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






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






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






4. - 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






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






6. 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






7. 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






8. Occur when lots of dislocations move.






9. 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.






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






11. 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






12. 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.






13. 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."






14. Light Amplification by Stimulated Emission of Radiation






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






16. 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.






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






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






19. Sigma=ln(li/lo)






20. These materials are relatively unaffected by magnetic fields.






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






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






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






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






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






26. Is analogous to toughness.






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






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






29. - 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






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






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






32. Different orientation of cleavage planes in grains.






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






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






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






36. 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






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






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






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






40. 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.






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






42. 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






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






44. 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.






45. 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.






46. Superconductors expel magnetic fields - This is why a superconductor will float above a magnet.






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






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






49. Second phase particles with n > glass.






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