Qgb mole mole

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4             .                         10 µm >        @ >        @           >                                               >        .1
                                                                                          @                                                 (
                                   =Coble              Nabarro-Herring                                   >                         (
                                                            Strain rate (s-1)
                                    Stress             T = 1700 K                             T = 1810 K
                                   (MPa)
                                       10                2.0 x 10-8        7.0 x 10-8
                                       20                4.0 x 10-8        1.4 x 10-7
                                       30                6.0 x 10-8        2.1 x 10-7
                                                                  -8
                                       40                8.0 x 10          2.8 x 10-7
                                       50                2.3 x 10-7        8.0 x 10-7
                                                                  -7
                                       60                5.0 x 10          1.8 x 10-6
                                       70                9.9 x 10-7        3.5 x 10-6
                                                                  -6
                                       80                1.8 x 10          6.3 x 10-6
                                       90                3.1 x 10-6        1.1 x 10-5
                                      100                4.9 x 10-6        1.7 x 10-5
                                                       .       >>                                                                 > .2
4   > >           >> @       >                        > Nabarro-Herring Coble                                                      (
                                                                      .     >      >.                                 @
      .                  K           <10 µm >          @ N-H Coble                                                   >             (
       @ > >                        >@                                                        >           >                        (>
    @ > >                >                 <                 @                                             :             ).
                                                                                                                (.>
                                                             >                    >               >@                               (>
                                                                                                                =>


                                                                         Bulk Diffusion                      Grain Boundary
                                                                                                                Diffusion
                                                                          Qbulk=184600                       Qgb=20200 J/mole
                                                                             J/mole
                                                                           D0=40mm2/s                          D0=0.3 mm2/s
                                                                              KN-H=10                           W=0.25nm
                                                                                      Dv Ω σ                             Dgb    wΩσ
                                                                         ε& = K 2        .                ε& = K 1            .
                                                                                      d 2 kT                              d 3    kT
                          >                 >                     S.S.304                   >                       .3
3                       @ > >                   @>                                         @         .>    >
                                                          @       @ >.                              10000psi
                                                                                       .            1100 0 F
                                                           > @            @ > >      > >
                                                      >    @               .> 5000psi
                                                                             >        > S.S.304
                                                                      m
                                                       ε&     σ           − H
                                                           = 
                                                             σ      exp(
                                                                               )
                                                      ε& 0    0            kT
                                                      < m = 8 < σ 0= 62 psi       >                            >
                                                      k = 6.79 × 10 −23 in − lb / 0R       < H = 5.85 × 10 −18 in − lb
                                :               > >                                          >     . 0 R = 0 F + 460
    E RT = 29 × 10 6 psi , E11000F = 22.3 × 10 6 psi


       >           =>       >       >                                         >@                >                   .4
2
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           .   >            10 8        >                                      >            >                       .5
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