Transformation of precipitated phases in Zr50·5Cu34·5−xNi4Al11Agx alloy master ingots with adding Ag

AbstractThe transformation of precipitated phases of Zr50·5Cu34·5−xNi4Al11Agx alloy master ingots with Ag substitution of Cu was studied in detail by phase analysis. The precipitated (Zr–Cu) rich phases deteriorate the glass forming ability (GFA) of Zr50·5Cu34·5Ni4Al11. Two new (Zr–Cu) rich phases, A1 with bcc structure and a = 0·339 nm and A2 with fcc superlattice structure and a = 1·21 nm, were identified by a transmission electron microscope. When x = 2, A1 phase disappears, and A2 phase remains and is suppressed gradually with further Ag addition. When x = 13, one precipitated phase with Ag more than 13 at-% begins to deteriorate GFA. In the view of chemistry, the precipitation of (Zr–Cu) rich phases means that the interaction between Cu and Zr atoms is rather drastic. The addition of Ag weakens the interaction between Cu and Zr. The similar competition mechanism proposed by the authors plays an important role in suppressing precipitated phases and improving GFAs.