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






2. Stress concentration at a crack tips






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






4. Energy is stored as atomic vibrations - As temperature increases - the average energy of atomic vibrations increases.






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






6. 1. Imperfections increase resistivity - grain boundaries - dislocations - impurity atoms - vacancies 2. Resistivity - increases with temperature - wt% impurity - and %CW






7. The ability of a material to transport heat - Atomic Perspective: Atomic vibrations and free electrons in hotter regions transport energy to cooler regions - Metals have the largest values






8. 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.






9. A high index of refraction (n value) allows for multiple internal reactions.






10. # of thermally generated electrons = # of holes (broken bonds)






11. Allows flow of electrons in one direction only (useful to convert alternating current to direct current) - Result: no net current flow






12. Diffuse image






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






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






15. Undergo little or no plastic deformation.






16. 1. Diamagnetic (Xm ~ 10^-5) - small and negative magnetic susceptibilities 2. Paramagnetic (Xm ~ 10^-4) - small and positive magnetic susceptibilities 3. Ferromagnetic - large magnetic susceptibilities 4. Ferrimagnetic (Xm as large as 10^6) - large m






17. The ability of a material to be rapidly cooled and not fracture






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






19. 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.






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






21. 1. Impose a compressive surface stress (to suppress surface cracks from growing) - Method 1: shot peening - Method 2: carburizing 2.Remove stress concentrators.






22. Light Amplification by Stimulated Emission of Radiation






23. 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.






24. Occur when lots of dislocations move.






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






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






27. 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






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






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






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






31. Sigma=ln(li/lo)






32. Flaws and Defects - They concentrate stress locally to levels high enough to rupture bonds.






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






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






35. Process by which metal atoms diffuse because of a potential.






36. Emitted light is in phase






37. - The emission of light from a substance due to the absorption of energy. (Could be radiation - mechanical - or chemical energy. Could also be energetic particles.) - Traps and activator levels are produced by impurity additions to the material - Whe






38. 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






39. 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






40. Measures impact energy 1. Strike a notched sample with an anvil 2. Measure how far the anvil travels following impact 3. Distance traveled is related to energy required to break the sample 4. Very high rate of loading. Makes materials more "brittle."






41. They are used to assess properties of ceramics & glasses.






42. Width of smallest feature obtainable on Si surface






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






44. Without passing a current a continually varying magnetic field will cause a current to flow






45. 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.






46. These materials are relatively unaffected by magnetic fields.






47. 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






48. Dramatic change in impact energy is associated with a change in fracture mode from brittle to ductile.






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






50. Increase temperature - no increase in interatomic separation - no thermal expansion