MEEN 3344 –001 Material Science

MEEN 3344 –001
Spring 2003 EXAM 2
Material Science
Name (1) _______________________________
Closed book, calculator, and brain. Budget your time!
Definitions: (10 terms, each definition is worth 1.5 points, 15 total)
Match each term up with it’s definition, note that some definitions may match more than one
term, and there will be more definitions than terms.
1. Martensite ______
2. IT or TTT chart ______
3. Eutectic ______
4. Ductility ______
5. Stainless steel ______
6. Carburizing ______
7. Recrystallization ______
8. Strain hardening ______
9. Fatigue Limit ________
10. Welding _______
A. A hardening method, based on
movement of carbon through the
B. A measure of a material’s ability to
permanently deform without
C. When dislocation density impedes further
dislocation movement.
D. Pounding on a metal until it breaks.
E. An alloy that doesn’t follow the HumeRothery rules.
F. An isotherm in the phase diagram
G. A factor which relates how much a material
will stretch to it’s strength.
H. A chart that was created through numerous
non-equilibrium cooling tests, where crystal
structure is determined.
I. When increasing the number of cycles at a
constant load does not tend to cause failure.
J. A hard BCT material that resists indentation.
K. A high-temperature joining of two parts by
melting them or adding filler material.
L. None of the above.
Short Answers: (4 points each, 24 total)
11. All of the following statements about fracture are correct, except (may be more than 1):
a) Crack size does not affect fracture
b) ductile fracture produces a cup and cone fracture
c) in a brittle fracture there is measurable necking
d) fatigue and corrosion can accelerate fracture
12. What material is considered the more expensive cousin to steel? Why?
13. All of the following statements regarding metal fatigue are correct, except:
a) surface roughness decreases fatigue life.
b) A cold-worked specimen will fail sooner.
c) carburizing treatment can improve fatigue life.
d) a fatigue endurance limit is observed in pure aluminum.
14. What properties do we get from a Jominy end-quench test?
15. Name 2 differences between steel and cast iron.
16. What is the difference between brass and bronze? Give an example where brass is used.
17. (5) Given the phase diagram below, calculate the approximate weight % of austenite and
cementite in an iron/steel
with 2% carbon at 1000° C.
Show both calculations.
18. (5) Given the IT/TTT chart below, Draw your answer.
A) Give a heat-treatment that will produce a steel bar that is 50% fine pearlite, 25% fine bainite,
and 25% martensite.
B) If I want to take the above heat-treated steel, and transform it into 100% coarse pearlite, what
should I do. Draw or write any conclusions below. Remember that time can’t be stopped.
Exam 2 Spring 2003
Name _______________________
Open Book exam: (3 questions, 15 points each)
You are allowed to use your book, a calculator, one 8½ x 11 sheet of paper, but no neighbor.
Please be neat, and substantiate your answers as needed with references such as page or figure
numbers. Use only material from chapters 7 through 11.
1. (15) Make a table and discuss the relative merits of welding, brazing and soldering. Discuss
where each is useful, materials used, or used on, advantages and disadvantages.
2. (15) Suppose one had 3 specimens, one a cast iron of your choice, a beryllium/copper alloy,
and a steel with a eutectoid composition (.76% carbon). You want each to have as high a tensile
strength as possible, yet have reasonable ductility.
a) What cast iron would you pick and why?
b) What type of hardening or heat-treatment process would you use for each and why?
c) What is a reasonable amount of ductility?
(remember you have limited time, so concentrate on the main points first)
3. (15) You are to design a shear pin that will fail when a shear load of 300 lbs is applied to it.
a) Pick a suitable material, and based on your calculations, give a diameter for the pin.
b) Discuss why you picked that material.
c) Are there any suitable alternatives? Discuss briefly.
4. (5) General Questions, detach from test, all will get 5 free points
MEEN 3344 Spring 2003
Check the box that you most agree with.
The teacher treats all students
the same.
The instructor wants the
students to learn the material
The lectures are interesting
and useful
This course will be useful as
a practicing engineer.
The computer projector is an
effective tool in teaching this
The student presentations are
interesting and useful.
I studied harder so that I will
not have to take the final.