Precursor behavior in structure factors of AuCd alloy observed by different wavelength X-ray

X-ray diffraction intensities from single crystals of Au50.5Cd49.5 alloy have been measured at various temperatures above the martensitic transformation into ζ′2 phase. With the CuKα radiation, the diffraction intensities decrease sharply with decreasing temperature toward the transformation temperature, while no such decrease is observed with MoKα radiation. Those observations suggest precursor behavior occurring in surface regions.