424 Appendix IV.Solutions to Selected Problems Chapter 6 6.1.X=-Cx=2C:-C0 X=0~Cx=Ci X=十∞Cx=C0 6.2.t→0Cx=C: t→0(x positive)Cx=Co t0(x negative)Cx 2Ci -Co 6.3.里=82.9 6.4.(a)D=1.44×10-21cm2/s;No (b)nv=1.19 x 1018 vacancies/cm3 n/ns 1.97 X 10-5 vacancies per lattice site (c)ny =3.57 X 1017 vacancies/cm3 nwns =5.92 X 10-6 vacancies per lattice site (d)Do=8.3×10-10cm2s;Yes (e)D becomes smaller 6.5.1=3.47(hr) 6.6.(a)x=4VDt;(b)x=VDt;(c)Cx0.15 Ci Chapter 8 8.1.y (austenite)52%;Fe3C (cementite)48% 8.2.2%C 8.3.Pearlite:84% Primary a:16% Pearlite contains 0.77%C Primary a contains 0.0218%C 8.4.rint =0.534 A;lattice will expand 8.5.rint =0.361 A(tetrahedral);rint =0.192 A (octahedral) 8.6.Interstitial site for y-iron is larger.Thus,higher solubility of C in y-iron.See Figure 8.1. 8.7.Atomic radius is larger for higher coordination number. Chapter 9 9.1.0.05917 (note difference between In and log!) 9.2.E=0.68(V) 9.3.Cion=0.0445M m=2.829(g) 9.4.P-B-ratio 1.75 (between 1 and 2 continuous and adherent) 9.5.P-B-ratio 1.58 (stable oxide) 9.6.W=2.96(g) 9.7.t=756.3(s)=12.6(min)(forn=1) t=2,269(s)=37.8(min)(forn=3) Chapter 11 11.1.0.1(V) 11.2.2.73×1022 electrons or1.07 electrons cm3 atom6.1. X
 " Cx
2Ci  C0 X
0 Cx
Ci X
" Cx
C0 6.2. t
" Cx
Ci t
0 (x positive) Cx
C0 t
0 (x negative) Cx
2Ci  C0 6.3.
82.9 6.4. (a) D
1.44 1021 cm2/s; No (b) nv
1.19 1018 vacancies/cm3 nv/ns
1.97 105 vacancies per lattice site (c) nv
3.57 1017 vacancies/cm3 nv/ns
5.92 106 vacancies per lattice site (d) Dv0
8.3 1010 cm2/s; Yes (e) D becomes smaller 6.5. t
3.47 (hr) 6.6. (a) x
4Dt; (b) x
Dt; (c) Cx
0.15 Ci 8.1.  (austenite) 52%; Fe3C (cementite) 48% 8.2. 2% C 8.3. Pearlite: 84% Primary : 16% Pearlite contains 0.77% C Primary  contains 0.0218% C 8.4. rint
0.534 Å; lattice will expand 8.5. rint
0.361 Å (tetrahedral); rint
0.192 Å (octahedral) 8.6. Interstitial site for -iron is larger. Thus, higher solubility of C in -iron. See Figure 8.1. 8.7. Atomic radius is larger for higher coordination number. 9.1. 0.05917 (note difference between ln and log!) 9.2. E
0.68 (V) 9.3. Cion
0.0445 M m
2.829 (g) 9.4. P-B-ratio
1.75 (between 1 and 2 continuous and adherent) 9.5. P-B-ratio
1.58 (stable oxide) 9.6. W
2.96 (g) 9.7. t
756.3 (s)
12.6 (min) (for n
1) t
2,269 (s)
37.8 (min) (for n
3) 11.1. 0.1 (V) 11.2. 2.73 1022  ele c c m tro 3 ns  or 1.07  ele a c to tr m ons  fg fv Chapter 6 424 Appendix IV • Solutions to Selected Problems Chapter 8 Chapter 9 Chapter 11