Effects of Mechanical Stirring and Vibration on the Microstructure of Hypereutectic Al-Si-Cu-Mg Alloy Billets

Takagi, Hidetoshi; Uetani, Yasuhiro; Dohi, Masayoshi; Yamashita, Tomokazu; Matsuda, Kenji; Ikeno, Susumu

doi:10.2320/matertrans.48.960

Cited by 15 publications

(6 citation statements)

References 3 publications

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“…Figures 1(c), (d), (e) and (f) show that the stirring with or without the addition of graphene nanoplatelets can significantly affect the primary Si particle shape, size and distribution. It is well known that the use of mechanical stirring in semi-solid state can strongly promote refinement of the nondendritic structure due to the fragmentation of the primary Si crystals during semi-solid processing [25]. In current research work, the mechanical stirring resulted in a well refined microstructure.…”

Section: Resultsmentioning

confidence: 76%

Microscopical Characterization of Cast Hypereutectic Al-Si Alloys Reinforced with Graphene Nanosheets

Alghamdi

Ramadan

Halim

et al. 2018

Eng. Technol. Appl. Sci. Res.

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This paper illustrates the effects of stirring and graphene nanosheet (GNS) addition on the microstructure and mechanical behaviour of 393 hypereutectic Al-Si alloys used in the diesel engine pistons. Two processing routes were applied to fabricate hypereutectic Al-Si alloys: The first route mainly depends on stirring Al-Si alloys for 12 minutes at 400 rpm. The second one involves stirring Al-Si alloys for 2 minutes and then adding graphene nanosheets into the vortex, and consequently continue stirring for 10 minutes at 400 rpm. Results show that the distribution of the primary silicon was improved significantly in stir casting at both the edge and the center of the samples with relative reduction of 34% and 37% in the average particle size respectively. This average primary silicon size was further reduced by 17% with the addition of 1 wt% GNSs. GNS embedding into Al-Si alloy matrix resulted in remarkable increase in hardness values of the nanocomposites compared to the cast alloy.

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Section: Resultsmentioning

confidence: 76%

Microscopical Characterization of Cast Hypereutectic Al-Si Alloys Reinforced with Graphene Nanosheets

Alghamdi

Ramadan

Halim

et al. 2018

Eng. Technol. Appl. Sci. Res.

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“…Regarding the general similarity between the size and morphology of Si P particles in Zn-40Al-2Cu and hypereutectic Al-Si alloys, different techniques can be used to modify the shape and distribution of Si P particles in the microstructure of Zn-40Al-2Cu alloy, the most important of which are heat treatment [4], rapid solidification [5,6], mechanical/thermo-mechanical processing [7][8][9], chemical modification [4,[10][11][12], and molten metal processing [13][14][15]. Some techniques are cost-intensive and need special equipment.…”

Section: Introductionmentioning

confidence: 99%

Tribology of Si-rich TIG-deposited coatings on Zn–40Al–2Cu alloy

Rajabi

Taghiabadi

Shaeri

2020

Surface Engineering

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The effect of Zn-40Al-2Cu-xSi (x = 4 and 8 wt-%) tungsten inert gas (TIG) surfaced coatings and multi-pass friction stir processing (FSP) on the tribological properties of Zn-40Al-2Cu alloy was studied. The coatings had a well-modified microstructure comprising of finely dispersed primary Si particles (Si P ). These particles act as in-situ reinforcements, improving coating resistance against the friction-induced strains applied during sliding wear. The results of dry sliding wear showed that, at the applied pressures of 0.25, 0.5, and 0.75 MPa, the wear resistance of 4-pass FSPed coatings containing 4 wt-% Si is higher than that of the base alloy by 27, 47, and 57%, respectively. This can be attributed to the substrate strengthening and formation of compacted tribolayers on the surface of FSPed samples.

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“…Research interests are also centered on mechanical, electromagnetic and ultrasonic melt treatment techniques used to modify the primary Si crystals as well as other structural constituents. [3,[17][18][19] Powder metallurgy offered an alternative method to achieve satisfactory refinement of the primary Si crystals. However, due to its prohibitive cost, powder metallurgy is used only for selected applications.…”

Section: Introductionmentioning

confidence: 99%

In Situ Study of Microstructure Evolution in Solidification of Hypereutectic Al-Si Alloys with Application of Thermal Analysis and Neutron Diffraction

Sediako¹,

Kasprzak

2015

Metall Mater Trans A

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Understanding of the kinetics of solid-phase evolution in solidification of hypereutectic aluminum alloys is a key to control their as-cast microstructure and resultant mechanical properties, and in turn, to enhance the service characteristics of actual components. This study was performed to evaluate the solidification kinetics for three P-modified hypereutectic Al-19 pct Si alloys: namely, Al-Si binary alloy and with the subsequent addition of 2.8 pct Cu and 2.8 pct Cu + 0.7 pct Mg. Metallurgical evaluation included thermodynamic calculations of the solidification process using the FactSageä 6.2 software package, as well as experimental thermal analysis, and in situ neutron diffraction. The study revealed kinetics of solid a-Al, solid Si, Al 2 Cu, and Mg 2 Si evolution, as well as the individual effects of Cu and Mg alloying additions on the solidification path of the Al-Si system. Various techniques applied in this study resulted in some discrepancies in the results. For example, the FactSage computations, in general, resulted in 281 K to 286 K (8°C to 13°C) higher Al-Si eutectic temperatures than the ones recorded in the thermal analysis, which are also~278 K (~5°C) higher than those observed in the in situ neutron diffraction. None of the techniques can provide a definite value for the solidus temperature, as this is affected by the chosen calculation path [283 K to 303 K (10°C to 30°C) higher for equilibrium solidification vs non-equilibrium] for the FactSage analysis; and further complicated by evolution of secondary Al-Cu and Mg-Si phases that commenced at the end of solidification. An explanation of the discrepancies observed and complications associated with every technique applied is offered in the paper.

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Effects of Mechanical Stirring and Vibration on the Microstructure of Hypereutectic Al-Si-Cu-Mg Alloy Billets

Cited by 15 publications

References 3 publications

Microscopical Characterization of Cast Hypereutectic Al-Si Alloys Reinforced with Graphene Nanosheets

Microscopical Characterization of Cast Hypereutectic Al-Si Alloys Reinforced with Graphene Nanosheets

Tribology of Si-rich TIG-deposited coatings on Zn–40Al–2Cu alloy

In Situ Study of Microstructure Evolution in Solidification of Hypereutectic Al-Si Alloys with Application of Thermal Analysis and Neutron Diffraction

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