Nanostructural evolution in films of alloy Zn90Al7Cu3

The phase decomposition and structural changes in Zn–Al based alloy films (Zn90Al7Cu3 in wt.%) were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. Alloy films were produced by using an electron beam deposition technique. It was found that the supersaturated nanophase possessed a strong preferred crystal orientation (0001). The decomposition of the nanophase ηn′ started with clustering to form zones and a transitional phase, which was accompanied by an eutectoid decomposition, ηn′→βeut′+T′+ηeut′. The nanophase βeut′ decomposed to form zones and transitional phases during prolonged ageing. The mechanism of the formation of the zones and the nanophase stability are discussed.