抄録
The phase diagram of Pt rich Cu–Pt alloy system containing several kinds of superlattice was explained by Bragg Williams’ approximation by taking the first as well as second neighbor interactions into account, in which the ratio of interactions was determined to be V2⁄V1=3. Next, the observed atomic diffuse intensity obtained by electron diffraction photograph was analysed numerically and the atomic short range order parameters and the atomic pair interactions were determined, where the convergence was guaranteed within the several neighbors. The observed diffuse pattern was well reproduced by the calculated results. The ratio of main pair interactions was obtained to be V1:V2:V3:V4\simeq1:3:0.4:−2.6, and the phase diagram mentioned above was well described by these values. Some origins of the pair interactions were discussed.
