Structural correlations between liquid and solid Ag70Au30 alloy

Through the high temperature X-ray diffraction, structural evolution of Ag
₇₀
Au
₃₀
alloy with varying temperatures has been investigated. The liquid alloy experiences a sudden structure change nearby 1150°C, which has been further thermodynamically confirmed by Differential Scanning Calorimetry (DSC). Small pre-peaks have been found in the structure factor (S(Q)) curves, indicating the stable medium range order (MRO) structure in the melt. As the temperature decreases from 1100°C to 1000°C, MRO structure gets more pronounced. Compared with the structures of Ag
₉₀
Au
₁₀
, Transmission Electron Microscope (TEM) results reveal that Ag
₇₀
Au
₃₀
alloy possesses much finer grains. It is concluded that there are strong correlations between melt and solid in Ag
₇₀
Au
₃₀
alloy, and MRO structure in the liquid favors refined solid microstructure.