Chemical short-range order in liquid Ni-Cu

Abstract

Neutron diffraction in combination with isotopic substitution on the zero-scatterer⁶²Ni₄₃⁶³Cu₅₇shows indications for chemical short-range order in the stable liquid as evidenced by oscillations in the concentration-concentration structure factorS_CC(q). This points towards a non-ideal solution behavior of Ni-Cu contrary to common believe but in agreement with measurements of free enthalpy of mixing. The temperature dependence ofS_CCat small momentum transfer provides evidence of critical compositional fluctuations in Ni₄₃Cu₅₇melts.

Keywords: demixing; neutron diffraction; short-range order of liquids.