Enhancing mechanical properties and corrosion resistance of Fe–Cr–B–Mo alloy via the 'Divide and Conquer' strategy for Ti regulation

Abstract

The corrosion of molten aluminium on components in the aluminium industry poses a significant bottleneck, hindering the development of aluminium products and equipment. This study focused on the Fe–Cr–B–Mo alloy, addressing challenges related to the susceptibility of the matrix to corrosion, the excessive brittleness of MB borides (M = Fe, Cr, etc.), and the detachment of corrosion products. A comprehensive study was performed to study the microstructure evolution, mechanical properties, and corrosion behavior of Fe–Cr–B–Mo alloy, considering the 'Divide and Conquer' strategy for Ti regulation. The findings indicate that the heterogeneous nucleation, induced by in situ TiB particles, significantly impacts the refinement of MB borides size and enhances the matrix strength. Notably, the addition of 4.5 wt. % Ti to the T3 alloy significantly enhances its mechanical properties and corrosion resistance. The T3 alloy exhibits an impact toughness of 32.4 kJ/m and a compressive fracture strain of 19.5 %, representing a considerable increase of 58 % and 167 % over the Ti-free alloy, respectively. Furthermore, the alloy has a volume loss rate of 11.0 mm cm h, which is substantially lower, by 73.5 % compared to H13 steel and by 21.4 % compared to the Ti-free alloy. The synergistic presence of TiB and MB borides, along with their corrosion products, functions as an effective diffusion barrier against molten aluminium corrosion.