The thermodynamic properties of intermetallic compounds and solid solutions of $\mathrm{Cu}\mathrm{Zr}$ system

The thermodynamic properties of crystalline copper–zirconium alloys are investigated in a wide range of temperatures of $701$–$1740$ K and compositions of $5.1$–$97.3$ at. $\%\mathrm{Zr}$ using the Knudsen method of mass-spectrometry, including the technique based on the initiation and study of equilibria involving volatile products. The equilibrium of zirconium with $\mathrm{KF}$ additives is studied to achieve minimal temperatures of measurements. The obtained data are used to produce, for the first time, a complete thermodynamic description of all intermetallic compounds, as well as solid solutions of copper in bcc-$\mathrm{Zr}$, in the range from temperatures of crystallization of amorphous alloys to liquidus temperatures. The accuracy and reliability of the obtained thermodynamic functions are confirmed by the coincidence of the results of measurements in studying samples of different compositions under different experimental conditions (the material of the effusion cell, the size of the effusion orifice, the type of reaction additive), as well as by agreement of the results with one another and with independent experimental data on phase equilibria. The evidence of the existence of $\mathrm{Cu}_2\mathrm{Zr}$ and $\mathrm{Cu}_5\mathrm{Zr}_8$ phases is obtained, and the regularities of phase transformations in crystalline copper–zirconium alloys are revealed.