Study the Effect of Wetting between Fly Ash – Aluminum Alloy on Wear Resistance of Composites

Study the Effect of Wetting between Fly Ash – Aluminum Alloy on Wear Resistance of Composites

Presenter ： Liang Ging. Fan

Author ： Shueiwan H. Juang, Liang Ging. Fan, Shao Jun. Gu

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Fly Ash

Properties Class F Class C

(SiO2)+(Al2O3)+(Fe2O3), min, % 70.0 50.0

(SO3), max, % 5.0 5.0

Moisture Content, max, % 3.0 3.0

Loss on ignition, max, % 6.0 6.0

ASTM C618 、 CNS 3036

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Chemical Reactions

3232

322

OAlFe2O2FeAl2

OAlSi2

3SiO

2

32Al

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Aluminum—Fly Ash, ALFA

Al Cu Fe Mg Mn Ni Si Sn Zn

other 1.5-3.5 <1.30 <0.30 0.50 9.6~12.0 9.6~12.0 <0.20 <1.00

SiO2 Al2O3 Fe2O3 CaO MgO K2O Na2O SO3

52.73 26.87 5.11 - - - - 0.39

Chemical composition of fly ash （ wt% ）

Chemical composition of ADC12 Al alloy （ wt% )

• JIS designation, ADC12, was selected as the base metal.

• Fly ash was gotten from Mailiao power plant (Taiwan) and its density is ranged about 2.0~2.5 (g/cm3).

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SEM — Micrographs of Fly ash

(a) (b)

SEM micrograph showing (a) a complete particle of fly ash and (b) rough surface appeared on some particles.

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Wetting

solid

liquid

lyslsvSC

SC ： Spreading Coefficient γ ： Interfacial Energy Θ ： contact angle Al matrix

porosity

fly ash

SEM micrograph of ALFA composite.

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Experimental Procedure

Pre-treatment of fly ash

Mixing with stirring

Gravity casting

Property Measurement of composite castings

Wetting evaluation

yes

no

Start

End

Matrix metal

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Influence Factors of Fly Ash on Process

• Particle characteristics Density, size, shape and volume fraction

• Etch cleaning Remove the adsorbed contaminants

• Pre-heated Degas, de-moisture

clean fly ash.

untreated

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Optical Micrographs of False ALFA

Si

Al-Si

fly ash clusterAl matrix

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Experiment Design • Matrix: Aluminum alloys, ADC 12

• Addition: 3wt% Mg into the liquid metal to reduce the surface tension.

• Fly ash being pickled by sulfuric acid and pre-heated at 700 ℃ for a specified period, added into the aluminum melt at 850 ℃ with different weight percentage, such as 0wt%, 2wt%, 4wt%, 6wt%, 8wt% and 10wt%, and followed by mechanical stirring with 500 rpm to obtain a well-mixed melt.

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Optical Micrographs of Accepted ALFA

Micrograph of ALFA composites formed by gravity casting: (a) a complete particle and (b) uniform distribution of fly ash particles.

(a) (b)

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Density Measurements ADC12 ： 2.68 g/cm3

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Wear Tests• Wear behavior of ALFA composites tested using Pin-On-Disc

apparatus under a load of 9.8N and 18.6N at a constant sliding velocity of 0.5 m/s and sliding distance is 50 m.

• Counterpart material used in the wear tests was Cr steel ball with ¼ in. in diameter and HRC 58 in hardness.

abrasion tester

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Wear Tests

Load ： 9.8 N Load ： 18.6 N

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Conclusions• The test results revealed that the density of composites was decreased with

increasing fly ash percentage.

• Wear resistance of composites was improved as increasing fly ash percentage.

• Pretreatment of fly ash is the key to obtain a successful ALFA composite.

• In future, the die casting process will be introduced by virtue of runner passive stirring (RPS) to obtain a uniform distribution of fly ash inside metal matrix and a better structure by casting pressure.

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Thanks !!