Nucleation of secondary defects in quenched gold and zinc-doped gold

Self-wave processes in a wide-aperture laser with an additional nonlinear component

“…Considering first the observations on quenched metals, we have seen from the results presented in $ 2 that SFT nucleation occurs in quenched gold containing around vacancies at temperatures as low as 250K (Hussein and Dodd 1971). This compares with the temperature range for stage I11 recovery in electron irradiated gold of 20&350K, with the peak temperature decreasing as defect concentration increases.…”

“…In particular, lowering the quench temperature and/or increasing impurity levels results in the clusters becoming both dispersed on a finer scale and smaller until they appear as small black spots down to 20 A diameter (eg Cotterill 1961, Cotterill andSegall 1963) Annealing experiments on these defects show that they coarsen to form resolvable SFT and since there are no discontinuities in the annealing curves it is reasonable to conclude that the black spot defects are small SFT (Yoshinaka et a1 1968). Furthermore, Frank loops are observed but only after rapidly heating quenched specimens to tem- peratures greater than 373 K , Hussein and Dodd 1971. In a detailed study of the formation of SFT and Frank loops Hussein and Dodd used a double ageing technique similar in concept to that used previously by Kiritani to study loop formation in quenched aluminium (Kiritani 1965, Kiritani et ai 1969.…”

“…The temperature profile typically used in this type of experiment is shown schematically in figure 2 in which To is the quenching temperature, Temperature K Figure 4. Graph showing the proportion of defects in the form of Frank loops as a function of initial ageing temperature (from Hussein and Dodd 1971). TA, the initial ageing temperature and TAF the final ageing temperature.…”

“…With regard to the influence exerted by impurities, the experimental evidence has shown that SFT are heterogenously nucleated even in the purest gold studied (eg Cotterill and Segall 1963, Meshii 1965, Meshii et a1 1966, Siege1 1966, Johnston et al 1968, Quader and Dodd 1968, Yoshinaka et al 1968. Hussein and Dodd 1971.…”

“…Referring to the schematic diagram in figure 2, Kiritani carried out the initial ageing of quenched specimens at TA, in the range 183 K -, 303 K and final ageing at TAF in the range 273 K + 373 K. An examination of the results presented in the two papers (Kiritani et a1 1969) leads to the conclusion that the apparent loop nucleation rate increases with decreasing TAI until a maximum is reached at about 253 K, where loop nucleation occurs extremely rapidly with saturation in C, being achieved after ageing for times of about 1 s. At temperatures below 253 K the nucleation rate falls away rapidly. The results are illustrated schematically in figure 6 in which the apparent loop nucleation rate is plotted Graph showing schematically the nucleation rate of secondary defects as a function of ageing temperature expressed as a fraction of the melting temperature in quenched aluminium (full curve) and gold (dotted curve) constructed from data by Hussein and Dodd (1971) and by Kiritani et al(1969).…”