Enthalpy of formation of intermetallic phases from Al–Ni and Al–Ni–Ti systems

Abstract

The formation enthalpy of binary AlNi and AlNi3 and ternary Al2NiTi, AlNiTi and AlNi2Ti intermetallic phases was determined by the solution calorimetric method. The phases were prepared by the levitation technique and by melting metals in a glove-box operating with high purity argon. After the preparation, all phases were identified by X-ray diffraction (XRD) and the quantitative analysis was performed by means of a scanning electron microscope (SEM EDS). The formation enthalpies measured at room temperature for the binary and ternary phases are as follows: −66.3 ± 1.7 kJ/mole of atoms for AlNi, −40.5 ± 1.6 kJ/mole of atoms for AlNi3, −40.7 ± 1.8 kJ/mole of atoms for Al2NiTi, −56.9 ± 1.1 kJ/mol of atoms for AlNiTi and −72.1 ± 1.2 kJ/mole of atoms for AlNi2Ti.Additionally, for the AlNiTi phase, the measurements were conducted at the temperature of 1133 K and the determined formation enthalpy was found to equal −56.5 ± 2 kJ/mol of atoms. The very near values obtained at room and elevated temperature point to the fact that it is independent of temperature.