The mass percentages of δ phase in Inconel 718 cold rolled to different reductionsand then treated at different temperatures
for different times were measured by X-ray diffraction,and the effect of
cold rolling on the kinetics of δ phase
precipitation was investigated. Therelationship between the mass percentage of δ phase and annealing time follows the Avramiequation. At 960℃, cold rolling has a little effect on the time exponent (n) and the rate constantof δ phase (α). Below 910 ℃, as cold rolling reduction and annealing temperature increases, theValue of n decreases, whereas the value of or increases. The relationship between the rate constantof δ phase and temperature follows Arrhenius equation. As cold roiling reduction increases,the apparent activation energy of δ precipitation decreases. Cold rolling promotes the γ" → δtransformation. According to the kinetics of δ precipitation, the precipitation-temperature-time(PTT) curves of δphase were given.It has been found that the C curve shifts left as cold rolling reduction increases.