Jialin Yan

The 500°C isothermal section of the Al–Dy–Ti ternary system

Abstract The phase relations in the Al–Dy–Ti ternary system at 500°C were investigated by powder X-ray diffraction (XRD), differential thermal analysis (DTA), optical microscopy and scanning electron microscopy (SEM) techniques. The existence of two ternary compounds DyTi 2 Al 20 and Dy 6 Ti 4 Al 43 were confirmed. The 500°C isothermal section of this ternary system consists of 14 single-phase regions, 27 two-phase regions and 14 three-phase regions. At 500°C, the maximum solid solubilities of Ti in Dy 2 Al, Dy 3 Al 2 and DyAl 2 is about 2.1at.%, 3.6at.%, 16.5at.%, respectively, and that of Dy in Ti, Ti 3 Al, TiAl is less than 1at.%.

Phase relationship in the Gd-Ti-Al ternary system at 500°C

The phase relationship in the Gd-Ti-Al ternary system at 500°C was investigated by powder X-ray diffraction (XRD), differential thermal analysis (DTA), optical microscopy and electron probe microanalysis (EPMA) techniques. The 500°C isothermal section of this ternary system consists of 14 single-phase regions, 27 two-phase regions and 14 three-phase regions. At 500°C, the maximum solid solubilities of Ti in Gd2Al, Gd3Al2 and GdAl2 is 2.0 at.%, 3.5 at.%, 16.3 at.%, respectively and that of Gd in Ti, Ti3Al, TiAl is less than 1 at.%.

Structural and magnetic properties of DyCo4―xFexGa compounds

The structural and magnetic properties of the DyCo 4− x Fe x Ga compounds with x =0, 0.5, 1, and 1.5 have been investigated by X-ray diffraction and magnetic measurements. Powder X-ray diffraction analysis reveals that each of the DyCo 4− x Fe x Ga compounds has a hexagonal CaCu 5 -type structure (space group P 6/ m m m ). The Fe solubility limit in DyCo 4− x Fe x Ga is x x , the larger the unit-cell parameters a , c , V , and the 3 d -sublattice moment but the smaller the 3 d uniaxial anisotropy. Magnetic measurements show that the Curie temperature of DyCo 4− x Fe x Ga increases from 498 K for x =0 to 530 K for x =1.5, the compensation temperature T comp decreases from 286 K for x =0 to 238 K for x =1.5, and the spin-reorientation transition temperature increases from 403 K for x =0 to 530 K for x =0.5. No spin-reorientation transition was found in the samples with x =1.0 and 1.5. The saturation magnetization of DyCo 4− x Fe x Ga measured at 173 K increases but the magnetization measured at 300 K decreases with increasing Fe content x .

New diffraction data and crystal structure of HoCo 0.67 Ga 1.33

Compound HoCo 0.67 Ga 1.33 was synthesized and studied by means of X-ray powder diffraction technique. HoCo 0.67 Ga 1.33 was found to have the orthorhombic CeCu 2 structure (space group I m m a ) with a =4.3479(2) A, b =7.0351(3) A, c =7.4876(3) A, Z =4, and D calc =8.62 g/cm 3 . The crystal structure of HoCo 0.67 Ga 1.33 was also refined by the Rietveld method. Ho atoms were found to occupy the 4 e positions and mixed Co/Ga atoms to share the 8 h positions of the space group I m m a (No. 74).