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






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






3. 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.






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






5. Second phase particles with n > glass.






6. Emitted light is in phase






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






8. 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






9. 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






10. Heat capacity.....- increases with temperature -for solids it reaches a limiting value of 3R






11. - 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






12. 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.






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






14. 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.






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






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






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






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






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






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






21. 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.






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






23. A three terminal device that acts like a simple "on-off" switch. (the basis of Integrated Circuits (IC) technology - used in computers - cell phones - automotive control - etc) - If voltage (potential) applied to the "gate" - current flows between th






24. 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.






25. 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






26. These materials are relatively unaffected by magnetic fields.






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






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






29. - 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






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






31. 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.






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






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






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






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






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






37. 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.






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






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






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






41. Undergo little or no plastic deformation.






42. Sigma=ln(li/lo)






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






44. Cracks propagate along grain boundaries.






45. Is analogous to toughness.






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






47. 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.






48. Width of smallest feature obtainable on Si surface






49. 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






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