Strain induced precipitation of gamma '' phase and the gamma ''->delta transformation in Inconel 718

The effects of strain on the precipitation of gamma " phase and the --> del ta tranasformation have been investigated. At 810 degrees C, the gamma " pr ecipitation precedes the delta precipitation, and the gamma " precipitation has just reached the saturation level before the y " --> delta transformat ion occurs. Strain induces both the precipitation of gamma " phase and the gamma " --> delta transformation. The relationship between the amount of de lta phase and aging time follows the Avrami equation. As cold rolling reduc tion increases, the time exponent (n(1)) decreases, while the rate of the d elta precipitation increases. The kinetics of the gamma " --> delta transfo rmation can also be described by the Avrami equation.