Enthalpy of Formation of Intermetallic Phases from Fe-Ni-Ti System. Comparative Studies / Entalpia Tworzenia Faz Międzymetalicznych Z Układu Fe-Ni-Ti. Studia Porównawcze

The solution calorimetric method was used for the measurement of the formation enthalpy of the binary FeTi and Fe2Ti intermetallic phases and of the FeNiTi2 phase from the region of the ternary B2 one. The FeNi and FeNiTi2 phases were prepared by levitation melting and the Fe2Ti phase - by melting the metals in a glove-box under high purity argon. The alloys obtained were identified by the X-ray diffraction analysis. The structural study of the alloys with the composition equal to the FeTi and Fe2Ti phase confirmed the mentioned phases mainly in the samples. In the case of the ternary alloy of the composition of the FeNiTi2 phase, a slight amount of iron was also found. The obtained values of the formation enthalpy equal as follows: -27.2±1.3 kJ/mole of atoms, -22.5±1.4 kJ/mole of atoms and -34.2±1.3 kJ/mole of atoms for the Fe2Ti, FeTi and FeNiTi2 phase, respectively.