MMC Hammer
Group members:
Ed Barnard
Lizzie Hager
Jenny Lichter
Kevin McComber
2-26-04
Overview
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Goal
Material Properties
Centrifugal Casting Process
Short Term Objectives
Prototype Design and Mold
Progress
Upcoming Experiments
Goal
The goal of our project is to manufacture a
light-weight, high fracture toughness
hammer using metal matrix composites.
Halstead
Material Properties
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Conventional steel hammer:
Carpenter 20Cb-3® Stainless Steel
Density
9
MMC hammer:
SiC / Ti-6Al-4V, V(%)=35
SiC / 6061 Alum, V% = 0.48
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Important properties for a hammer:
 Density
 Tensile strength
 Modulus
 Wear resistance
 Fracture toughness
6
g/cc
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3
0
Steel
SiC / Ti-6Al-4V SiC / 6061 Alum
Material
Carpenter, Koczak p. 310
Material Properties
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Conventional steel hammer: Tensile measurements at RT
MMC hammer: Tensile measurements at 0° C
Tensile Strength, Ultimate
Modulus of Elasticity
2000
250
200
150
GPa
MPa
1500
1000
100
500
50
0
0
Steel
SiC / Ti-6Al-4V
Material
SiC / 6061 Alum
Steel
SiC / Ti-6Al-4V
SiC / 6061 Alum
Material
Carpenter, Koczak p. 310
Centrifugal Casting Process
Centrifugal Casting Process
Pressure Vessel Calculations
Pmax 
 UTS  r  ri 
2
o
2
o
2


2 
S.F .  r  ri 
Material
σUTS (ksi)
Pmax = 2200 psi = 150 atm
S. F. : safety factor = 2
ri : inner radius = 1 inch
Outer radius Outer radius
< σUTS >
(σUTS)min
Brass
30-90
1.08
1.16
Stainless steel
60-150
1.04
1.08
Aluminum
45-80
1.07
1.10
Graphite
7-10
1.77
2.09
Poco
Short Term Objectives
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Making mold
size
 stability
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Ceramic scaffold
packing
 formation
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"Home"
Prototype design
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Hammer head
simple design
 radially symmetric
(conical)
 More complex designs
can be implemented
later
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Prototype Mold
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Two-piece mold
Conical to aid in
the release
Sealed with an
O-ring and
bolted shut
Swagelok
connector to
runner
Prototype Mold
Top Mold
Progress
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Two ceramic layers per casting
Investigating interfaces
2µm TiC has been eliminated
Hardness tests
Upcoming Experiments
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Hardness test
SEM
Machine mold
Find an effective break-out ceramic for mold
release
Use and test new ceramic particles
Projected Work Schedule
2/5 2/12 2/19 2/26 3/4 3/11 3/18 3/25 4/1 4/8 4/15 4/22 4/29 5/6 5/13
Materials
Metal choice
Ceramics choice
Part production
CAD
Investment casting
Steel machined mold
Ceramic preform
Volume fraction
Size distribution
Time Permitting
"
Final testing
CODE:
Task
Sub-task
Gradation
Testing
Works Cited
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“Carpenter 20Cb-3® Stainless Steel, Bar.” Accessed 22 Feb 2004. MatWeb.com, The Online Materials
Database. 2004. <http://www.matweb.com/search/SpecificMaterialPrint.asp?bassnum=NCAR90 >.
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Halstead, Gary. “Pictures from Dictionaire Paisonné du Mobilier Français.” Accessed 24 February 2004.
Medieval and Renaissance Woodworking. 2003.
<http://www.medievalwoodworking.com/vld_tools.htm >.
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“Home > Centrifuges < Centrifuges, Floor > RFQ Form.” Accessed 23 Feb 2004. Used-Line.Com : Used HiTech and Scientific Equipment. <http://used-line.com/cgi-bin/used/~4055271_/IEC_CRU_5000.htm >.
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Koczak, et al. “Metal-Matrix Composites for Ground Vehicle, Aerospace and Industrial
Applications.” Fundamentals of Metal Matrix Composites. Boston: Butterworth-Heinemann, 1993.
Eds. Suresh, S., Mortensen, A. and A. Needleman. 297-326.
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“Poco Graphite AXM-5Q Specialty Graphite.” Accessed 25 Feb 2004. MatWeb.com, The
Online Materials Database. 2004.
<http://www.matweb.com/search/SpecificMaterialPrint.asp?bassnum=NCAR90 >.