Development of new methods for studying the decomposition in aging invars

N30K10T3 and N28K10T3 invar alloys are studied. After water quenching from 1150°C, they consist of supersaturated solid solutions, which can decompose in aging in the temperature range 500–700°C with the precipitation of intermetallic Ni3Ti nanoparticles. It is shown that the decomposition can be controlled by measuring the magnetic (first harmonic amplitude, phase angle φ shift, magnetic susceptibility μ) and electric (electrical conductivity σ) parameters as functions of the isothermal holding time at various aging temperatures. The alloys are studied in the following three initial states: after quenching, phase transformation-induced hardening (γ → α → γpt), and cold (20°C) plastic deformation by 30%.