Effect of surface boroaluminizing on thermal corrosion behavior of TC4 (Ti-6AL-4V) titanium alloy

Abstract

In this experiment, boronizing and boroaluminizing are respectively carried out on the surface of TC4 titanium alloy to improve the thermal corrosion resistance of the titanium alloy surface. The microstructure of the infiltration layer was observed by SEM, and the phase of the infiltration layer before and after thermal corrosion was determined by EDS analysis and XRD test. The change of element content was determined by SEM line scanning. The samples were subjected to thermal corrosion experiments respectively, and the thermal corrosion kinetics curves were drawn according to the experimental results. The results show that the infiltration layer formed by boroaluminizing on TC4 titanium alloy surface is relatively compact, and the particle size distribution on the infiltration layer is smaller. The hardness achieved by surface boroaluminizing is 1221 HV, and the brittleness is reduced. The corrosion weight gain is 0.281 25 mg cm−2 and 0.029 41 mg cm−2 at 700 °C and 900 °C, respectively. Compared with TC4 alloy substrate and boronizing sample, the corrosion weight gain is greatly reduced, and the resistance to thermal corrosion is greatly enhanced.