Effect of Nano-Sized γ′ Phase on the Ultrasonic and Mechanical Properties of Ni-Based Superalloy

The effect of the nano-sized γ′ phase on the ultrasonic and mechanical properties of the IN939 superalloy was investigated. The results indicate that the microstructure characteristics of the nano-sized γ′ phase directly affected the ultrasonic longitudinal velocity, the attenuation coefficient, and the mechanical properties. The ultrasonic longitudinal velocity increased with the volume fraction of the γ′ phase, whereas the attenuation coefficient was similar to the fractional change in the γ channel width. The lower fractional change in the γ channel width, in combination with a high volume fraction of the γ′ phase, was conducive to improving the mechanical properties of the superalloy. Additionally, the variation in the ultrasonic properties could reflect the variation in the mechanical properties of the IN939 superalloy, which was beneficial for optimizing the heat treatment process and characterizing the γ′ phase precipitation behavior in a nondestructive manner.