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ME363
HW7
Fall 2011
No due date
1.
The tensile strength of a part produced by powder metallurgy can be empirically related to
porosity as follows:
0
nP
UTS
UTS e
−
=
where
P
is the volume fraction of pores in solid, UTS
0
is the tensile strength at zero porosity,
and the exponent ranges between 4 and 7 (assume to be 4 in this case).
A fully dense
ceramic has the properties of UTS
0
=180 MPa, E
0
= 300 GPA and density of 4000 kg/m
3
.
(a)
After compaction, it reaches 70% of the density of the solid material.
If the linear shrinkage
is 5% during sintering, determine the density after sintering.
(b)
Determine the UTS and modulus of elasticity of this material after sintering.
2.
A ceramic has
k
0
= 0.8 W/mK.
If this ceramic is shaped into a cylinder with a porosity
distribution given by
( )( )
0.1
/
1
/
,
Px
L
x
=−
L
where
x
is the distance from one end of the
cylinder and
L
is the total length, plot the porosity as a function of distance, evaluate the
average porosity, and calculate the average thermal conductivity.
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This note was uploaded on 12/25/2011 for the course ME 300363 taught by Professor Staff during the Fall '10 term at Purdue UniversityWest Lafayette.
 Fall '10
 Staff

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