Experimental investigation of the Cu–Ti–Zr system at 800 °C

The Cu–Ti–Zr system has attracted increasing interest in recent years due to its good glass-forming ability and the use of its alloys as active brazing filler metals. However, only limited phase diagram data are available in the literature. In the first part of this work we describe experimental investigations. Samples were investigated by means of EPMA and DSC. At 800 °C an isothermal section was determined by the diffusion couple technique and individual alloy compositions. This combination of methods is deemed to be effective, as it only involves limited experimental effort. The binary systems Cu–Ti and Cu–Zr show a series of intermetallic phases. One of these – Cu(Ti,Zr)2 – forms an isomorphous solid solution. The binary phases in the Cu–Zr system, in particular Cu51Zr14, show remarkable solubility for Ti. One ternary compound (Cu2TiZr) in this system is known to be in thermal equilibrium with nearly all binary intermetallic phases and therefore dominates the isothermal section. Based on current data and data in the literature a thermodynamic description of the Cu–Ti–Zr system was obtained which is described in the second part of this work.