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

Abstract

The solution calorimetric method was used for the measurement of the formation enthalpy of the binary FeTi and Fe 2 Ti intermetallic phases and of the FeNiTi 2 phase from the region of the ternary B2 one. The FeNi and FeNiTi 2 phases were prepared by levitation melting and the Fe 2 Ti 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 Fe 2 Ti 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 Fe 2 Ti, FeTi and FeNiTi 2 phase, respectively.