Effect of Eutectic Si Particle Morphology on ECAP Formability and Mechanical Properties of AC4CH Aluminum Casting Alloys

Al-Si alloys are the most important group among aluminum casting alloys. They are widely used in automotive and aerospace industries. Chemical modification of the Al-Si alloys leads to formation of fine, fibrous Al-Si eutectic mixture ensuring high mechanical properties. The modification is however known to increase the alloy porosity, which may, in turn, result in decrease of its properties. The following paper presents results of the research on quantitative description of the Al-Si cast alloys porosity and influence of Na modification on the porosity of AlSi9Mg alloy. Porosity in the hypoeutectic Al-Si alloys occurs in four types: shrinkage cavities, shrinkage porosity, isolated gas pores and gas pores surrounded by shrinkage porosity. Na modification leads to increase of shrinkage pores volume fraction.

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Investigation on Double Oxide Film Initiated Pore Formation in Aluminum Casting Alloys

International Journal of Engineering and Management Sciences ◽

10.21791/ijems.2020.2.18. ◽

2020 ◽

Vol 5 (2) ◽

pp. 141-153

Author(s):

Gábor Gyarmati ◽

György Fegyverneki ◽

Mónika Tokár ◽

Tamás Mende

Keyword(s):

Pore Formation ◽

Oxide Films ◽

Aluminum Casting ◽

Reduced Pressure ◽

Double Oxide ◽

Casting Alloys ◽

Eutectic Si ◽

X Ray Computed ◽

The Relationship

The most common, and in fact, the most deleterious defects of aluminum casting alloys are the so-called double oxide films or bifilms, which have a central role in porosity formation, as they can easily unfurl and inflate into pores during the solidification of the alloys. Sr addition is generally used in the foundry industry for the modification of the eutectic Si phase of hypoeutectic Al-Si alloys. However, Sr microalloying usually leads to an increased pore formation tendency. As bifilms are preferred sites for pore formation, it should be expected that Sr additions have a significant effect on the number and/or the structure of double oxide films present in the melt. In this work, the relationship between Sr-concentration and the susceptibility to pore formation has been investigated through the evaluation of melt quality of melts which had different levels of Sr. The bifilm content of the melts was investigated by the analysis of K-mold specimens and X-ray computed tomography (CT) of reduced pressure test (RPT) samples. It was found that liquid alloys with a higher Sr concentration had a significantly greater tendency to pore formation, which can be explained by the presence of a larger number of bifilm defects in the liquid alloy.

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Influence of Solution Temperature and Time on Microstructure and Properties of A357 Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.399-401.2195 ◽

2011 ◽

Vol 399-401 ◽

pp. 2195-2198

Author(s):

Yang Li ◽

Hai Feng Cheng ◽

Jian Min Zeng ◽

Yu Lin Zheng

Keyword(s):

Mechanical Properties ◽

Optimal Solution ◽

Solution Temperature ◽

Metallographic Analysis ◽

A357 Alloy ◽

Heat Temperature ◽

Casting Alloys ◽

Eutectic Si ◽

Solution Parameters ◽

And Diffusion

Metallographic analysis, hardness testing and diffusion kinetics analysis were used to investigate the influences of temperature and time on morphology of eutectic Si and properties of A357 alloy under the solution heat treatment, and optimal solution parameters were determined. The results indicate that solution heat temperature strongly influences the morphology of eutectic Si and mechanical properties of the A357 casting alloys. Spheroidization degree of eutectic Si decreases and the mechanical properties of A357 alloy with the increasing of solution temperature. According to the experiment results, optimal solution parameters of A357 alloy were determined as 550°C×6h.

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APEX TERNALLOY 6

Alloy Digest ◽

10.31399/asm.ad.al0277 ◽

1987 ◽

Vol 36 (2) ◽

Keyword(s):

Mechanical Properties ◽

Corrosion Resistance ◽

Physical Properties ◽

Surface Treatment ◽

Tensile Properties ◽

High Resistance ◽

Room Temperature ◽

Heat Treating ◽

Aluminum Casting ◽

Casting Alloys

Abstract APEX TERNALLOY 6 is one of a family of three APEX aluminum casting alloys (See APEX TERNALLOY 5, A1-273, November 1986.). It can be hardened by aging at room temperature and offers high mechanical properties. It has good castability, excellent machinability and high resistance to corrosion. Its many uses include aircraft components, gears, machinery parts, fittings, valves and ornamental products. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, machining, joining, and surface treatment. Filing Code: Al-277. Producer or source: Apex International Alloys Inc..

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