DISPERSED SHORT RANGE ORDER IN GOLD - SILVER ALLOYS
The diffuse intensity of X-rays was measured on two gold - silver alloys containing 50% and 75% gold respectively after annealing at 300, 250 and 200 degrees C. From these data the short range order (SRO) parameters n-RDi were calculated. It was found that these parameters increase only very slightly with decreasing temperature. In contrast are the results of measurements of the electrical resistivity which indicate that the atomic mobility in these alloys is sufficiently large to allow the observation of structural changes at temperatures as low as 100 degrees C. However, the thermodynamic equilibrium state of SRO is obtained only for temperatures as low as about 200 degrees C without irradiation. It is further found that an increase of the degree of order in the gold - silver alloys results from two processes having a rate ratio of about 10**5., one causes a decrease, the other an increase of the electrical resistivity. The evaluation of the experimental SRO parameters and the electrical resistivity leads to an atomic arrangement which is best described by the dispersed particle model in the gold - silver alloys with particle sizes of about two lattice constants.
Bibliographic Reference: ACTA METALLURGICA, VOL. 33 (1985), NO. 4, PP. 587-593
Record Number: 1989123085600 / Last updated on: 1987-01-01
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