Experimental investigation of the phase equilibria of the La-Ti-Zn system at 600 and 450 °C

A series of La-Ti-Zn alloys was designed to investigate the 600 and 450 °C isothermal sections of the La-Ti-Zn system based on examination by scanning electron microscope (SEM) equipped with energy dispersive X-ray spectrometer (EDS) and X-ray powder diffraction (XRD). No ternary compound was found in the system. Nine three-phase regions were identified at both the 600 and 450 °C sections. Five Ti-Zn intermetallic compounds, TiZn16, Ti3Zn22, TiZn3, TiZn and Ti2Zn were observed in the present work. It was found that TiZn3 may not be a strictly stoichiometric compound. La does not dissolve in any of Ti-Zn binary compounds and the solubility of Ti in La-Zn binary compounds was ≤ 0.3 at%. The TiZn3 phase can equilibrate with LaZn13, LaZn11, La2Zn17, and La3Zn22, while TiZn can achieve equilibrium with La3Zn22, LaZn5, LaZn4, and LaZn2.