Ag—52 at.% Cu films were prepared by coevaporation onto 0.005 in. thick vitreous silica plates held at liquid-nitrogen temperature. The interference function I(K), where K=4π sinθ/λ, was evaluated from the elastic x-ray scattering of the film and compared with I(K) of the liquid alloy, measured at 1000°C, and with a model I(K) based on fcc microcrystals containing 125 atoms. The Fourier transforms of K[I(K)—1] yielded the reduced distribution functions G(r) =4πr[ρ(r)—ρ0]V(r), where ρ(r) is the weighted atomic density at a distance r from any reference atom, ρ0 is the average atomic density, and V(r) is the size factor of the diffracting domains. Both I(K) and G(r) indicate that the alloy film cannot be characterized as amorphous but is micropolycrystalline with fcc structure. The size of the microcrystals can be estimated from G(r), i.e., from the value of r beyond which G(r) is zero within the scatter of the experimental points. A value of less than 16 Å has thus been found. I(K) and G(r) of the liquid alloy are characteristic of the close-packed liquid metals with a distance of less than 15 Å beyond which no short-range order can be detected.

Amorphous films of AgCu and CuMg2, approximately 3000 A in thickness, were prepared by co-evaporation of Ag and Cu, and Cu and Mg, respectively, onto 25 #m thick Be sheets, held at liquid nitrogen temperature. Mo K~ X-rays were used as a radiation probe to determine the structure of the films, at room temperature, and of the liquid alloys of Cu with 50 at.~ Ag and with 0 and 67 at.~o Mg at 50°C above the liquidus temperature. With the transmission technique, the interference functions (or structure factors) I(K) were determined in the range of K=4rt sin 0/2 between 0.8 A -1 and 12.5 A-1, and then Fourier transformed to obtain the radial distribution functions (RDF). The I(K) and RDF of the amorphous AgCu and CuMg2 films were compared with those of the liquid Ag-Cu and Cu-Mg alloys, respectively. It was found that the structures of the amorphous and liquid Ag-Cu alloys were similar with a more well-defined short-range order occurring in the solid alloys, whose I(K) exhibited the well-known shoulder on the second peak. The I(K) and RDF of the amorphous CuMg2 and the liquid Cu-Mg alloys cannot be explained by a common structure, although I(K) showed a small premaximum below the first main peak in both the amorphous and liquid alloys, a feature observed in many liquid Mg alloys.

Mo-Ka X-rays have been used as a radiation probe to evaluate the interference functions / (K) (also called structure factors) of liquid Ag, Cu and Ag-Cu alloys with 16.5, 28, 37, 50, 57, 71 and 85 at.% Cu at temperatures about 50 °C above the liquidus. Employing the transmission technique, I(K) has been determined in the range of K = 4 n sin 0/X between 0.8 and 12.5 A -1 . The partial interference functions Iij(K) have been calculated, and it was found that the assumption of concentration independence of Iij(K) yielded reduced partial distribution functions Gij(r), the weighted sum of which were in excellent agreement with G{r), the Fourier transform of F(K) =K[I(K) -1]. The position of the first peak in G(r) and the coordination number 7] show a positive deviation from a straight line when plotted as a function of concentration.

X-rays (MoKα) have been used as a radiation probe to evaluate the interference functions I(K) (or structure factors) of liquid Cu, Mg and Cu-Mg alloys with 49, 66, and 86 at. % Mg at temperatures about 50°C above the liquidus. Employing the transmission technique, I(K) has been determined in the range of K = 4π sin Θ/λ between 0.8 A-1 and 12.5 A-1. All I(K) of the alloys exhibit a premaximum at K = 1.5 A-1.The partial interference functions Iij(K) have been determined, and it was found that the assumption of concentration independence of Iij(K) yielded reduced partial distribution functions Gij(r), the weighted sum of which were only in fair agreement with G(r), the Fourier transform of F(K) = K[I(K)-1].The positions, r, of the first peak in G(r) and the coordination number, η, determined from the radial distribution function 4π r2 ρ(r) = r G(r) + 4πr2 ρo, where ρo is the average atomic density of the alloy, show a negative deviation from a straight line when plotted as a function of concentration, which might be considered as evidence for the existence of short-range order in the liquid. Art. 2288