Effect of ultrasonic nanocrystalline surface modification on hardness and elastic modulus of Ti-6Al-4V alloy

This study examined the effect of ultrasonic nanocrystalline surface modification (UNSM) on the mechanical properties of Ti-6Al-4V titanium alloy. Samples with dimensions of 80 × 10 × 5 mm were treated using varying amplitudes (20–40 μm), static loads (20–60 N), and processing temperatures up to 400 ℃. The primary aim of this research was to identify the optimal processing parameters of UNSM to achieve superior mechanical properties and enhanced performance of the Ti-6Al-4V alloy. Systematic experiments were conducted by varying key parameters, such as ultrasonic amplitude, processing temperature, and applied static loads. The results revealed that the optimal UNSM parameters—30 μm amplitude, 400 ℃ processing temperature, and 40–60 N static load—significantly improved mechanical properties. Hardness increased from 394 (untreated) to 475 HV, while the elastic modulus reached 156 GPa, demonstrating substantial enhancements. Microstructural analysis confirmed that UNSM treatment promotes grain refinement, resulting in improved mechanical characteristics in the surface layer of the alloy. These findings highlight the potential of UNSM technology for applications requiring enhanced surface durability, strength, and wear resistance. This research provides valuable insights for industrial sectors, including aerospace, biomedical, and automotive industries, where high-performance materials are critical.