Material Science

1) A body which does not contain voids or empty spaces is known as

a. An isotropic bodyb. continuous bodyc. heterogeneous bodyd. crystalline body

2)If a body has identical properties all over it is known as

a.isentropicb. ductilec.homogenousd.elastic

3) Some engineering materials are made up of more than one phase, with different mechanical properties such materials are known as

a. Discontinuousb. Brittlec. Elasticd. Heterogeneous

4) Which of the following is the hardest material?

A. high speed steelb. Diamondc. stainless steeld. cemented carbide

5. The miller indices of the diagonal plane of cube area.110b.111c. 100d. 000 6. Burgers vector isa. estimation of force in subsitutional atomsb. a defect in crystal structurec. defect in crystal latticesd. property of dislocation

7. Close packed hexagonal space lattice is found ina. chromium , tungstenb. cobalt, antimony and bismuthc. aluminum , copperd. calcium , magnesium

8. The atomic packaging factor for Face centered cube is nearly a) 0.74 b) 0.52 c) 0.68 d) 0.81

9. Which of the following element has H.C.P structure?a. aluminumb. molybdenumc. cadmiumd. chromium

10. The material which has the same elastic properties in all direction is called

e. brittle materialf. ductile materialg. homogenous materialh. isotropic material

11. Recrystallisation temperature is .......................times the melting point for pure metals and............................ times the melting temperature for alloys

a) .3,.5b) .2,.1c) .6,.9d) 1,2

12. ..................................... is indicative of the rate at which atoms diffuse

e) temperaturef) speciesg) massh) diffusion coefficient D

13. ----------------- are responsible for the functioning of most semi conductor devices

a) line defectsb) impuritiesc) grain boundriesd) tilt boundries

14. ------------------- defects in a crystal lattices causes an increase in its internal energy

e) Point defectsf) Line defectsg) Structure defects h) Volume defects

15. Whenever the arrangement of atoms is not in proper sequence throughout the crystal the defect caused is known as

a) grain boundryb) tilt boundryc) stacking faultd) edge dislocation

16. whenever grains of different orientation separates the general pattern of atoms and exhibits as boundry, the defect caused is called

e) tilt boundryf) grain boundryg) twin boundryh) stacking fault

17. whenever a half plane of atoms is inserted between the planes of atoms in perfect crystals the defect produced is known as

a) edge dislocationb) screw dislocationc) interstitial defectd) electronic defect

18. --------------------- defect is the combination of vacancy and interstials

e) schottky defectf) grain boundaryg) twin boundaryh) frankel defects

19. During recovery of a cold worked poly crystalline material dislocations

a) migrateb) multiplec) rearranged) mostly disappear

20. Recrystallisation temperature is onee) at which new spherical crystals first begin to form ones

when a strained metal is heatedf) at which crystal begins to appearg) at which crystal start growing in sizeh) at which polycrystalline changes occur

21. a ductile fracture is characterized bya) rapid rate of crack propagationb) negligible deformationc) fragmentation into more than two piecesd) appreciable plastic deformation prior to propagation of

crack

22. the fatigue strength of materials increases

e) with temperaturef) by under stressing the specimeng) by having scratch on the surfaceh) by having notch on the surface

23. The property of material by which slow extension of materials takes place with the time at constant load is known as

a) creepb) plasticityc) elasticityd) Malleability

24. Fatique cracks in metals normally starts ate) centre of the specimenf) any spot in the specimeng) core of the specimenh) ends of the specimen

25. Which of the following material can withstand maximum shock without failure?

a) white cast ironb) chilled cast ironc) malleable cast irond) grey cast iron

26. The order in which events lead to fatigue failure is

e) crack growth , fracture , nucleationf) fracture, crack growth, nucleationg) crack growth, nucleation, fractureh) nucleation, crack growth, fracture

27. Which of the following material can bear sudden and excessive shocks better?

a) wrought ironb) cast ironc) pig irond) white iron

28. dislocation cross- slip is difficult in those material which have

e) high stacking fault energyf) large number of slip systemsg) low stacking fault energyh) high work - hardening rate

29. In compression, a prism of brittle material will break

a) by crushing into piecesb) by forming a buldgec) in direction perpendicular to application of loadd) by shearing along oblique plane

30. Below ECT small grain sized materials stronger due to .......................... to improve strength

e) grain sizef) high density of grain boundariesg) space between grainsh) grain boundary

31. when a piece of 0.2% carbon steel is heated above third critical point the steel is a solid solution of carbon in gamma iron and it is called

a) Austeniteb) Peralitec) Cementited) Eutectoid

32. A steel with 0.8% carbon and 100% peralite is called

e) Austenitef) Solidusg) Eutectoidh) Peralite

33. eutectoid steels have carbon contenta) 0.83%b) 0.2%c) 0.7%d) 1.7%

34. Cast iron containing 6.6% carbon is

e) Black in colour containing peralitef) Black in colour containing ferriteg) Grey in colour containing peralite and ferriteh) Whitish containing cementite only

35. iron - carbon alloys containing 1.7 to 4.3% carbon is called as

a) eutectic cast ironb) hyper - eutectic cast ironc) hypo - eutectic cast irond) white cast iron

36. Pure iron has the structure of

e) Peralitef) Austeniteg) Cementiteh) Ferrite

37. if the steel at room temperature is magnetic, the presence of which constituent can be ruled out

a) Ferrite b) Peralitec) Austenited) Cementite

38. what is the minimum carbon % required in steel, so that it may respond to hardening by heat treatment

e) 0.2%f) 1%g) 1.2%h) 2%

39. austenite is the combination ofa) ferrite and cementiteb) perlite and ferritec) ferrite and iron graphited) cementite and perlite

40. Hypo eutectoid steels have carbon content

e) greater than 0.83%f) equal to 0.83%g) more than 2%h) less than 0.83%

41. Heat treatment in which a material that is exposed to an elevated temperature for an extended time period and then slowly cooled is called as __________

a) Nitridingb) Annealingc) Carburisingd) Carbonitriding

42. _________ refers to accelerated cooling.

e) Quenchingf) Annealingg) Temperingh) Hardening

43. ________________ is the process of heating a martensite steel at a temperature below the eutectoid transformation temperature for a specified time period and is cooled slowly to room temperature.

a) Flame hardeningb) Induction hardeningc) Carbonitridingd) Tempering

44. What is the temperature range for high temperature tempering?

e) 500ºC to 650ºCf) 250ºC to 350ºCg) 350ºC to 450ºCh) 650ºC to 750ºC

45. Heat treatment of a steel involving a slow cool through the martensite transformation range to reduce stresses associated with that crystallographic change is called as __________

a) Austemperingb) Annealingc) Martemperingd) Nitriding

46. ___________ is a process of introducing both nitrogen and carbon to obtain hard surface of the steel components.

e) Carburising f) Carbonitriding g) Nitriding h) Hardening

47. In ________ a hardened steel ball indenter is forced into the surface of the metal to be tested.

a) Izod testb) Charpy testc) Rockwell hardness testd) Brinell hardness test

48. _________ is an type of impact test.

e) Brinell hardness testf) Vickers hardness testg) Izod testh) Rockwell hardness test

49. Both hardness and tensile strength are indicators of a metal’s resistance to........................

a) elastic deformationb) plastic deformationc) viscoelastic deformationd) load

50. What is the diameter of the hardened stell indenter used in brinell hardness test?

e) 10mmf) 20mmg) 35mmh) 50mm

Answers

1) b 2) c3) d4) b5) a6) d7) b8) a9) c10)d

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11) a12) d13) b14) a15) c16) b17) a18) d19) c20) a

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21) d22) b23) a24) b25) c26) d27) a28) c29) d30) b

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31) a32) c33) a34) d35) b36) d37) c38) a39) c40) d

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41) b42) a43) d44) a45) c46) b47) d48) c49) b50) a

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