mt_sol_B - OHIO Materials Science and Engineering 564 m...

Info icon This preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
Image of page 1

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

View Full Document Right Arrow Icon
Image of page 2
Image of page 3

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

View Full Document Right Arrow Icon
Image of page 4
Image of page 5

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

View Full Document Right Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: OHIO Materials Science and Engineering 564 m Egéjgflfw’ {55; £3: ‘Ufaiiéz" /////// Ligamst 5.5;: LlNlVElel'H Midterm Exam B February 13, 2008 Instructions: Kev You have approximately 50 minutes to complete this exam. Answer all 8 questions. Write your answers in the spaces provided. Show starting governing equations and calculations in your work in order to receive partial credit. Enter your course code here: You may use your single—sided sheet of personal notes and, a calculator. The point values for each question are given below. Good luck! 1 __/13 2 ____/10 3 “/12 4: _/.lO 5: ___/Tl() 6' ___/12 7 ___/'12 8 __/21 TOTAL: / 100 1/6 MSE 564 Midterm W/2008 Anderson-B Computing strain (13 points) In the figure below, the angle BOA is changed to B’OA’ due to deformation. Determine numerical values of as many components of strain as possible based on information in the figure. Leave blank any entries that cannot be determined. You may assume small strain theory. Note the axis labels in the figure. ~——> «(1,203) Y 10 20 EKCLM IA“ page 2 / 6pages total MSE 564 Midterm WI2008 Anderson—B 2. Computing Change in Volume (10 points) A cube with undeformed edge length equal to 1cm is deformed with a uniform strain state: 005 0.06 0.02 [su]= 0.06 0.01 0.04 0.02 0.04 —0.03 What is the change in volume due to the uniform strain state? me Raw-6,, Small Sin/mm «We»? 8 was 55 AV: 0.03% = 0.03%?» 3. Deformation in a Single Crystal of Copper (12 points) Table 1.3 of Hertzberg provides the elastic constants for a crystal of copper: Cu: 16.84X1010 Pa 012 = 12.14 x1010 Pa C44 2 7.54 X 1010 Pa 311 = 1.50 x 10’“ Pa’1 312 = —O.63 x 10'11 Pa’1 344 = 1.33 x 10‘“ Pa“1 A tensile stress 033 = 4 MPa is applied along the [001] direction. Determine the elastic strain state in the crystal. +3 “‘Qk: 33- C33 deem/{lots CUAi‘SZJ'b/Qvic—D \MQQFM‘QLQWC d2¥efnmkims VMSMW 5-:A—h: ta Aim I—C 63=LtMP1l WW EC: Sl'b 5'3 “5 “Ix-t Ovt\y ngvm Gt: @5’ 'z: p —u .( We-edect. gs: 43 5’; U ’5 C 0.69’5‘10 8; ‘> “My”: —z.§z.m*5 " 3‘ m .6. 6Z.: :31 613, =— C" DvCQ'S' £3.” Pa“) (*Mi’é) : ”2.52; ('0 page 3 / 6pages total U) MSE 564 Midterm W/2008 Anderson-B Computing yield strength and onset of necking ( 10 points) a. Based on the information in the table below, what material is expected to have the 1ar_est strain rior to neckin? Metal Stacking fault Strain-hardening Slip enery (mJ/mz) exponent n character Stainless Steel < 10 ~O.45 Planar Cu ~90 ~O 3 Planar/wavy Al Wav Values from Hertzberg, Deformation and Fracture Mechanics of Engineering Materials. Answer (a): 8‘ Seesaw. a: c 3-9—42 Pei Jr 5' b. Provide a physical explanation in words to explain why this is the case. Do not use equations to explain. ' i " See «9143wa Lt) 424cm ' , A ,j _ Estimating true strain to failure ( 10 points) A bar with an initial circular cross sectional of radius r = 6 mm is strained in tension until it fractures at a neck. The cross section of the neck is also circular, but with a radius of 3 mm and the cross section outside the neck is circular, with a radius of 5 mm. Estimate the true strain to failure in the necked region. ‘ ’Maammm‘wm“ A ”W1" Av : {We-\- 1 ,evr @ts / t,,.,w~~w—~/\w “*4 (Pm/Hail " w L Car-ediJv‘. : _,QM TV C‘OMN‘) +3 59w Gr 11» {.9 TV Cami“ ~12: -'-“ LEG} page 4/ 6pages total MSE 564 Midterm W/2008 Anderson-B Single Crystal Yield (12 points) A BCC crystal yields when the resolved shear stress acting on a {110}/<111> type slip system reaches 4 MPa. What magnitude of tension along a <100> type direction is needed to yield the crystal? 1: 1 5"2' :3 Glue-70m, «eta, ’ CT - M f [no-3‘ [(H ‘ 0in C! J < V}: [(0:93)(____r:£_jt [(093)61 ll Gil: «ET 7241:: 5” 5 \fl: (Co/<33 3 \f—L: (“FMFQ‘ Answer: Cf % M93 Strengthening mechanisms (12 points) a. The table below lists solution strengthening as one type of strengthening mechanism for metals at room temperature. Complete the left column by adding two additional types of strengthening in metals at room temperature. b. The right column indicates that solution strengthening depends on the square root of solute concentration. In a similar manner, list the functional dependence of your additional mechanisms on a relevant microstructural/material oarameter. Strengthening mechanism solution strengthening (solute _oncentration)1/2 page 5 / 6pages total MSE 564 Midterm W/2008 Anderson-B Miscellaneous True/False Questions (21 points) Circle TRUE or FALSE as appropriate for each statement below. a. If the dominant deformation mechanism in a polycrystal is grain boundary (Coble) creep, the creep rate is likely to halve if the stress is halved. FALSE b. During pr1_ _.r slip, the tensile axis rotates toward the slip plane normal. c. Whether or not an upper and lower yield point is observed in low carbon steels depends e test temperature and strain rate. TRUE d. Solution strengthening of BCC iron using substitutional atoms (such as chromium iwsmore effective than one based on interstitial carbon. Pol crystalline metals generally do not exhibit an easy glide regime (regime I) 1115? FALSE f. Texture development during rolling or drawing is generally not dependent on stacking fault energy. g. Ceramic materials are brittle at room temperature because they contain no dislocation . _ TRUE END OF EXAM page 6 / 6pages total ...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern