Halo formation of Zn-Al alloys under conventional solidification and intensive convection solidification

Yang, Wenchao; Fredriksson, Hasse; Ji, Shouxun

doi:10.1016/j.jallcom.2016.11.281

Cited by 8 publications

(2 citation statements)

References 21 publications

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“…The shape and the size of the dark areas varies with typical size of up to 50 μm. They are surrounded by Zn-rich halos with a width of <10 μm, characteristic for hypereutectic Zn-Al alloys (>5 wt.% Al) at low cooling rates (Bluni et al, 1995; Yang et al, 2017).…”

Section: Resultsmentioning

confidence: 99%

Influence of Al Alloying on the Electrochemical Behavior of Zn Electrodes for Zn–Air Batteries With Neutral Sodium Chloride Electrolyte

et al. 2019

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Zn alloy electrodes containing 10 wt. % Al were prepared to examine the applicability as anodes in primary Zn–air batteries with neutral 2M NaCl electrolyte. These electrodes were investigated by electrochemical measurements and microscopic techniques (SEM, LSM, AFM). Based on the cyclic voltammetry and intermediate term (24 h) discharge experiments, the only active element in the as-prepared alloy was found to be Zn. It was further confirmed by LSM that Zn rich areas dissolved while Al remained passive during discharge. The passive state of Al was also demonstrated by conductive AFM investigations on the as-cast alloy surfaces. The results on potentiodynamic polarization and weight loss measurements indicated that the alloy electrode was less prone to corrosion than pure Zn electrode. The electrochemical behavior of the electrodes was modified under certain cathodic polarization previous to measurements. Accordingly, originating from Al activation due to application of cathodic potentials, potentiodynamic polarization studies showed a clear shift on the corrosion potentials of the alloy toward more negative values. On the basis of these results, with the precondition of Al activation prior to discharge experiments, the effect of Al alloying on the Zn electrodes was revealed as temporarily enhanced potentials on the discharge profiles in comparison to pure Zn electrodes.

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Section: Resultsmentioning

confidence: 99%

Influence of Al Alloying on the Electrochemical Behavior of Zn Electrodes for Zn–Air Batteries With Neutral Sodium Chloride Electrolyte

et al. 2019

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“…In addition to its grain refinement effect, intensive melt shearing during solidification influences the thickness of the halo of the secondary phase formed on the primary phase particles. Experiments at a high shear rate [18] showed that the Zn-rich halos disappeared from the Al-rich phase during the primary solidification and the eutectic solidification of the Zn-Al alloys.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Effect of Simultaneous Melt Shearing and Cooling on Grain Formation and Rheology of A356 Aluminum Alloy

Ahmadein,

Alsaleh,

Elsayed

et al. 2023

Crystals

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Despite the dozens of earlier research verifications, the contribution of shearing of molten metallic alloys during their solidification to grain formation is still ambiguous. Also, modeling of this phenomenon has received very little attention. Experiments were conducted in this study to investigate the effect of the shear rate on the density, size, and shape factor of the formed grains up to a solid fraction of 0.15 for the solidifying A356 aluminum alloy in the coaxial cylinder viscometer. The rheology of the formed semisolid slurry was studied as well. Results exhibited morphological evolution and grain refinement. The grain number density increased from 5 × 108 m−3 in the absence of melt shearing to reach 4 × 109 m−3 at the shear rate of 250 s−1. Also, the shape factor was improved to reach 0.78. Based on the experimental investigations, the grain number density under shearing was correlated to the shear rate and the grain number density in the absence of shearing via an empirical formula. A shear-dependent grain multiplication factor was deduced. The alloy exhibited a shear-thinning behavior where the viscosity obeyed the power law with a constant and an exponent of 0.9264 and 0.468, respectively. Moreover, the measured data were fitted to several proposed viscosity models and the model of Hirai et al. showed the best fit; therefore, it was recommended for predicting the viscosity of semisolid slurries.

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Correlation between unsteady-state solidification thermal parameters and microstructural growth of Zn–8 mass% Al and Zn–8 mass% Al–XBi tribological alloys

Septimio

Costa

Silva

et al. 2019

J Therm Anal Calorim

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Halo formation of Zn-Al alloys under conventional solidification and intensive convection solidification

Cited by 8 publications

References 21 publications

Influence of Al Alloying on the Electrochemical Behavior of Zn Electrodes for Zn–Air Batteries With Neutral Sodium Chloride Electrolyte

Influence of Al Alloying on the Electrochemical Behavior of Zn Electrodes for Zn–Air Batteries With Neutral Sodium Chloride Electrolyte

Analysis of the Effect of Simultaneous Melt Shearing and Cooling on Grain Formation and Rheology of A356 Aluminum Alloy

Correlation between unsteady-state solidification thermal parameters and microstructural growth of Zn–8 mass% Al and Zn–8 mass% Al–XBi tribological alloys

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