Casting and Machinability of SiC Reinforced Al based Metal Matrix Composite

March 1, 2016

Undergraduate Thesis Presentation 2016

Author AKM Hashanur Rahman (1008006),

Md. Sohel Rana (1008022),Ranan Pratim Bhowal (1008026)

Supervisor Dr. Nikhil Ranjan Dhar

Professor

Department of Industrial and Production Engineering, BUET

Outline

Introduction Literature Review Gap Analysis Objectives Metal Preparation Quantitative Analysis Experimental Investigation Experiment Results Conclusion

Introduction

Metal matrix composite (MMC) is an advanced engineering material possessing numerous favorable characteristics like light weight, high strength, high stiffness, ability to be operated at elevated temperatures etc.

Metal matrix composites are widely used composite materials in aerospace, automobile, electronics and medical industries. This is because of their superior mechanical properties like strength to weight ratio and high thermal conductivity. The desired properties are mainly manipulated by matrix, the reinforcement element and the interface.

Literature Review

Kılıckap et al. investigated machining parameters on tool wear & surface roughness for 5% SiC-p Al-MMC.

Dabade et al. analyzed chip formation mechanism in machining of AMMC, using Taguchi method based experimentation.

Gallab et al. presented comprehensive tool wear models for Aluminium particulate MMC.

Literature Review

Shetty et al. applied Taguchi’s technique in machining of MMC. The method helps in proper selection of machining parameters.

Manna and Bhattacharya conducted studies using carbide tooling for machining of an Al/SiC composite.

Ozben et al. and Joshi et al. both machined an aluminum matrix reinforced with SiC particles and observed that the cutting speed was one of the dominant factors in limiting the machinability of the composite.

Gap Analysis

Most of the previous works have been done on 5wt%, 10wt% and 15wt% SiC reinforced Al based metal matrix composites.

Very few works have been done on tool wear and chip morphology on turning operation of 13wt% SiC reinforced Al.

There have been major difficulties on processing, casting and machining of 13wt% SiC reinforced Al.

Objectives

To fabricate a cylindrical bar of 13wt% SiC reinforced Al Metal Matrix Composite (MMC) by stir casting method.

Quantitative analysis of the composition of the casted cylindrical bar.

Determination of tool wear of uncoated carbide tool (SNMG) for different machining condition (dry and wet) of the bar.

Investigation on chip morphology on different cutting conditions (Dry and Wet)

Metal Preparation

Why 13wt% SiC reinforcement?

13wt% of SiC was reinforced into Aluminium because it holds the best mechanical properties of MMC.

From previous study it was found that more than 13wt% reinforcement of SiC has great hardness but decreasing aptitude of tensile strength and less than of 13wt% has higher tensile strength but lower hardness property.

So 500gm of SiC reinforced with 3850gm of Aluminium by stair casting covering the wt% of 13% and 87% respectively.

Mechanical Characteristics of Al-Sic MMC

High Tensile & Shear Moduli

Small Thermal Expansion Co-efficient

High Toughness & Ductility

Dimensional Stability & Good Moister Resistant

Good Wear Resistance

High Thermal & Electrical Conductivity

High Strength To Weight Ratio(3 Times ,More Than Steel)

Effective Load Carrying Capacity

Major Applications of Al-SiC MMC

In Automotive Industry:Passenger Car Brake Disk Disk Brake CalipersHigh Speed Rotating Shafts For Ships And Land Vehicles Valve Train & Piston Rod Piston And Piston PinDiesel Engine Piston Crankshaft Main BearingTire Stud And Drive Shaft

Major Applications of Al-SiC MMC

In Aerospace Industry:Aircraft Wheel And Brake Components For The

Military And Commercial Purpose

Space Shuttle Mid Fuselage Main Frame

Jet Engine Components

Hubble Space Telescope Antenna

Major Applications of Al-SiC MMC

In Electrical Industry:

Advanced Printed Circuit BoardMicroelectronic PackagingRadiofrequency And Microwave

PackagingSubstrates For Power Electronics Heat SpreadersHousings For Electronics Lids For Chips, E.G. Microprocessors.

Metal Preparation contd.

Stir Casting Process

One of the prominent and economical route for development and processing of metal matrix composites materials.

Properties of these materials depend upon many processing parameters and selection of matrix and reinforcements. Literature reveals that most of the researchers are using 7075 aluminum matrix reinforced with SiC particles for high strength properties whereas, insufficient information is available on reinforcement of "Al2O3" particles in 7075 aluminum matrix.

Melting of alloys Stir casting process

Mold pattern Casting process

Metal Preparation contd.

Final product with dimension (mm)

Quantitative Analysis

Sample : SiC_Al_Comp_IPEOperator : GCE, BUETComment : 20 deg/min , for MetalGroup: [Qual-Quant.] Std-Metal-IPE

Analyte Result

Al 84.2951 %

C 11.2262 %

Fe 1.7370 %

Si 1.4512 %

Na 0.3316 %

Cu 0.2433 %

Zn 0.2213 %

P 0.1568 %

S 0.1443 %

Ca 0.0734 %

Pb 0.0585 %

Cr 0.0244 %

Mn 0.0238 %

Ni 0.0131 %

Composition of the Bar

Quantitative Analysis contd.

Composition Analysis

Aluminium 84.2951% : As aluminium alloy is used instead of pure aluminium we get Fe, Na, Cu, Zn, P, S, Ca, Pb, Cr, Mn, Ni as extra material. So, the aluminium constitutes about 84.3% rather than 87%.

(C + Si) 12.6774% : Our target was to fabricate 13% SiC reinforcement but our bar constitutes 12.6774% which is very likely to attain desired mechanical properties and machinability.

Experimental Investigation

Procedure

Facing and Skinout : As the newly fabricated bar surface was rough, at first facing and skinout was imparted to get the smooth surface for further operation.

For facing and skinout operation high speed steel (tool size :120408) was used as cutting tool, cutting speed was 230rpm and 375rpm respectively and the feed rate was .15 mm/rev.

Turning : Main operation to determine the tool wear and chip morphology for machining the cylindrical bar. The turning operation was held under dry and wet condition for the certain period of time with interval. And then tool wear of the tool was measured by using an electron microscope and these process was repeated for certain amount of times.

Experimental Investigation contd.

Procedure

Tool wear is a time dependent process. As cutting proceeds, the amount of tool wear increases gradually. But tool wear must not be allowed to go beyond a certain limit in order to avoid tool failure.

Parameters, which affect the rate of tool wear are cutting parameters (cutting speed V, feed f, depth of cut d) cutting tool geometry (tool orthogonal rake angle) properties of work material Cutting conditions (dry or wet)

Tool: Uncoated Carbide (SNMG) Dimension: 4.76mm * 12.70 mm Grade: TP2220

Experimental Investigation contd.

Procedure

After taking all the data for comparing tool wear at different cutting condition the experiment was further progressed to determine the chip morphology.

With different cutting condition and parameters like depth of cut, feed rate and cutting speed all the data were collected to investigate the chip formation of the cylindrical bar.

For wet machining water soluble cutting fluid was used (1:8 volume cutting oil and water mixer )

Photographic View of the Experimental Setup

Turning operation on lathe machine Microscope for measuring tool wear

Photographic View of the Experimental Setup

Chip formation Cutting fluid Tool wear on the edge

Experimental Results

RPM Feed Rate (mm/rev)

Depth Of Cut (mm)

Time(Minute) Tool Wear (mm)

    0 0

    0.5 0.012

375 0.10 1.00 1 0.021

    2 0.03

    4 0.035

    7 0.04

    12 0.055

Table 1: Tool Wear VS Time for Dry Cutting (Turning)

Experimental Results contd.

Table 2: Tool Wear VS Time for Wet Cutting (Turning)

RPM Feed Rate (mm/rev)

Depth Of Cut (mm)

Time (Minute) Tool Wear (mm)

    0 0

    0.5 0

    1 0.001

375 0.01 1.00 2 0.008

    4 0.02

    7 0.028

    12 0.035

Experimental Results contd.

0 2 4 6 8 10 12 140

0.01

0.02

0.03

0.04

0.05

0.06

Tool Wear VS Time (Dry & Wet Cutting)

dry cutting wet cuttingTime(min)

Tool

Wea

r(mm

)

Experimental Results contd.

Irregular half nut shaped Chip formation for dry cutting (turning) Uniform half nut shaped Chip formation

during wet cutting (turning)

Experimental Results contd.

Collection of chips at different cutting condition

Experimental Results contd.

20 40 60 80 100 120 140 160 180 200 2200

0.5

1

1.5

2

2.5Chip Reduction Coefficient vs. Cutting Speed (dry machining)

feed 0.10 feed 0.13 feed 0.16

Cutting Speed, Vc (m/min)

Chi

p re

duct

ion

co-e

ffici

ent,ζ

Experimental Results contd.

0.09 0.1 0.11 0.12 0.13 0.14 0.15 0.16 0.170

0.5

1

1.5

2

2.5

Chip Reduction Coefficient vs. Feed Rate (dry machining)

Speed 130rpm Speed 230rpm Speed 375rpm Speed 590rpm

Feed Rate So (mm/rev)

Chi

p re

duct

ion

co-e

ffici

ent,ζ

Experimental Results contd.

20 40 60 80 100 120 140 160 180 200 2200

0.5

1

1.5

2

2.5

Chip reduction coefficient vs. cutting speed (wet cutting)

feed 0.10 feed 0.13 feed 0.16

Cutting Speed, Vc (m/min)

Chi

p re

duct

ion

co-e

ffici

ent,ζ

Experimental Results contd.

0.09 0.1 0.11 0.12 0.13 0.14 0.15 0.16 0.170

0.5

1

1.5

2

2.5

Chip reduction co-efficient, ζ vs feed rate(Wet cutting)

Speed 130rpm Speed 230rpm Speed 375rpm Speed 590rpm

Feed Rate So (mm/rev)

Chi

p re

duct

ion

co-e

ffici

ent,ζ

Conclusion

SiC reinforced Al based metal matrix composite has tremendous application on various sector on our modern days. It has great mechanical properties compared to any metal or alloy. With developed casting process and machinability it can be the major applicant to rule out the position of metal.