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Transcript of Metal Matrix Composites (MMCs) - improve.it Metal Matrix Composites (MMCs) Properties, Applications...
Metal Matrix Composites (MMCs)
Properties, Applications & Machining
6. Internationales IWF-Kolloquium18/19.04.2002, Egerkingen, CH
EMPA, Swiss Federal Laboratories for Materials Research and TestingDept. Materials TechnologyFeuerwerkerstrasse 39CH-3602 [email protected]
Olivier Beffort
structure of the talk
• introduction to MMCs
• typical properties of MMCs
• applications of MMCs
• machining of MMCs
• outlook - trends in R&D, market forecasts
sources: NASA & AFRL
ca. 1975
Space Shuttle - main cargo bay strutsmaterial: MMC - 6061/B/50ftotal weight saving: 145 kg (-44% vs Al)materials costs: > 1’000 US-$ / kg
source: VW
ca. 1999
VW-Lupo (Tdi) - rear brake drumsmaterial: MMC - A359/SiC/20pweight of drum: 1.55 kgmaterials costs: < 5 US-$ / kg
MMCs - materials with tailored properties ...
metals......... toughnessAl electrical & thermal conductivityMg heat resistance, "environmental stability"(Ti) processability
... by combination of metals and ceramics
ceramics..... Young’s Modulus, hardness, wear resistanceSiC strengthAl2O3 low coefficient of thermal expansionC, B4C (shape of ceramic: fibres, particles)
specific properties of metals and ceramics
Types of reinforcement for MMCsparticles and "foams"
particles (ceramics, carbon, ...)volume fraction: 5 - 75%size: 0.1 - 500 µm
"foams" (ceramics, graphite, ...)cearmic volume fraction: 20 - 90%pore size: 50 nm - 1 mm
short fibres (ceramics, carbon, ...)volume fraction: 10 - 30%size: ∅ : 1 - 6 µm, L: 10-500 µm
Types of reinforcement for MMCsfibres
100 �m
cont. fibres (ceramics, carbon, ...)volume fraction: 40 - 70%size: ∅ : 6-150 µm, L: ∞
structure of the talk
• introduction to MMCs
• typical properties of MMCs
• applications of MMCs
• machining of MMCs
• outlook - trends in R&D, market forecasts
particle reinforced MMCs
(PRM) vp: 5-75 %
• isotropic properties• high wear resistance• low density ............................................... 2.6 - 3.1 g/cm3
• high elastic modulus ............................... 90 - 300 GPa• high strength ............................................ 300 - 1000 MPa• good thermal conductivity ...................... 120 - 200 W/mK• low coeff. of thermal expansion (CTE) ... 7 - 20 10-6/K
fibre reinforced MMCs
(FRM) vf: 10-70 %
• anisotropic properties
• low density ........................ 1.8 - 3.2 g/cm3
• high strength ..................... 500 - 2000 MPa
• high elastic modulus ....... 120 � 300 GPa
• low CTE ............................. 0 - 10 10-6/K
• elevated temperature resistance (strength, fatigue, creep)
structure of the talk
• introduction to MMCs
•typical properties of MMCs
• applications of MMCs
• machining of MMCs
• outlook - trends in R&D, market forecasts
MMC brake discs & drums applications
MMC - type: AlSiMg/SiC/20-30ptrains (ICE) source:
Knorr Bremse
source: Lotus Cars Ltd.
VW LupoToyota RAV-4EVPlymouth ProwlerGM EV-1, Precept, ImpactFord ProdigyLotus Elise (1st series)race carts (various)....
source: Kolbenschmidt
automotive applications - engine
source: Honda
cylinder blocks and pistons(local reinforcement for wear and creep resist.)material: AlSi + short fibres and/or particlesPorsche 911, BoxsterToyota CelicaHonda Prelude, NSX, ...?
Toyota Celica
max rated voltage: VCE = 3300 VNominal current IC = 1200 A
50 mm
power conversion / electr. packaging applications
IGBT-modules (Insulated Gate Bipolar Transistor)
source: EUPEC
MMC - type:AlSi/SiC/70pCTE: 7-9 10-6/K
"thermal management applications"
structure of an IGBT-module
source: ABB Semiconductors
Si Si
Al2O3 or AlN Insulation
Si
Cu or Al Heats Spreader
Cooler
SolderCopper
Bond Wire
Grease 17 / 23.5
4.2
6.7 / 4.4
17 / 23.5Heat
CTE [ppm/K]CTE [ppm/K]
further MMC applications:
• racing, sports, leisure• cylinder liners, push rods, brake calipers, ...• spikes for racing shoes & tires, golf clubs, bicycle frames, ....
• aerospace applications• Space Shuttle - main cargo bay struts• Boeing 777 / Pratt & Whitney - fan exit guide vanes• Eurocopter - blade sleeves• F16 - ventral fins, fuel access door covers
• thermal and electric transportation• heat sinks, electronic packaging, ....• cooking ware• power transmission cables (electric conductors)
• robotics, linear technology, weaving machines, ........• military applications, .....
structure of the talk
• introduction to MMCs
• typical properties of MMCs
• applications of MMCs in transportation
• machining of MMCs
• outlook - trends in R&D, market forecasts
frequent statements concerning MMC machining
• MMC cannot be machined.................................... no !
• conventional tools cannot be used for MMCs.... yes !
• diamond tools are a must for MMC machining... yes !
• MMCs cannot be machined cost effectively........ no !
• MMCs are difficult to machine............................. yes !
why are MMCs difficult to machine ?
because of the relative hardness of the reinforcing materials
tool wear mechanisms occuring duringMMC machining
• abrasion due to hardness of reinforcement
• impact fatigue, break-outs
• PCD or CVD diamond tools are the best
• do not use CBN tools
• do not use HSS tools (not even coated ones)
• do not use un-coated WC/Co tools
tools suitable for MMC machining
influence of tool material on tool wear
0
0.1
0.2
0.3
0.4
0.5
0.6
0 2 4 6 8 10 12 14
time, [min]
flan
k w
ear
v B, [
mm
]
PKD, vc 500 m/min
WC/TiN, vc 150 m/min
MMC material: Al/Al2O3/20pvc: 500 m/minfeed: 0.4 mm/revDOC: 1.5 mmoperation: turning
source: Duralcan machining guidelines
parameters affecting machinability
the influencing parameters are :
machining performance or machinability isdefined in terms of tool life, material removal rateor surface quality of machined part
• MMC material - particle type, vol. fract, temper, ...
• tool - type and grade
• machining parameters - feed, speed, DOC
influence of MMC - reinforcement
the following characteristics decrease tool life:
• increasing particle volume fraction
• increasing particle size
• increasing particle hardness
• increasing aspect ratio of particles
influence of MMC - quality & temper
the following characteristics decrease tool life:
• defects (porosity, inclusions, segregations, ...)
• age hardening (peak aged condition T6)
influence of tool - type and grade
controversy - PCD or CVD diamond ???
for PCD tools, influence of diamond grain size:
• three common PCD grades: 2, 10 and 25 �m
• 25 �m best wear resistance; for roughing
• 2 �m best edge quality for finishing
roughing and finishing operations
for roughing coarse grained PCD (or CVD)and the most possible aggressive feed rateand depth of cut are recommended: besttool life performance
for finishing fine grained PCD or CVD andmoderate feed rate and depth of cut arerecommended: best surface finish quality
influence of machining parameters
the following characteristics increase tool life:
• high feed rate (< 0,5 mm/rev)
• high depth of cut (< 5 mm)
• medium cutting speed (300-500 m/min)
influence of feed rate on material removal
source: Duralcan machining guidelines
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0,1 0,2 0,4
feed rate, [mm/rev]
volu
me
rem
ove
d (
MM
C),
[cm
3 ]MMC material: Duralcan F3S.20Stool material: PCDvc : 300m/minDOC: 0.5 mmoperation: turning (stop @ 0.25 vB mm)
machining operations
• turning feasible, PCD or CVD diamond tools
• milling feasible, PCD or CVD diamond tools
• drilling difficult, PCD or CVD diamond tools
• tapping critical, CVD tools in development stagetap forming is an alternative to tap cutting
• sawing feasible, WC- or PCD tipped blades
• grinding feasible, diamond grinding
MMC machining cost issues - example
US-study concerning machining costs of brake rotors
PCD - tools cast iron rotor MMC rotorparts per day: 1900 3131
tool costs, $/day 402 2048
cost savings reference 0.15 $/rotor
CVD - tools
tool costs, $/day 568.75
MMC drilling cost issues - sp3 examples
Ford Motors Co.drilling 6.8 mm diam. holes 1.00´´ deep into Al/SiC/20pdrilling conditions: speed:1350 rpm, feed: 0.0075 ipr
WC/Co-drills: 1 - 2 holes per drill ⇒ $9 - $18 /holeCVD-drills: 330 holes per drill ⇒ $0.40 /hole
MSEdrilling 0.25´´ diam. holes into Al/SiC/20-48pWC/Co-drills: < 1 hole per drill
CVD-drills: >200 holes per drill ⇒ $0.52 /hole(cost of CVD drill: $115/drill
machining - conclusions
• recommended machiningguidelines should be respected
• only diamond tools should beused for machining MMCs
• an MMC with an ultrafine and low hardnessreinforcement is preferred
• except tapping, most common machiningoperations are possible
structure of the talk
• introduction to MMCs
• typical properties of MMCs
• applications of MMCs in transportation
• machining of MMCs
• outlook - trends in R&D, market forecasts
materials and process development - future
materials development• selectively reinforced structures• functional, adaptive materials• graded materials
process technology• "reactive" in-situ generation of MMCs• near net shape MMC processing technologies• low cost MMC processing technologies
machining• adapted tools (materials, coatings, geometries, ...) and lubricants• optimised machining parameters• alternative machining processes
MMC market forecasts 1999-2004
1600
3400
668
1000
137 161 152 220
0
500
1000
1500
2000
2500
3000
3500
ann
ual
MM
C w
orl
d m
arke
t, [
t]
groundtransportation
thermalmanagement
aerospace /defense
industrial /recreational equip.
1999
2004
market share: 62.2 %market share: 70.3 %AAGR: + 16.3 %
market share: 26.5 %market share: 21.9 %AAGR: + 9.8 %
market share: 5.4 %market share: 3.3 %AAGR: + 3.3 %
market share: 5.9 %market share: 4.5 %AAGR: + 7.7 %
source: BCC, USA
1999: 2.5 Mio kg, 103 Mio US-$2004: 4.9 Mio kg, 173 Mio US-$
http://mmc-assess.tuwien.ac.at
http://www.empathun.ch