quiz-1-winter_2007

quiz-1-winter_2007 - Materials Science and Engineering...

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Unformatted text preview: Materials Science and Engineering Department Introduction to Materials Science 104 Prof. Eric Bescher Winter 2007 LAST NAME: FIRST NAME: GRADE QUIZ #1 Monday January 28, 2007 12pm-1pm 1 page of notes. Question 1- Multiple Choice (18 points) l-Which'list oLbonding types makes the most sense to you? 1— Covalent, Ionic, Van der Waals (\Z—Wan der Waals, Hydrogen 3— Covalent, Metallic, Hydrogen 2—For a low-carbon steel, as the % cold work increases: 1- The yield strength decreases ® The ductility decreases 3— The yield strength remains unchanged 3- A typical value for the modulus of elasticity a metal is: £30 to 300 GPa El 30 to 300 MPa D 30 to 300 Pa U30 to 300 mZ/s 4—1- The coordination number for the FCC crystal structure is 5- A Schottky defect is composed of... Cation/anion vacancy pairs. b- Vacancy/interstitial pair. 0— Mixed dislocations. d— Screw dislocations only. 6— BCC is a close-packed structure U True 8' False Question 2- 140 points) (1)Calculate the atomic packing factor of the foe and bcc structures. Show your calculations.(20) See byvk baa “®.6? Fm ‘. 0.17% (2)Express the volumes of a ECG and a FCC unit cell in terms of the atomic radius R. (10) » a 3 - a 3 E , ’— 5) Vg-QB: i R? : V1932 K bac. Li‘R- ‘30s 3 Fact (M: fiat 7) ”:q? g3 = 22152 (4 i 2V2 (3)Are these results consistent with (1)? Why or why not? (10) Wm” (L (1‘46: Vileuvw. 6-? “H9 {EL Kw Z WW4 of ‘f’fle 5W M (Mina; fie,“ {W is}; M can/Q) ’L 823/ 19cc. [Zea 0M9 Question 3- 110 points! Consider the gas carburizing of a gear of 1020 steel at 927°C. Calculate the time in minutes necessary to increase the carbon content to 0.40% at 0.50 mm below the surface. Assume that the carbon content at the surface is 0.90 % and that the steel has a nominal carbon content of 0.20% D 927oc=1.28 x 10'11 m2.s'l 036:9- ofws—Oio dyed: (-0.5xmtg 0.6103— 0.7. Z iii-78x15”; E 3 -—o,‘il\‘e.%;~€x¥ (OS—“‘3' (261.?2’tho'fl (f w— J) 7) 0'57MD a; 9.43; E: Qécb‘D p 5,- We mm écgss Question 4- (10 points) In the curves below: Which material has the highest modulus? Which material has the highest ductility? Which material has the highest toughness? Which material does not exhibit plastic deformation before failure? Explain your answers. Material I Material 11 stress (0) ‘ Strain (e) Question 5 -( 10 points) (1)Write the electronic configuration of Li and F, as well as that of the related singly— » I ‘ 7 ionized ions. r @ (J ‘. is? 275‘ u +3 “SE V: I52 25? Zpg FT {5? 259?; \\ (2) What type of bonding would you expect in UP? Justify your answer. 1": (2:9 ' <:-_\ Kr ,n‘\ __ 1 fly a A ‘1 «A \ r 4/ V V“ K; Question 6- 112 points) Draw or label the following planes ...
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quiz-1-winter_2007 - Materials Science and Engineering...

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