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