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Test1_and_solutions

# Test1_and_solutions - Materials 1M03 Test#1 2005 Part A The...

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Unformatted text preview: Materials 1M03, Test #1 2005 Part A: The following multiple choice questions are worth 3 marks each. In each case, put your answers on the scan sheet (marked McMaster University Examination Answer Sheet). Read the Marking Directions on this sheet carefully before starting. 1. You want to design a panel like the one shown below. Your objective is to minimize the mass of the panel, while maintaining a certain stiffness S given by the formula S = CEWI3 £02123) , where E is the modulus, C is a given constant, W is the width of the panel, L is its length and t is its thickness. Assuming the thickness and length are ﬁxed by design and cannot be changed, ﬁnd a materials index that can be used to identify the best material to use for the panel. Assume the material in question has a density denoted by ,0 and a yield stress denoted by 0' y a b. Q d. e none of the above 2. The atomic weight of copper Cu is 63.55 and Nickel is 58.69, while the density of Cu is 8.94gr’cm 3and that of Ni is 8.9 g/cm“. Copper and Nickel both have an FCC crystal structure. Compute the number of Ni atoms in one gram of an alloy that consists of 90 weight percent copper and 10 weight percent nickel. , 9172 - M’CD/ MM 19 a. . Cl Mﬂssgbkll} (Til X /?V " ' 906 y! b. 8.3e21 {gamut \$0 3 ' eQ c. 7.462] Nazi. It Sim kl} plow" 1'. AH“ :- ql}q°l‘ﬂ0 D/afbvn d. 6.262] Ne none of the above 0 ,r 5U ,{ “’ ﬁf‘gM'JWZ/‘Q .4620”) ‘-""""‘7 o (J f .5 Page 2 of2 Materials 1M03, Test #1 2005 ,5 3. Which of the following statements is most correct .The elastic modulus of a metal is dictated entirely by bonding SEQ 00A 3 P’Wﬂfs b) The elastic modulus of a metal is dictated by a combination of bonding and microstructure c) The elastic modulus of a metal is controlled entirely by microstructure d) The elastic modulus is a function of neither microstructure nor bonding 4. Select the correct miller indices for the plane shown below _3 b)[1151 3 C) [115] d) [223] e) [2 —2 3] 5. The concentration of vacancies in copper at room temperature (25° C) is 1.815 x108 vacancies! 0713. What temperature will be needed to heat the copper such that the concentration of vacancies produced will be 1000 times more than the equilibrium concentration of vacancies at room temperature? Assume that the activation energy of copper vacancies is 20,000 cala’mol. Round to the nearest F (ail/Nola degree. |°<€lSYKQ+ angwu4—‘S -ﬂo ‘e /k7'r 7‘0““ 0/; ,Zoﬂpoo yea! my 3/69} "‘3 CM 12 : meets-0” s/mha ——-" - r) ) ﬂo J QJSﬁYIFU ijjrﬂ-p 1:696”; z?gk ,( —or w? ,- Q000l<| mix-o K):- ‘E. Jaws e 421' anti ”3 ofé‘t. 79s ageao 3 {Wear/0" I“ , a. QB 5/01 ____ «AQ/ { /___————- 2g “—2373 9 /£TK: EM 9 5? W022 :3) TX :CCP/‘Z /2(, 9%,: Materials 1M03, Test #1 2005 9 102°C b. 110°C c 540°C d. 98°C e. none of the above 6. The inter-planar spacing for the (1 1 1) of aluminum is found to be 0.234 nm, select the correct lattice parameter. :0- ‘x a! Q'Iiﬁifl-OIDEIHM\ a. 0.413nm 0L m . c. 0.202 nm d. 0.541 nm 7. The atomic weight of copper Cu is 63.55 and Nickel is 58.69, while the density of Cu is 8.94 g/cm3and that of Ni is 8.9 gfcml. Copper and Nickel both have an FCC crystal structure. Calculate the weight percent of nickel in an alloy that consists of 90 atom percent cop er and 10 atom percent nickel. 6010-7 W ’Fc/rmrj; 4.3.9 M (a .//S7[W b)10.3 . . c) 97 We M : ( xo «1% 33/; ;_§<r_._§r_j/m/L.. WEE/"U d 9-3 (”mm m gems/w... ivraysrzcw muses/W. l 6) none of the above .— cf 3‘ 8. A tilt boundary may often be viewed as the result of a series of a. vacancy point defects b. interstitial point defects nl . c. screw dislocations ' b“ > Paoa'q j? 7 (a-.. 'bedge dislocations e. impurity atoms (la/2" Page 4 of4 Materials 1M03, Test #1 2005 9. Which of the following is not true a) Metals are more likely to be crystalline than amorphous b) P lymers can be completely crystalline (,[A :5 Mei—4 9' c) Metallic bonding is non-directional d) Polymers are often amorphous 10. The best list to describe the attributes of a solventfsolute pair that determine the likelihood of a substitutional solution is: a. atomic radii, melting points, atomic weights ®rystal structures, valences, atomic radii 35.9, 630 axe ( Ci 0. valences densities atomic numbers ..5 . 3 _ _ [mﬁcxiilgs‘vf d. dens1t1es, atomic numbers, melting pOmts e. valences, atomic numbers, atomic weights 11. Consider the unit cell for MgO shown below, which is comprised of Mg2+ atoms represented by the dark spheres (not marked with an x) and the 02' ions represented by the lighter spheres (marked with an x). The co-ordination number of each atom is six. In the ﬁgure, the Mg2+ ions are at the centre of each edge, while the 02' ions are at the corners and mid faces. In the centre of the unit cell sits an Mg2+ ion. The atomic mass of i’t/{g2+ is 24.312 g/mol and that of 02’ is 16g/mol. The radius of Mg“ is 0.066nm and the radius of 02' is 0.132 nm. Calculate the density of MgO. Q J Aug"; ﬂip/,g/‘Zi/mo/ A67” 5 Mj/wor'” M. Page 5 of5 maimaz- =5 2<orosem+2asu22 _.> .- o. 3% n... Materials lMU3, Test #1 2005 a. 3.-’-19gs’nr:m3 64.31 gr’cm3 c. 5.31g/cm3 d. 9.31g2‘cm3 e. 4.39gfc’m3 Page 6 of6 Materials 1M03, Test #1 2005 2. [8 marks] 3) Sketch a diagram showing how the energy changes with separation distance as two atoms are brought together from inﬁnite separation. SQ .Q Cb; Include plots for the energy of attraction, the energy of repulsion and the total energy. Indicate the bond length on the diagram b) Which feature on the graph controls the elastic modulus? c) The force of attraction of two atoms in equilibrium in an ionic crystal is -1.5 x lO'mN. what is the force of repulsion? ( L3) 3 EON/1&5 ‘ 'H/ﬁ CUT Vagurk Omkwiao—HM Jag-tr, Womb/shut) I 44A ,Lcaw CMV'AM ’5 “84”” 6 vvaJVV‘ ‘95 UM 6 f_____,__,.—/' Page 8 of8 Materials 1M03, Test #1 2005 3. [6 marks] A substitutional solid solution contains 83.4 atomic percent copper and 16.6 atomic percent nickel. Cu has a density of 8.94 g/ch, while the density of Nickel is 8.90 g/ cm3. The atomic weight of Nickel is 58.69 g/mole and the atomic weight of copper is 63.55 g/mole. Assume that the alloy forms an FCC crystal structure. .1 , a) Find the expected (average) number of nearest neighbors to a copper atom .l. _ ., M fir-II ’ wt. 1-: Kat/"\- WE i ‘ _ that are nickel. . ..\; it». ,{4 WP ' ‘ . I i M» A34 " b) Flnd the (3meth number of mckel atoms on a 1 micron by 1 mlcron by 1 3- i - micron cube of the alloy. (0 - (1’ 3- 9 Mai éasmﬂ 344.442, use.“ AM (41°30le) m , f? (’3 h} (95';_c| Jj’anjkég'q-gjzw°u\)+ (IIIL'ILM ‘\ -’/______,__.——————‘—"_ €6.94 5/91»? 3‘iij/5’V“; 3&95 -t' ’WBMB : 3,0134er _ ?>to|.—-§L'on‘j/W3 XKIO wxwvo m iii/km”; "‘ mo : 19, 5 “ﬂy: a -:, ' matte/w) WWHFQLQMMX “‘HMWMBSWW) ,. K .1c.ed°/sua_,)(<s.ss ﬁlm-1 )‘l’( J2 ----------------------- THE END ‘ aim ~ .- (0.:s€3*<(°6-°’3““’° 5) MW Duh MW / ~62 V a m“ N“ _, 6:. "(MW/0'23? 3 gg' a W MM Page9of9 (.02 won/ea ' - 24.412 WmM dam ...
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