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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. High toughness; material resists crack propagation.






2. 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






3. - 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






4. Cracks propagate along grain boundaries.






5. These materials are relatively unaffected by magnetic fields.






6. - 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






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






8. Is analogous to toughness.






9. 1. Metals: Thermal energy puts many electrons into a higher energy state. 2. Energy States: Nearby energy states are accessible by thermal fluctuations.






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






11. 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."






12. 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






13. 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.






14. Because of ionic & covalent-type bonding.






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

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16. 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






17. 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






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






19. 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






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






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






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






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






24. Undergo little or no plastic deformation.






25. Materials change size when temperature is changed






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






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






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






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






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






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






32. 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






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






34. Occur when lots of dislocations move.






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






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






37. Different orientation of cleavage planes in grains.






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






39. 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.






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






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






42. 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






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






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






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






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






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






48. 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






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






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