Zheng Li

(TiZrNbMoTa)B _x C high‐entropy alloys coatings have been fabricated by magnetron sputtering and the effects of B content on microstructure, mechanical properties, and corrosion behavior have been systematically investigated. The results indicate that the coatings exhibit a single‐phase face‐centered cubic structure. The addition of B forms reinforcing solid‐solution borides, thus strengthening and hardening the coating. When the B target power is 100 W, the coating hardness can reach 31.22 GPa, the elasticity modulus is 345.82 GPa, and the wear rate reached 9.82 × 10 ⁻⁵ mm ³ /(N·m). As the B target power rises 200 W, the corrosion current density of the (TiZrNbMoTa)B _x C coating in 3.5% NaCl solution decreased from the initial 4.06 × 10 ⁻⁶ to 5.26 × 10 ⁻⁷ A/cm ² . This was mainly attributed to the addition of B, which enhanced the repair of the passivation film of (Borides) and effectively slowed down the corrosion process. This work is about the effect of B doping on the mechanical and corrosion resistance of (TiZrNbMoTa)B _x C coatings, providing theoretical support for improving the surface wear and corrosion resistance of engineering materials.

The fir-tree blade tenon is an important connection part of the turbine blade; its machining quality directly affects the life and power of the aeroengine. At present, the machining of the blade tenon requires multiple profile grinding processes. This study highlights the whole profile of the grinding processes of K4002 nickel-based superalloy blade tenons in ultrasonic vibration-assisted grinding (UVG). A probability superposition method was utilized to calculate the undeformed chip thickness and contact rate considering the random distribution of the abrasive grains and the overlap of the grinding trajectories. Subsequently, the grinding force, grinding temperature and surface integrity of the blade tenons in conventional grinding (CG) and UVG were investigated. The results indicate that the ultrasonic vibration causes intermittent cutting behavior which can reduce the contact rate to 0.6 at most. The grinding force, grinding temperature and surface integrity are deeply affected by the fir-tree shape of the blade tenon. The maximum grinding force occurs at the start of the full contact stage; surface burnout easily occurs in the middle top area of the blade tenon. Compared to CG, the use of UVG leads to an average reduction in the grinding force and temperature by 20% and 23%, respectively, improving the surface burnout of the K4002 superalloy.

The binary nitride coatings corresponding to Ti, Zr, Nb, Mo, and Ta have good thermal stability, hardening wear resistance, and high-temperature oxidation resistance. Therefore, the high-entropy alloy nitride coating composed of these five elements is expected to show excellent mechanical properties, and it is suitable for extending tool life in dry-cutting environments. In this paper, (TiZrNbMoTa)Nx high-entropy nitride films were synthesized using a multitarget nonequilibrium magnetron sputtering technique. The paper aimed at investigating the effects of different nitrogen flow rates (FN) on the microstructure and mechanical properties of the films. The results show that, with the increase in FN, the deposition rate gradually decreased, the films exhibited a face-centered cubic structure, and the grain gradually changed from coarse columnar crystals to ultrafine grain structures. The hardness, elastic modulus, and binding force all showed a tendency to increase and then decreased with increasing FN. The hardness and elastic modulus reached their maximum values of 34.39 and 400.97 GPa, respectively, at an FN of 60 SCCM, and the formation of covalent bonds and grain refinement promoted the increase in hardness. This research provided a theoretical foundation for designing and preparing high-entropy ceramic coatings with high performance.