The Y–Ni–Cu ternary system at 600°C

The isothermal section of the Y-Ni-Cu phase diagram at 600°C has been investigated by means of X-ray diffraction and microstructure analyses.The homogeneity ranges of the solid solutions YNi 5-х Cu х (0 ≤ х ≤ 4.6) (structure type CaCu 5 , space group P6/mmm a = 0.48861(2)-0.50080(4),c = 0.39592(2)-0.40740(4)nm), Y 2 Ni 17-х Cu х (0 ≤ х ≤ 7.8) (structure type Th 2 Ni 17 , space group P6 3 /mmc, a = 0.8314(1)-0.8387(1),c = 0.8042(1)-0.8117(1)nm), YCu 6-7 Ni x (0 ≤ х ≤ 0.28) (structure type TbCu 7 , space group P6/mmm, a = 0.49470(4)-0.49540(4),c = 0.4133(4)-0.4227(4)nm) were refined.It was found that the maximal solubility of the third component does not exceed 3.8 at.% in Y 2 Cu 7 and less than 1 at.% in Y 2 Ni 7 , YCu, and YCu 4 .The crystal structure of a single crystal of composition YNi 4 Cu (YNi 5-х Cu х solid solution) was investigated by X-ray diffraction: a = 0.4899(2), c = 0.3979(3) nm, R 1 = 0.028 for 57 independent reflections with I o ≥ 2σ(I o ), wR 2 = 0.058.A new ternary compound, YNi 2.85-0.75Cu 1.15-3.25 , of unknown structure with an extended homogeneity range, was found.Intermetallics / Rare-earth metal system / Phase diagram / X-ray diffraction