The high temperature wetting and corrosion mechanism analysis of Nb by TiAl alloy melt

Highlights: • The connection between the high temperature corrosion behavior and GBW process is intuitively established for the first time. • The dynamic angle θ_d evolution is analyzed and the relevant reasons are given to explain the increasement of θ_d. The intermetallic compound layers are corroded with a decreasing rate. • Thermal grooving theory is employed to quantitatively analyzed corrosion profile change with wetting dynamics angle θ_d for the first time. • IMC layers paly a negative role in wetting and erosion. High temperature corrosion behavior of Nb containing a TiAl melt is studied connecting with grain boundary wetting (GBW). Three intermetallic compounds (IMC) layers are formed and corroded step by step via the TiAl melt. The interfacial morphology and wetting angle evolution are investigated theoretically and experimentally. The morphology of the grooves controlled by interfacial tension, while nonzero wetting angles θ_d controlled by surface diffusion are established at the roots. By quantitative assessment, when θ_d is more than 140°, the grooves terminating on a thin sheet, which is responsible for the effective inhibition of further wetting and corrosion.