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Unformatted text preview: s i t y and average v e l o c i t y o f m o b i l e d i s l o c a t i o n s and L
t he o b s t a c l e d i s t a n c e .
From a d i f f e r e n t k i n d o f e x p e r i m e n t van den B r i n k e t al  found t h a t a t E i n
t he same a l l o y
pL = 1 . 7 106 . £ 0 .88 . c cm-1 (12) a t room temperature.
F rom (10), (11) and (12) and using K 2 = 1 /10.2 sec, m = 1.47 it follows =0.25 .c 2 .35
c to be compared with the experimental
T he agreement seems reasonable. result ~ = 0.21 .~ 2 .4 at room temperature. 4. SUMMARY
It was assumed that inhomogeneous deformation starts when the increase of solute
c oncentration at the dislocations exceeds a critical value. From this it was derived
t hat the condition for inhomogeneous deformation in substitutional alloys depends
o n strain, aging time and temperature as described by equation (7). This condition
w as tested in a AuCu 14 alloy and found to agree with experimental results in the
c ases of first yieling, repeated yielding and serrated yielding.
A t constant temperature the Ii~ders strain Ac. was found to be the same function
o f prestraln and aglng t me for all three types of inhomogeneous deformation.
• • L R EFERENCES
8. S.H. van den Brink and P.G. Mc. Cormlck, Scripta Met. --8 (1974) 125.
A. Wijler, Thesis Delft 1972.
P.G. Mc. Cormick, Acta Met. 20 (1972), 351.
A. van den Beukel, Phys. Sta'~. Sol. (a) 30 (1975) 197.
J. Friedel, Dislocations p. 405 Oxford 19-'~4.
A. Wijler, M.M.A. Vrijhoef and A. van den Beukel, Acta Met. 2__22(1974) 13.
B.M. Korevaar, Thesis Delft 1960.
S.H. van den Brink, A. van den Beukel and P.G. Mc. Cormick, Phys. Stat. Sol.
(a) 3 0 (1975) 469. No. 6...
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- Winter '14