The effect of aging modes on the structure and thermomechanical behavior of alloys based on titanium nickelide and bearing the same content of nickel (55.7 wt.%) and different volume fractions of the Ti2Ni phase is studied. It is shown that the morphology of the Ti3Ni4 particles precipitated in the quenched alloy as a result of aging at 450 and 550 °C and the characteristic temperatures of the martensitic transformation vary as a function of the initial content of the Ti2Ni phase.