Effects of cobalt and solidification cooling rate on intermetallic phases and tensile properties of a -Cu, -Zn, -Fe containing Al-Si alloy

Xavier, Marcella G. C.; Souza, Thaisa M. G.; Cheung, Noé; Garcia, Amauri; Spinelli, José Eduardo

doi:10.1007/s00170-020-05077-4

Cited by 10 publications

(2 citation statements)

References 29 publications

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“…They were manufactured from commercial pure elements (>99.7%), and characterized and tested in the "as-cast" conditions. The Co and Ni levels were chosen based on the suitable contents for the correction of Fe-contaminated Al alloys, as stated in the literature [15,18,19]. Two different processing methods were employed to induce distinct dendritic microstructure refinements: directional solidification (slow) and copper mold centrifugal casting (fast solidification).…”

Section: Methodsmentioning

confidence: 99%

Corrosion Resistance of Fe-Contaminated Al-Si-CU-Zn Alloys Modified With NI and Co and with Variable Secondary Dendrite Arm Spacing

Xavier¹,

Freitas²,

Koga³

et al. 2022

Preprint

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The corrosion behavior of Fe-containing directionally solidified (DS) and centrifugally cast (CC) Al-Si-Cu-Zn alloys with either Co or Ni additions has been investigated. Electrochemical and immersion corrosion methods were used to investigate the corrosion behavior in 0.6 M NaCl after short (1-hour) and long (30-day) exposure periods. The employed solidification methods allowed the production of samples with a wide range of secondary dendrite arm spacing (SDAS) while preserving Si and Fe-containing phases. The 0.5 wt.% Ni and Co additions led to the growth of the AlFeSi(Ni) and AlFeSi(Co) phases, but no binary AlNi nor AlCo intermetallic par-ticles have been generated. Potentiodynamic polarization studies at early exposure revealed an increase in the corrosion potential as the Ni was added for either fast or slow solidified samples. The electrochemical impedance spectroscopy at early exposure demonstrated that the Ni-modified alloy, on the other hand, was associated to smaller charge transfer resistances, in-dicating a reduction in corrosion resistance after short elapsed time into the electrolyte. Howev-er, 30-day immersion tests revealed much lower corrosion rate of the Ni-modified alloy than the other alloys, while the corrosion rates of the Co-modified and non-modified alloys were simi-lar. In the Ni-containing alloy, decreased corrosion rate under long-term corrosion process was attributed to the formation of a thick and dense alumina layer, effectively protecting the surface under such conditions. This work contributes to a better knowledge of the corrosion behavior of Ni- and Co-corrected Al industrial scrap compositions.

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Section: Methodsmentioning

confidence: 99%

Corrosion Resistance of Fe-Contaminated Al-Si-CU-Zn Alloys Modified With NI and Co and with Variable Secondary Dendrite Arm Spacing

Xavier¹,

Freitas²,

Koga³

et al. 2022

Preprint

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“…The experimental values of λL of the hypereutectic Zn-8 wt.%Al alloy that solidified under transient conditions were also shown to fit the classical eutectic growth law [20] with the expression λL = 0.35VE −1/2 and λL = 0.75 ṪE −1/4 . The increase in either cooling rate or growth rate induces a decrease in the microstructural spacing [57,58]. The primary dendritic arm spacing (λ1) as a function of solidification thermal parameters for the DS Zn-11wt.%Al alloy casting is depicted in Figure 16.…”

Section: Microstructural Growth and Correlation With Solidification T...mentioning

confidence: 99%

Hypereutectic Zn–Al Alloys: Microstructural Development under Unsteady-State Solidification Conditions, Eutectic Coupled Zone and Hardness

Septimio

Silva

Costa

et al. 2022

Metals

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The present study investigates the effects of Al content and solidification thermal parameters on the microstructural development under transient heat flow conditions for two hypereutectic Zn–Al alloys: Zn-6wt.%Al and Zn-11wt.%Al. The alloys were directionally solidified and had experimental cooling profiles monitored permitting cooling rates and growth rates to be determined along the length of the directionally solidified (DS) castings. The microstructure of the Zn-6wt.%Al alloy is shown to be formed by eutectic colonies, constituted by a eutectic mixture of (Zn) and (Al′) phases in the form of lamellae and the Zn-11wt.% Al alloy by the pro-eutectic (Al′) dendrites and the eutectic mixture in the interdendritic regions. Growth laws are experimentally determined relating eutectic and dendritic spacings to the growth rate and cooling rate. A diagram exhibiting the coupled zone of Zn–Al alloys as a function of cooling rate is proposed, which shows different microstructural morphologies influenced by composition and thermal parameters, that is, growth rate and the temperature gradient, synthesized by the cooling rate (Ṫ = G.V). The microhardness of both Zn-6wt.%Al and Zn-11wt.%Al alloys were shown not to depend on the length scale of the resulting microstructure.

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Investigations on metallurgical parameters in hypoeutectic Al–Si alloys under upward directional solidifications

Ferreira

Moura

Dantas

et al. 2022

Int J Adv Manuf Technol

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Effects of cobalt and solidification cooling rate on intermetallic phases and tensile properties of a -Cu, -Zn, -Fe containing Al-Si alloy

Cited by 10 publications

References 29 publications

Corrosion Resistance of Fe-Contaminated Al-Si-CU-Zn Alloys Modified With NI and Co and with Variable Secondary Dendrite Arm Spacing

Corrosion Resistance of Fe-Contaminated Al-Si-CU-Zn Alloys Modified With NI and Co and with Variable Secondary Dendrite Arm Spacing

Hypereutectic Zn–Al Alloys: Microstructural Development under Unsteady-State Solidification Conditions, Eutectic Coupled Zone and Hardness

Investigations on metallurgical parameters in hypoeutectic Al–Si alloys under upward directional solidifications

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