Influence of prior low-temperature aging of Fe-Ni-V alloy martensite on property change during high-temperature aging

Presented are data on the effect the low-temperature pre-aging of the martensite in N18F7, N18F10 and N18K10F7 alloys upon the variation of the properties in subsequent high-temperature aging. The spectra of the resonance absorption of gamma-quanta and also the data on the variation of the specific electric resistance have indicated that double-aging causes a greater impoverishment of the solid solution (martensite) in vanadium and nickel. This leads to a greater volumetric proportion of the precipitations of the excessive intermetallic phase and to its greater fineness and, in consequence, to a greater degree of strengthening. In N18F10 and N18K10F7 alloys, characterized by a greater degree of supersaturation of the solid solution in vanadium (as compared to the N18F7 alloy), the double-aging has no effect upon the variation of the properties