Study on the micro-motion wear mechanism of K417 alloy at high temperature under different normal load conditions

Rim plate dry friction dampers have become increasingly popular in recent years as a simple and effective method of friction damping in various types of high-speed rotating machinery blades. This method improves the service life of turbine blades and enhances the safety and reliability of aero-engines by utilizing the friction between the damping material and the blade material to counteract the vibration energy generated. However, under different conditions, frictional wear can cause abnormal wear, material transfer, micro-crack generation, and expansion between the damping block and the blade. These issues may lead to premature failure of the component. This experiment utilized a cylindrical/planar line contact form for the rim-plate dry friction damper and blade contact parameters. Micro-motion wear experiments were conducted at high-temperature conditions in the SRV-V multifunctional friction and wear tester to simulate the contact state of the dry friction damper block and turbine blade under working conditions. The study investigated the micro-motion friction and wear behavior of K417 alloy under varying normal contact stress conditions. The results indicated an inverse relationship between the friction coefficient and the normal load in the same micro-motion environment. Additionally, the degree of fluctuation flattens out with an increase in load. The normal load increase caused the micro-motion operating region characteristics to transition from the complete slip zone to the mixed zone. In the complete slip zone, the micro-motion wear forms were mainly abrasive, fatigue, and oxidative wear, while in the mixed zone, they were mainly adhesive and oxidative wear. Under low load conditions, the bonding degree between the three-body layer and the substrate material was more effective, resulting in better substrate protection. However, under high load conditions, the increase in contact stress caused a decline in the bonding degree between the two, resulting in cracking and crushing of the three-body layer and loss of substrate protection, leading to gradual damage.