Structural properties and evolution in the solidification process of Cu–Ag alloys

The atomic structures of liquid Cu–Ag alloys (Cu₈₀Ag₂₀, Cu₆₀Ag₄₀, Cu₄₀Ag₆₀ and Cu₂₀Ag₈₀) have been investigated in the solidification process by means of X-ray diffraction. The results show that the liquid structures of Cu–Ag alloys, which are micro-homogeneous and similar with their solid state, display quite stable changes on a large-scale range indicated by the correlation radius r_c, although the short-range order structures change obviously around their liquidus (liquid–solid transformation). This is different from the results of the In₃₀Sn₇₀ alloy we previously reported, which shows an abrupt structure changes around its liquidus. In addition, the Gaussian peaks decomposition of the radial distribution functions (RDF(r)) was also performed to shed light on the element distribution and structure evolution in the whole solidification process especially around the liquidus.