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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. Is analogous to toughness.






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






3. 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.






4. These materials are relatively unaffected by magnetic fields.






5. 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






6. Diffuse image






7. Cracks propagate along grain boundaries.






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






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






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






11. 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






12. The size of the material changes with a change in temperature - polymers have the largest values






13. 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






14. Measures Hardness 1. psia = 500 x HB 2. MPa = 3.45 x HB






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






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






17. 1. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.






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






19. Specific heat = energy input/(mass*temperature change)






20. 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






21. 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






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






23. Materials change size when temperature is changed






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






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






26. For a metal - there is no ______ - only reflection






27. Failure under cyclic stress 1. It can cause part failure - even though (sigma)max < (sigma)c 2. Causes ~90% of mechanical engineering failures.






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






29. The ability of a material to absorb heat - Quantitatively: The energy required to produce a unit rise in temperature for one mole of a material.






30. Sigma=ln(li/lo)






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






32. 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.






33. 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)






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






35. Undergo little or no plastic deformation.






36. Growth of an oxide layer by the reaction of oxygen with the substrate - Provides dopant masking and device isolation - IC technology uses 1. Thermal grown oxidation (dry) 2. Wet Oxidation 3. Selective Oxidation






37. Liquid polymer at room T - sandwiched between two sheets of glass - coated with transparent - electrically conductive film. - Character forming letters/ numbers etched on the face - Voltage applied disrupts the orientation of the rod- shaped molecule






38. - 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






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






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






41. Occur when lots of dislocations move.






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






43. 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.






44. 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.






45. Because of ionic & covalent-type bonding.






46. 1. Tensile (opening) 2. Sliding 3. Tearing






47. Width of smallest feature obtainable on Si surface






48. 1. Ability of the material to absorb energy prior to fracture 2. Short term dynamic stressing - Car collisions - Bullets - Athletic equipment 3. This is different than toughness; energy necessary to push a crack (flaw) through a material 4. Useful in






49. 1. General yielding occurs if flaw size a < a(critical) 2. Catastrophic fast fracture occurs if flaw size a > a(critical)






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