling process on the alloy also revealed that it is more effective in formability enhancement in comparison with SIMA process. Also, it increased the hardness of 7075 aluminum alloy respect to that of SIMA process.

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“…Thixoforming, a typical method for the semi-solid processing of aluminum alloys, includes three procedures: semi-solid billet preparation, reheating and forming [1].…”

Section: Introductionmentioning

confidence: 99%

An Innovative Two-Stage Reheating Process for Wrought Aluminum Alloy During Thixoforming

Wang

Brabazon

Phillion

et al. 2015

Metall Mater Trans A

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An innovative two-stage reheating process has been developed to improve the thixotropic behavior of semi-solid wrought aluminum alloy during thixoforming. The variation of the microstructural evolution mechanisms with temperature and holding time during a traditional process and two-stage reheating process are investigated in this paper. A desirable semi-solid microstructure with spherical-like grains surrounded by a uniform liquid film is obtained in the two-stage reheating process. The semi-solid microstructure obtained via this two-stage reheating process has more refined equivalent diameters, a better spherical degree, a lower coarsening rate constant of solid grains and a reduced possibility of defects caused by entrapped liquid than that produced by the traditional reheating process. These results prove that the two-stage reheating process is a promising method for manufacturing wrought aluminum alloy during thixoforming.

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Microstructure evolution of AM60 magnesium alloy semisolid slurry prepared by new SIMA

Cited by 56 publications

References 22 publications

Grain Refinement of Aluminum Alloy Bar by a Modified RAP Process for Semi-Solid Forming

Grain Refinement of Aluminum Alloy Bar by a Modified RAP Process for Semi-Solid Forming

Mechanical Properties and Microstructure Improvement of a Two-Step Strain Induced Melt Activation Processed 7075 Aluminum Alloy Compared to that SIMA Process

An Innovative Two-Stage Reheating Process for Wrought Aluminum Alloy During Thixoforming

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