530.352 Final Exam 2003
Page 1 of 14
NAME:
________________________________
MATERIALS SELECTION
FALL SEMESTER
530.352
PROF. K.J. HEMKER
December 16
th
, 2003 :
FINAL EXAMINATION
(Closed book  closed notes  open mind)
1.
These questions are intended to demonstrate the broad understanding that you have about
material properties and from where they come.
Circle the following choices that make
these statements true.
(2 pts ea. / 50 pts total)
i)
The modulus of polymers are generally [ less than ;
about the same as
;
greater than
] the
modulus of ceramics?
ii)
Does the [101] direction lie in the (111) plane of a cubic crystal?
iii)
How many atoms are there per unit cell in an fcc metallic material? [ 1 ; 2 ; 3 ; 4 ; 5 ]
iv)
The yield strength of most pure metals is about [ the same
;
10X smaller
;
10X larger
;
1,000X smaller
; 1,000X larger ] than the theoretical strength of that material?
v)
Which is greater the [ compressive strength
;
fatigue strength
;
tensile strength
]
of a
ceramic material?
vi)
Which is greater the [ compressive strength
;
fatigue strength
;
tensile strength
]
of a
composite material?
vii)
In comparison with an engineering stress – engineering strain (Se) curve, the true stress –
true stress (
σ −ε
) curve for a compression test is
[ the same
;
shifted up and to the left
;
shifted down and to the right ]?
viii) The lattice friction (intrinsic resistance to dislocation motion) of a singlecrystalline sample
is higher for [ bcc or fcc ] metals?
ix)
If an alloy is overaged such that the distance between the precipitates increases by a factor
of 3, what would the strength be?
[ 1/9
th
; 1/3
rd
; same ; 3X ; 9X ]
x)
If an alloy is heattreated such that the grain size of the material increases by a factor of 9,
what would be the effect on strength [ 1/9
th
; 1/3
rd
; same ; 3X ; 9X ]?
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
530.352 Final Exam 2003
Page 2 of 14
xi)
Is ferrite (
α
iron) [ bcc, fcc or hcp ] at room temperature?
xii)
What is the major reason that alloying elements are added to steel? [ to strengthen through
precipitation hardening ; to soften through work softening ; to aide in the formation of
martensite ; to solid solution strengthen ]?
xiii) Of [stress intensity factor
;
fracture toughness ], which is a material parameter?
xiv) What are the units of stress intensity factor and fracture toughness? _______________
xv)
The activation energy for creep is equal to ___________
for a large number of metals?
xvi) Oxidation rates are usually either linear or parabolic.
Give
the equation for parabolic weight gain caused by oxidation. _______________________
xvii) The driving force for corrosion is generally measured in terms of potential voltage, which
metal is more likely to corrode [Fe – or
Zn] ?
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '08
 Hemker
 Materials Science, Tensile strength, Fracture mechanics

Click to edit the document details