Phase relations in the Gd-Ni-Al ternary system have been established for two isothermal sections (500 and 800°C) based on X-ray powder diffraction analysis (XRD), Light Optical Microscopy (LOM), Scanning Electron Microscopy (SEM) coupled with Energy dispersive Microprobe Analysis (EPMA) on about 31 annealed alloys in the 50 - 100 at.% Al region. Seven intermetallic phases have been identified in samples annealed at 500°C and 800°C: Gd3Ni5Al19 (oS108-Gd3Ni5Al19), Gd4Ni6Al23 (mS66-Y4Ni6Al23), GdNiAl4 (oS24-YNiAl4), GdNiAl3 (oP20-YNiAl3), Gd3Ni7Al14 (hP72- Gd3Ni7Al14), GdNiAl2 (oS16-CuMgAl2) and GdNi2Al3 (hP18 GdNi2Al3). One additional ternary phase GdNi3Al9 (hR78-ErNi3Al9) has been found only in samples annealed at 800°C. The isothermal sections have been determined and then compared, the crystal structures of the ternary phases have been confirmed and lattice parameters calculated.
The Gd–Ni–Al system: phases formation and isothermal sections at 500°C and 800°C
DELSANTE, SIMONA;BORZONE, GABRIELLA
2014-01-01
Abstract
Phase relations in the Gd-Ni-Al ternary system have been established for two isothermal sections (500 and 800°C) based on X-ray powder diffraction analysis (XRD), Light Optical Microscopy (LOM), Scanning Electron Microscopy (SEM) coupled with Energy dispersive Microprobe Analysis (EPMA) on about 31 annealed alloys in the 50 - 100 at.% Al region. Seven intermetallic phases have been identified in samples annealed at 500°C and 800°C: Gd3Ni5Al19 (oS108-Gd3Ni5Al19), Gd4Ni6Al23 (mS66-Y4Ni6Al23), GdNiAl4 (oS24-YNiAl4), GdNiAl3 (oP20-YNiAl3), Gd3Ni7Al14 (hP72- Gd3Ni7Al14), GdNiAl2 (oS16-CuMgAl2) and GdNi2Al3 (hP18 GdNi2Al3). One additional ternary phase GdNi3Al9 (hR78-ErNi3Al9) has been found only in samples annealed at 800°C. The isothermal sections have been determined and then compared, the crystal structures of the ternary phases have been confirmed and lattice parameters calculated.
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