X-ray diffraction study of the Y-[Ti, Cr, Zn, Hf]-Ga system alloys

Alloys of the Y-(Ti, Cr, Zr, Hf)-Ga systems were analyzed by the X-ray diffraction methods. Isothermal cross-sections of phase diagrams for these systems at 800 (Y-(Ti, Zr, Hf)-Ga) and 700 deg C (Y-Cr-Ga) were plotted. The Y-Ti-Ga system is characterized by formation of two ternary compounds (YTi2Ga4, Y4TiGa3), the Y-Cr-Ga system - of one compound (Y2CrGa5), the Y-Zr-Ga system - of two compounds (approximately YZrGa3, Ysub(4.4)Zrsub(0.6)Gasub(3)), the Y-Hf-Ga system - of one compound (Ysub(1.5)Hfsub(0.5)Gasub(3)). Crystal structure for YTi2Ga4 and Y2CrGa5 was determined by the Debye-Scherrer method. The former compound crystallizes as the YbMo2Al4 structural type (tetragonal lattice with a=0.6712 nm, c=0.5484 nm), the latter - as the AuCu3 type (a=0.4289 nm). Approximately YZrGa3 and Ysub(1.5)Hfsub(0.5)Gasub(3) compounds are stabilized solid solutions on the base of Y2Ga3 compound, which is stable only above 800 deg C. In crystallochemical respect the Y-Ti-Ga system is similar to the Er-Ti-Ga system