Materials Final
2A The carbon content in an eutectoid steel is______
Ans: 0.76 wt%
3A The carbon content in an eutectic steel ____
Ans: 2.06-6.67 %
4d Lightweight bicycle frames
Ans: Aluminum
4e Cryogenic (i.e. very low temperature) container
Ans: Brass
4a The block of an an internal combustion engine. Where high wear resistance and good vibration damping properties are required.
Ans: Grey Cast Iron
4c High-temperature furnace elements to be ud=sed in oxidizing atmosphere... where high resistance to oxidation is required.
Ans: Platinum
4b Condensing heat exchange for steam... where corrosion resistance is important
Ans: Stainless Steel
14 A solid-solution alloy is a. Produced by melting two metals together that do not mix in the solid state b. An alloy of two solid phases c. Homogeneous and single phase at ordinary temperatures d. Quickly attacked by an acid
Ans: a
15 Plastically deforming a metal specimen near room temperature generally leads to which of the following property changes? a. An increased tensile strength and a decreased ductility b. A decreased tensile strength and an increased ductility c. An increased tensile strength and an increased ductility d. A decreased tensile strength and a decreased ductility
Ans: a
17 Impurity atoms in ceramic materials may form substitutional and interstitial solid solutions? a. True b. False
Ans: a
23 If engineering strain and true strain were measured simultaneously during a tensile test, which would have the higher value. a. Engineering strain b. True strain
Ans: a
26 Which one of the following types of stress strain relationship best describes the behavior of most metals at temperatures above their respective recrystallization points. a. Elastic and perfectly plastic b. Elastic and strain hardening c. Perfectly elastic d. None of the above
Ans: a
27 The transverse rupture strength is a property usually associated with which one of the following material types. a. Ceramics b. Metals c. Plastics d. Rubber
Ans: a
6 Hooke's Law defines which of the one of the following regions of the stress strain relationship for engineering materials a. Elastic region b. Plastic region c. Neither
Ans: a
29 Which of the following statements are NOT true ( may be more than 1 correct answer) a. Bending a paperclip into a permanent new shape is considered elastic deformation b. Typically, all calculations involving stress or strain use true strain. c. There is a strong correlation between hardness and tensile strength d. A safety factor for an airplane may change based on flight conditions
Ans: a,b,d
19 All of the following statement about fracture is correct, except (may be more than 1 right answer) a. Crack size does not affect Fracture b. Ductile fracture produces a cup and cone fracture c. In a brittle fracture there is a measurable neacking d. Fatigue and corrosion can accelerate fracture
Ans: a,c
12 Which of the following types of stress strain relationship best describes the behavior of most metals at room temperature a. Elastic and perfectly plastic b. Elastic and strain hardening c. Perfectly elastic d. None of the above
Ans: b
13 A brittle material typically exhibits substantial plastic deformation with high energy absorption before fracture a. True b. False
Ans: b
18 Plain carbon steels are designated in the AISI code system by which of the following? a. 01xx b. 10xx c. 11xx d. 12xx e. 30xx
Ans: b
20 Cup-and-Cone fracture is representative of a. Brittle fracture b. Ductile fracture c. Shear fracture d. Tensile fracture
Ans: b
22 If engineering stress and true stress were measured simultaneously during a tensile test, which would have the higher value. a. Engineering stress b. True stress
Ans: b
24 the plastic region of the stress-strain curve for a metal is characterized by a proportional relationship between stress and strain. a. True b. False
Ans: b
25 Which one of the following types of stress strain relationship best describes the behavior of most metals at room temperature a. Elastic and perfectly plastic b. Elastic and strain hardening c. Perfectly elastic d. None of the above
Ans: b
30 For non-crystalline ceramics, plastic deformation occurs by the motion of dislocations a. True b. False
Ans: b
7 Which one of the following materials has the highest modulus of elasticity a. Aluminum b. Diamond c. Steel d. Titanium e. Tungsten
Ans: b
10 Which of the following statements about crystal structures are true( may be more than 1 answer a. metals are almost never in a crystal form b. amorphous materials do not have long range order c. FCC and HCP materials, if made from the same atoms, would have the same density d. BCC and HCP have the same atomic packing factor
Ans: b, c
2 Ceramics are characterized by which two of the following bonding types (two correct answers)? a. Adhesive b. Covalent c. Hydrogen d. Ionic e. Metallic f. Van der Waals
Ans: b, d
3 Polymers are characterized by which two of the following bonding types (two correct answers)? a. Adhesive b. Covalent c. Hydrogen d. Ionic e. Metallic f. Van der Waals
Ans: b, f
#A use Fe-Fe3C diagram 1A A steel with 1% carbon is known as which one of the following a. Eutectoid b. Hypoeutectoid c. Hypereutectoid d. Wrought iron
Ans: c
11 Which of the following types of stress strain relationship best describes the behavior of brittle materials such as ceramics and thermosetting plastics a. Elastic and perfectly plastic b. Elastic and strain hardening c. Perfectly elastic d. None of the above
Ans: c
21 Which one of the following is the correct definition of ultimate tensile strength, as derived from the results of a tensile test on a metal specimen? a. The stress encountered when the stress-strain curve transforms from elastic to plastic behavior b. The maximum load divided by the final area of the specimen c. The maximum load divided by the original area of the specimen d. The stress observed when the specimen finally fails
Ans: c
4 Which one of the following crystal structures has the fewest slip directions and therefore the metals with this structure are generally more difficult to deform at room temperature? a. BCC b. FCC c. HCP
Ans: c
5 Hardness of metals is best defned as which one of the following. a. Energy absorbed by a material when an object strikes its surface b. Resistance to bending c. Resistance to permanent indentation d. Resistance to scratching
Ans: c
9 Which one of the following types of stress strain relationship best describes the behavior of brittle materials such as ceramics and thermosetting plastics a. elastic and perfectly plastic b. elastic and strain hardening c. perfectly elastic d. none of the above
Ans: c
16 Polymeric materials used in engineering today include synthetic materials and natural rubber. The three categories of polymers are _____. a. Cermets, Thermosets, and Elastosets b. Thermoplastics, cermets, and Elastosets c. Thermosetting Polymers, Elastomers, and Natural Rubber d. Thermoplastic Polymers, Thermosetting Polmers, and Elastomers
Ans: d
1 Metals are characterized by which of the following bond types a. Adhesive b. Covalent c. Hydrogen d. Ionic e. Metallic f. Van der Waals
Ans: e
28 the shear strength of a metal is commonly determined in which one of the following tests a. Bending test b. Compression test c. Flexure test d. Tensile test e. Torsion test
Ans: e
8 the flow curve describes the property of metals known as which one of the following a. Ductility b. Engineering strain c. Fracture stress d. Strain hardening e. Tensile strength
Ans: e
Modulus of elasticity
a factor which relates how much a material will stretch to it's stress
Amorphous
a material that has no significant short and long range order of it's atoms
Ductility
a measure of the degree of plastic deformation that has been sustained at fracture
Close-packed plane
a plane where almost all neighbor in atoms will be touching
Strain hardening
a process to increase dislocation density to impede dislocation motion
Recrystallization
a solid state capability, based on temperature, to grow new grains.
Engineering stress
axial load divided by the original cross sectional area of the sample
Eutectic reaction
liquid solid + solid
Fatigue limit
stress level below which fatigue failure will not occur
Fatigue failure
the ability of a material to fail under repeated loading, even when the load is lower than yeildjng or ultimate strength
