Surface morphology and integrity research of ultrasonic-assisted milling of cast superalloy K4169

The nickel-based casting superalloy K4169 is extensively utilized in aerospace engines for its extraordinary mechanical and thermal properties. However, achieving high surface integrity of the superalloy remains challenging. Ultrasonic-assisted machining (UAM) is an advantageous technology, while the influence on cast superalloy is imperative to be revealed. The study on surface morphology and integrity of K4169 was carried out using ultrasonic-assisted end milling. The results showed that the ultrasonic vibration effectively suppresses surface defects and facilitates a regular surface texture. A more significant deformed layer of 7.3 μm was induced in UAM, representing a 97% enhancement relative to CM. Additionally, surface microhardness and compressive residual stress show a tendency to increase with ultrasonic amplitude. Specifically, the surface compressive residual stress in UAM reached 822 MPa, signifying a 69.6% increase over CM.