Enthalpies of formation of compounds in Al-Ni-Y system

The enthalpies of formation of the ternary compounds Al 4NiY, Al 2NiY, Al 2Ni 6Y 3, Al 16 Ni 3Y, AlNiY, Al 3Ni 2Y, AlNi 8Y 3, Al 7Ni 3Y 2, and of the binary compounds Al 2Y containing nickel and Ni 5Y containing aluminum have been determined by high temperature reaction calorimetry. The enthalpy values measured are compared to previously published results where available as well as extended Miedema model predictions. The melting points of the compounds were determined by DTA and X ray diffraction was used to confirm the crystal structures of the compounds. The enthalpies of formation of the ternary compounds show a maximum along the 50%Al (mole fraction) section. The ternary compounds appear along lines of constant yttrium content consistent with binary compound solubility extensions.

The enthalpies of formation of the ternary compounds Al_4NiY, Al_2NiY,Al_2Ni_6Y_3, Al_(16)Ni_3Y, AlNiY, Al_3Ni_2Y, AlNi_8Y_3, Al_7Ni_3Y_2, and of the binary compoundsAl_2Y containing nickel and Ni5Y containing aluminum have been determined by high temperaturereaction calorimetry. The enthalpy values measured are compared to previously published resultswhere available as well as extended Miedema model predictions. The melting points of the compoundswere determined by DTA and X-ray diffraction was used to confirm the crystal structures of thecompounds. The enthalpies of formation of the ternary compounds show a maximum along the 50 percentAl (mole fraction) section. The ternary compounds appear along lines of constant yttrium contentconsistent with binary compound solubility extensions.