Evaluation of Al-5wt%Si-5wt%Zn as Raw Material for Semisolid Forming

Cecilia Tereza Weishaupt Proni; Leandro Cássio de Paula; Luis Torres; Eugênio José Zoqui

doi:10.4028/www.scientific.net/SSP.285.339

Paper Titles

Slurry Preparation and Hot Tearing Susceptibility of A201 Aluminum Alloy in Rheological Die Casting
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A Study on Bar Drawing Process of A356 Alloy in Semisolid State
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Metallurgical Interface of 7075/6061 Bimetallic Composite Ingot Casted by Semi-Solid Slurry and Molten Metal Pouring
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Development of Slurry Preparation Method by Applying Mechanical Vibration
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Evaluation of Al-5wt%Si-5wt%Zn as Raw Material for Semisolid Forming
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Modelling and Experimental Investgations of Tooling Issues for Thixoforming of Steel
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Study on Thixoforming Process of 15%SiCp/2A14 Composite for Production of Track Shoe
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Modelling Semi-Solid Behaviour and Brittle Temperature Range
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Using the Phase Field Method to Investigate Microstructural Evolution of Semi-Solid 357.0 Slurries
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HomeSolid State PhenomenaSolid State Phenomena Vol. 285Evaluation of Al-5wt%Si-5wt%Zn as Raw Material for...

Evaluation of Al-5wt%Si-5wt%Zn as Raw Material for Semisolid Forming

Abstract:

Designing new alloys for semisolid processing is key to the success of semisolid materials technology. While aluminium-silicon and aluminium-zinc alloys have been tested as potential raw materials, ternary aluminium alloys containing silicon and zinc have yet to be tested. As such alloys may exhibit the rheological behaviour required for semisolid forming and the excellent final mechanical properties of Al-Zn alloys, we investigated the thermodynamic aspects of the solid-liquid transition of Al-5.5wt%Si-5wt%Zn alloy, the morphological stability of this alloy in the semisolid temperature range and the corresponding rheological behaviour. Thermo-Calc^® simulation software was used to evaluate the solid-to-liquid transition and identify the semisolid temperature range within which the liquid-fraction sensitivity is low and the process is therefore controllable. Based on the results of the simulation, a target temperature of 588 °C was chosen. This is sufficient to produce a liquid fraction of 55 % and a corresponding liquid-fraction sensitivity (dfl/dT) of 0.009 C^-1. The Al-5wt%Si-5wt%Zn alloy was prepared by conventional casting in a refrigerated copper mould without grain refining, and the alloy was characterized to determine the stability of the microstructure after heating to 588 °C and holding at this temperature for holding times of 0, 30, 60, 90 and 120 s. The same temperature and holding times were used to evaluate the rheological behaviour in hot compression tests. A grain size of 170 μm, globule size of 100 μm and circularity of 0.6 were achieved, leading to a maximum apparent viscosity of 2 x 10⁵ Pa.s, which rapidly decreased to 3 x 10⁴ Pa.s after a shear rate of 9 s^-1 was reached.

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Periodical:

Solid State Phenomena (Volume 285)

Pages:

339-344

DOI:

https://doi.org/10.4028/www.scientific.net/SSP.285.339

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Online since:

January 2019

Authors:

Cecilia Tereza Weishaupt Proni*, Leandro Cássio de Paula, Luis Torres, Eugênio José Zoqui

Keywords:

Aluminium Alloys, Microstructure, Rheology, Semisolid Materials, Thixoforming

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