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Engineering Materials

Subject : engineering
Instructions:
  • Answer 50 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. Measures Hardness 1. psia = 500 x HB 2. MPa = 3.45 x HB






2. Width of smallest feature obtainable on Si surface






3. Wet: isotropic - under cut Dry: ansiotropic - directional






4. The Magnetization of the material - and is essentially the dipole moment per unit volume. It is proportional to the applied field. Xm is the magnetic susceptibility.






5. 1. Fluorescent Lamp - tungstate or silicate coating on inside of tube emits white light due to UV light generated inside the tube. 2. TV screen - emits light as electron beam is scanned back and forth.






6. Cracks propagate along grain boundaries.






7. 1. Yield = ratio of functional chips to total # of chips - Most yield loss during wafer processing - b/c of complex 2. Reliability - No device has infinite lifetime. Statistical methods to predict expected lifetime - Failure mechanisms: Diffusion reg






8. Light Amplification by Stimulated Emission of Radiation






9. A parallel-plate capacitor involves an insulator - or dielectric - between two metal electrodes. The charge density buildup at the capacitor surface is related to the dielectric constant of the material.






10. Heat capacity.....- increases with temperature -for solids it reaches a limiting value of 3R






11. Not ALL the light is refracted - SOME is reflected. Materials with a high index of refraction also have high reflectance - High R is bad for lens applications - since this leads to undesirable light losses or interference.






12. To build a device - various thin metal or insulating films are grown on top of each other - Evaporation - MBE - Sputtering - CVD (ALD)






13. Growing interconnections to connect devices -Low electrical resistance - good adhesion to dielectric insulators.






14. 1. Electron motions 2. The spins on electrons - Net atomic magnetic moment: sum of moments from all electrons.






15. These materials are relatively unaffected by magnetic fields.






16. Created by current through a coil N= total number of turns L= length of turns (m) I= current (ampere) H= applied magnetic field (ampere-turns/m) Bo= magnetic flux density in a vacuum (tesla)






17. Cracks pass through grains - often along specific crystal planes.






18. No appreciable plastic deformation. The crack propagates very fast; nearly perpendicular to applied stress. Cracks often propagate along specific crystal planes or boundaries.






19. Metals are good conductors since their _______is only partially filled.






20. Specular: light reflecting off a mirror (average) - Diffuse: light reflecting off a white wall (local)






21. With Increasing temperature - the saturation magnetization diminishes gradually and then abruptly drops to zero at Curie Temperature - Tc.






22. These are liquid crystal polymers- not your normal "crystal" -Rigid - rod shaped molecules are aligned even in liquid form.

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23. Defines the ability of a material to resist fracture even when a flaw exists - Directly depends on size of flaw and material properties - K(ic) is a materials constant






24. Ability to transmit a clear image - The image is clear.






25. Degree of opacity depends on size and number of particles - Opacity of metals is the result of conduction electrons absorbing photons in the visible range.






26. Allows you to calculate what happened G=F' x cos(lambda) - F=F' x cos(phi)






27. Measures Hardness - No major sample damage - Each scales runs to 130 but only useful in range 20-100 - Minor load is 10 kg - Major load: 60 kg (diamond) - 100 kg (1/16 in. ball) - 150 kg (diamond)






28. Dimples on fracture surface correspond to microcavities that initiate crack formation.






29. 1. Stress-strain behavior is not usually determined via tensile tests 2. Material fails before it yields 3. Bend/flexure tests are often used instead.






30. 1. Ductility- % elongation - % reduction in area - may be of use in metal forming operations (e.g. - stretch forming). This is convenient for mechanical testing - but not very meaningful for most deformation processing. 2. Toughness- Area beneath str






31. Another optical property - Depends on the wavelength of the visible spectrum.






32. Rho=F/A - tau=G/A . Depending on what angle the force is applied - and what angle the crystal is at - it takes different amounts of force to induce plastic deformation.






33. Occur due to: restrained thermal expansion/contraction -temperature gradients that lead to differential dimensional changes sigma = Thermal Stress






34. Different orientation of cleavage planes in grains.






35. Transformer cores require soft magnetic materials - which are easily magnetized and de-magnetized - and have high electrical resistivity - Energy losses in transformers could be minimized if their cores were fabricated such that the easy magnetizatio






36. The magnetic hysteresis phenomenon: Stage 1: Initial (unmagnetized state) Stage 2: Apply H - align domains Stage 3: Remove H - alignment remains => Permanent magnet Stage 4: Coercivity - Hc negative H needed to demagnitize Stage 5: Apply -H - align d






37. Materials change size when temperature is changed






38. There is always some statistical distribution of flaws or defects.






39. Emitted light is in phase






40. Process by which geometric patterns are transferred from a mask (reticle) to a surface of a chip to form the device.






41. Resistance to plastic deformation of cracking in compression - and better wear properties.






42. Elastic means reversible! This is not a permanent deformation.






43. Found in 26 metals and hundreds of alloys & compounds - Tc= critical temperature = termperature below which material is superconductive.






44. As the applied field (H) increases the magnetic domains change shape and size by movement of domain boundaries.






45. Undergo extensive plastic deformation prior to failure.






46. Is reflected - absorbed - scattered - and/or transmitted: Io=It+Ia+Ir+Is






47. Sigma=ln(li/lo)






48. Cp: Heat capacity at constant pressure Cv: Heat capacity at constant volume.






49. ...occurs in bcc metals but not in fcc metals.






50. 1. Data for Pure Silicon - electrical conductivity increases with T - opposite to metals