ceeCE60-Fall_07-mt2-Monteiro-exam

ceeCE60-Fall_07-mt2-Monteiro-exam - 0 ,7 $ 0' ”...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
Background image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 0 ,7 $ 0' ” UNIVERSITY OF CALIFORNIA AT BERKELEY DEPARTMENT OF CEE J ‘ SPRING SEMESTER, 2007 Instructor: PJ. M. Monteiro i , Name: _: i CE 60 — EXAMINATION Please 'usti all our answers 496 g A NE.“ N_fi+\‘ Question 1 (30 points) h g ; LIVKS; I I 1) Atomic packing factor (APF) is defined as:% 560% ~ 2 volume of atoms in unit cell / b a H a I: b ” 3 7X APF =-—~——~“ ’ 2&1 g 3," volume of unit cell 2 Compute the atomic packing fac r for the BCC unit cell. (10 points) b“: a 1 : C4") 1 H 3 8X6?) ‘ll: am it s I? Kazl’ctz; (4“) arr-71 _?f C m zégwr‘ {so}: (“H257 a2,- (we. C 's . “"2) In the absence of stress, the center togcgnter dist rice 0 t 3 6 atoms 15 0.248 nm - CL : H r Under the tensile stress of 100 MPa along this direction, the atomic distance increases RTE/E 0.2489 nm, Calculate ggvmpdulus of elasticity (5 points) 2 .. :IGDHFQ JfV‘AJ/uv: 0 [+8.21 p, 5 :0»69362‘40313E """ m. . . a—xI-w. . . 9' 3624 ‘w 3) Does the elastlc modulus measure the resrstance of a materi to elastic or plastic} ” EW__ __<,,_ deformation? (5 points) ‘/_ if“. V 2. 75 x to" 4) A sample is tested and for a given load the true strain is equal to ln(1/5). Compute max— englneering stram at this load. (5 pomts) 6T :— lm (is H) [Mo/i) : LA (654%) R 5) Stch can undergo two types of structural changes associated with phase changes. One is v diffusive and the other is displacive. The formation of pearlite is an example of} U M transformation (5 points) / > O / 6E +1 : C 1 “PM >7 W GZL‘: 3:: 7’23; my) ’7 W {—95 “J / \ W- Question 2 (30 points) I) Consider the stress-strain curve shown in Fig. l for a high—strength aluminum alloy. a) Concentrate on Figure la which shows the initial portion of the stress-strain curve. Use that diagram to determine the elastic modulus of the aluminum alloy. Be sure to Show on Fig. la how you made the determination. (5 points) b) Determine the 0.2% offset Yield Point for the tested alloy/ Be sure to show on Fig. l a how you made the determination (5 points) I c) Determine the ultimate tensile strength for the tested alloy. Be sure to show on Fig lb how you made the determination. (5 points) d) Draw on Fig. 1b an approximate representation of the true stress-engineering strain for the high strength alloy tested (5 points) e) Assume that the sample was loaded to 85,000 psi and then unloaded. Compute the elastic recovery and the plastic deformation. Be sure to show on Fig lb how you made the determination (10 points) v M 35”?”5 SW“ _ _ 90000 fl) 0') cV’W’ D. " D. m“ 60000 . m” 3 5 60000 175 “:75 c» 40000 C) .E E 8 $ 30000 .E 20000 .E C” U) .E x I UCJ o .4, ,L M o J, , , .. 0.002 0.004 0.006 0.008 0.01 O 0.02 _0.04 .006 0.08 0.1 Engineering strain Engineering strain Flgla Fig. 1b :26. W, WM’ \ a- U7 _ 7"“‘995‘ : ixlo7P$I /’ b— g '2 .9 78 »~w——--~ Question 3: (40 points) 1) Suppose that you have a steel alloy with an unknown amount of carbon. Assume that a sample has been heated to 950 C for two hours and now has been slowly cooled to 720 C. On microscopic examination it is found that the steel has 20% perlite and the remainder is proeutectoid ferrite. What is the Wei ght percent carbon in steel? (13 points) 11) A 0.95 percent C plain-carbon steel is slowly cooled from about 1000°C to a temperature just slightly below 723°C. (at) Calculate the weight percent eutectic carbide present in the steel. (15 points) (b) Calculate the weight percent perlite present in the steel. (12 points) IBM! 900 800 a 4m, om ; 723m Temperature r “C”; ‘1 E a S (M be? 0.8 ' .45’ Weigle pemcntcmhon 3 “X b 2 , : ,3’A 8 .5109. 1 Q'ézq /"‘ “ p ; WK ’ _______ w—A‘/’ ; "1:22:70 4/) W “Va 3:0” E VO—fl— “My”! W “AX/‘33:!) M 0,13qgitfié 5767‘ '99. - r675.‘ ~5L - ’5' l ’_ w 0'92 5—5 W W 6’é7_rg Tyw ’ pin; : Euécctlc . pngéfi-fl'OIUY 0. NH : i ’ 2;) ...
View Full Document

This note was uploaded on 07/11/2009 for the course CEE cee taught by Professor Monteiro during the Fall '05 term at University of California, Berkeley.

Page1 / 3

ceeCE60-Fall_07-mt2-Monteiro-exam - 0 ,7 $ 0' ”...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online