This preview shows pages 1–8. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: E45 First Exam
October 7, 2009 8 CL TMUE’ Point Values of Problems 1. 14
2. 16
3. 25
4. 25
5. 20 Z= atomic number
R= gas constant = 198? cal/moleK
0K = 273°C Formulae for E45 Exam #1
o = FIAO
s = (l. — lo)r’lo
ET = ln_(l.llo)
0 2 Es
v = 4,45}.
%RA = {(A0 — Arm} 100%
E = A}'r + Bfr"
ET = Ind/10)
A = (Zle)(Zze)f4‘ztso
Young’s Modulus ~ dzEfdrz
X = C(IE — AE)
%ionic = {Iexp[(0.25)(XA  X3)2]}x100
(th) {hkl} [ijk] <ijk>
APF = (Vol of atoms in unt cell)f(vol of unit cell)
LD = (# of atoms centered on direction vector);’(length of direction vector)
PD = (# of atoms centered on plane)! (area of plane)
dth = 8.3012 + 18 + 12)”2
NV = chp(QvaT) Wu 2 (C0 _ CByICu— CB) 1. The engineering stressstrain curve of an unknown metal was measured by a tensile
test and is presented in the following ﬁgure. The linear region terminates at a strain of
0.005 and the curve exhibits a slope of zero at a strain of 0.20. (D ms Engineering
Stress 0 ID i
® 01' Engineering Strain (a) Identify the following regions and parameters on the diagram: elastic region; plastic
region; 0.2% offset yield stress; ultimate tensile stress (b) A second identical sample is subjected to the same tensile test except the test is
stOpped when the stress reaches the ultimate tensile strength. The gauge length of the cylindrical sample is 5 cm and the sample’s diameter is 0.5 cm. Calculate the gauge
length of the sample after it is removed from the tensile test machine. A0,: skulh — Blaslti Skitibia All 2 (0.20— 0,935,,“ = 0.97:9.“ heel gem3t: lemul'k“ 59M swan?»
': 5.9chm 1th @®®@ 2. The energy versus distance of atomic separation of two unknown solids is presented in the following ﬁgure.
(3) Which solid, A or B, has the higher melting temperature? 9 (b) Which solid has the higher coefﬁcient of thermal expansion? (c) Which solid has the higher modulus of elasticity? ll (d) Based on the shapes of the two curves is it possible to identify the type of primary
bonding (metallic, ionic, covalent) exhibited by the solids? N0 Energy 3. The most densely packed plane in the body centered cubic crystal (bcc) structure
is {1 10}. The most densely packed direction in bcc is <1 I 1>.
(3) Sketch the (110) and the [I 1 l] in the unit cube presented below. (b) For the bcc structure, calculate the number of atoms per unit area on 110.
{ } a fr; ﬁcm‘neﬂ Wm col (aloe "ml" M
Tu 1th (c) For the bee structure, calculate the number of atoms per unit length in <1 11>. Hus. «k WW“ ’1’“? ‘ I {5 ‘ﬂgibm dank (‘9an
@ meax MSI‘H 1: /2_ (2) + 1 : Z
Mlun3<w> /v\J—{'Q Wok
Ihghvg (“be 41¢.ng 4. ldentify the second element, X, in each of the three AlX phase diagrams.
Veg: brieﬂx, explain your reasoning. Element CﬂStﬂl Structure Al
Ge
Zn
Si Al fcc 0.182nm
diamond cubic 0.152nm
hep 0.153nm
diamond cubic 0.146nm %X> $©AV: 7 JANhm . c' beech Table 4 50 _
6. mm a. 5:01.!“ fh‘oe Jeajrm atomic radius priming: valence Electronegativig: 1.82
2.01
1.65
1.90 Numbers correspond to atom
percent of element X 2.8 30 %X— > e a m cabwt?”
W ioU'i’fx Shank! aria”. @ 51M Ga Ma v'dlﬂqigV61—4M‘Lr‘e
swimmith bondd, WLLLii‘M staged: {and /v' @ Z
so 2“ Simon. fl seine} t .' f»;
("MV; $43“? ins2n 1‘5 (Sinai exh; far is m chub? WM“ "‘1
r}: SheLtd dig SCIUC MAL. i5 lager S“ M 6'“: aS'Ge tin Inf(i7 {L[ {a iarjer
5mm” “not was dots/H
441cm imr 5. Elements A and B form a binary eutectic phase diagram.
(a)Using the following information construct the A—B phase diagram. The melting
points of A and B are 700°C and 600°C, respectively. Pure A and pure B form the a and [3 phases, respectively. The maximum solubility of B in (1 is 20 atomic percent
(afo). The maximum solubility of A in B is 30 21/0. The eutectic composition is 40%8
and the eutectic temperature is 500°C. At 400°C: the solubility of B in or. is 10 a/0;
the solubility of A in B is 15 aIO. Show on your diagram each of the previous pieces of information. k@
(b) At equilibrium, what phases are present at 400°C in an alloy that contains
30%B? Calculate the relative amounts of each phase that is present at 400°C. Sr = a £3: , 0.??53
0i 35110 H”
as? 1mg roam
, ‘50in _. 20
 far role?—
2 ESEr10 ...
View
Full
Document
This note was uploaded on 02/12/2011 for the course E 45 taught by Professor Gronsky during the Fall '08 term at University of California, Berkeley.
 Fall '08
 GRONSKY

Click to edit the document details