Effects of Ultrasonic Nanocrystal Surface Modification on Mechanical and Corrosion Behavior of LZ91 Mg–Li Alloy

抄録

The effects of ultrasonic nanocrystal surface modification (UNSM) treatments on the microstructure, mechanical, and corrosion behavior of LZ91 Magnesium–Lithium (Mg–Li) alloy were systematically investigated. The results show that UNSM treatments have greatly positive effects on the mechanical and corrosion behavior improvements. As compared to the bare sample (BS), the near-surface grains were refined and the surface roughness (R_a) of the sample was reduced from 0.514 µm to 0.082 µm; and the maximum hardness and tensile yield strength remarkable increased by 70% and 65.4% after UNSM treatments, respectively. In addition, the corrosion behavior of LZ91 Mg–Li alloy was also improved after UNSM treatments. The mechanical and corrosion behavior improvements can be attributed to the introduced thick hardening layer with low roughness and smaller grains by UNSM treatments.

UNSM treatment diagram and engineering stress-strain curve of LZ91 Mg–Li alloy 1. A hardening layer was successfully induced on the LZ91 Mg–Li alloy by UNSM treatments. 2. The excellent surface roughness (R_a) was obtained after UNSM treatments. 3. Significant enhancement in hardness and strength was observed after UNSM treatments. 4. The corrosion resistance of the LZ91 Mg–Li alloy was improved after UNSM treatments.