Unformatted text preview: Composites in which
Solution
Asceramics are used as the matrix is related to the slope of the bondforce curve at
shown in Equation 2.5–1, Young’s modulus material.
Figure 2.5–1 shows that the bondforce curve for
x0 .chemical vapor deposition (CVD) material A is steeper than that for material
A process by which
B (at the point for which F
0). Therefore, material A has a higher Young’s modulus. Since
two modulus is a chemically reacted to of the material, we should expect the beam
Young’s gases aremeasure of the inherent stiffness produce a thin
fabricated from material A to be stiffer and therefore deﬂect on than an identical of fabricated
coating of the reaction product, a solid, less the surface beam
from material B.
the workpiece.
.......................................................................................................................................
closepacked direction A crystallographic direction in
aAs discussed previously theatoms touch. is the derivative of the bondenergy
crystal along which bondforce curve
curve:
closepacked plane A crystallographic plane in a
2
crystal on which each atom contacts six neighbors.
U
U
F
F
and
(2.5–2)
x
x2
x
closepacked structures A crystal of a single atom
Combining Equations 2.5–1 and 2.5–2 yields are packed as tightly as
type in which the spherical atoms
2
possible, giving a coordination number of 12 and an APF
U
aE
(2.5–3)
of 0.74.2 HCP and FCC are closepacked structures.
x
coefﬁcient of of the bondenergy curve at is also proportional to Young’s
Thus, the curvaturethermal expansion t h x 0 Term deﬁned
modulus. Note that the smaller the radius of curvature, thestates the stiffness. A physical
higher that the
through the equation t h
t h T , which
interpretation of this relationship is that the steeper the sides of the energy well, the
coefﬁcient of thermal expansion is the atoms away from
greater the amount of energy required to displace theconstant that their equilibrium
relates
positions. thermal strain to changes in te...
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This note was uploaded on 02/25/2013 for the course PHYS 2202 taught by Professor Sowell during the Spring '10 term at Georgia Tech.
 Spring '10
 sowell
 Physics, Atom, The Crucible, ........., IRWIN / Schaffer

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