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. Occurs at a single pore or other solid by refraction n = 1 for pore (air) n > 1 for the solid - n ~ 1.5 for glass - Scattering effect is maximized by pore/particle size within 400-700 nm range - Reason for Opacity in ceramics - glasses and polymers.






2. Occur when lots of dislocations move.






3. These materials are relatively unaffected by magnetic fields.






4. Second phase particles with n > glass.






5. 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.






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






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






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






9. - Metals that exhibit high ductility - exhibit high toughness. Ceramics are very strong - but have low ductility and low toughness - Polymers are very ductile but are not generally very strong in shear (compared to metals and ceramics). They have low






10. 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






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






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






13. 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)






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






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






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






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






18. Hardness is the resistance of a material to deformation by indentation - Useful in quality control - Hardness can provide a qualitative assessment of strength - Hardness cannot be used to quantitatively infer strength or ductility.






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. Tc= critical temperature- if T>Tc not superconducting 2. Jc= critical current density - if J>Jc not superconducting 3. Hc= critical magnetic field - if H > Hc not superconducting






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






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






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






24. 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






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






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






27. 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






28. Materials change size when temperature is changed






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






30. Digitalized data in the form of electrical signals are transferred to and recorded digitally on a magnetic medium (tape or disk) - This transference is accomplished by a recording system that consists of a read/write head - "write" or record data by






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






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






33. (sigma)=F/Ai (rho)=(rho)'(1+(epsilon))






34. 1. Hard disk drives (granular/perpendicular media) 2. Recording tape (particulate media)






35. Because of ionic & covalent-type bonding.






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






37. 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."






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. High toughness; material resists crack propagation.






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






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






42. 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






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






44. Loss of image transmission - You get no image - There is no light transmission - and therefore reflects - scatters - or absorbs ALL of it. Both mirrors and carbon black are opaque.






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






46. A measure of the ease with which a B field can be induced inside a material.






47. Undergo little or no plastic deformation.






48. If a material has ________ - then the field generated by those moments must be added to the induced field.






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






50. Transmitted light distorts electron clouds - The velocity of light in a material is lower than in a vacuum - Adding large ions to glass decreases the speed of light in the glass - Light can be "bent" (or refracted) as it passes through a transparent