Test your basic knowledge |

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. Diffuse image






2. Cracks propagate along grain boundaries.






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






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






5. High toughness; material resists crack propagation.






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






7. Impurities added to the semiconductor that contribute to excess electrons or holes. Doping = intentional impurities.






8. Is analogous to toughness.






9. 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






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






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






12. Small Coercivities - Used for electric motors - Example: commercial iron 99.95 Fe






13. 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






14. These materials are "attracted" to magnetic fields.






15. Large coercivities - Used for permanent magnets - Add particles/voids to inhibit domain wall motion - Example: tungsten steel






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






17. Typical loading conditions are _____ enough to break all inter-atomic bonds






18. 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






19. 1. Necking 2. Cavity formation 3. Cavity coalescence to form cracks 4. Crack propagation (growth) 5. Fracture






20. 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






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






22. (sigma)=K(sigma)^n . K = strength coefficient - n = work hardening rate or strain hardening exponent. Large n value increases strength and hardness.






23. Materials change size when temperature is changed






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






25. Reflectiviy is between 0.90 and 0.95 - Metal surfaces appear shiny - Most of absorbed light is reflected at the same wavelength (NO REFRACTION) - Small fraction of light may be absorbed - Color of reflected light depends on wavelength distribution of






26. 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.






27. Different orientation of cleavage planes in grains.






28. This strength parameter is similar in magnitude to a tensile strength. Fracture occurs along the outermost sample edge - which is under a tensile load.






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






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






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






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






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






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






36. 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.






37. - A magnetic field is induced in the material B= Magnetic Induction (tesla) inside the material mu= permeability of a solid






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






39. 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.






40. 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






41. 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






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






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






44. Occur when lots of dislocations move.






45. Ohms Law: voltage drop = current * resistance






46. Becomes harder (more strain) to stretch (elongate)






47. -> fluorescent light - electron transitions occur randomly - light waves are out of phase with each other.






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






49. Plastic means permanent! When a small load is applied - bonds stretch & planes shear. Then when the load is no longer applied - the planes are still sheared.






50. 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."