The corrosion behaviors of 91W-6Ni-3Fe （91W） refractory alloy, TiAl intermetallic compound and two types of iron based alloys （QT700 and H13 tool steel） in a liquid aluminum were investigated. Corrosion experiments or static immersion-tests were carried out in pure molten aluminum at 750 ℃. The surface micro-topographies, corrosion interfaces and phase compositions of the immersed samples were investigated by 3D optical microscopy, SEM, EDS and XRD. The results show that 91W exhibits the best corrosion resistance, followed by QT700, H13 and TiAl alloy, consequently. The corrosion mass loss of the four metallic materials adheres to parabolic criterion, and the corrosion rate trends to be stable after initial acceleration. The diffusion-reaction mechanism is proposed for the dissolution of materials in molten aluminum, and the diffusion process is the rate-determining step during the dissolution of 91W in molten aluminum, while the low activation energy for the reaction between TiAl-（TiAl3）-Al couple results in poor corrosion resistance of TiAl alloy in molten aluminum.
The corrosion behavior of an Fe-20Mn-11Al-1.8C-5Cr alloy prepared by spark plasma sintering was investigated via immersion tests in molten aluminum at 750℃ for 1 and 4 h, respectively, and a hot work steel （AlSI H13） was included as a reference. The experimental results show that the corrosion rate of Fe-20Mn-11Al-1.8C-5Cr alloy is - 24% of that of H13 steel, suggesting that Fe-20Mn-11Al-1.8C-5Cr alloy in molten aluminum possesses better corrosion resistance than H13 steel. Detailed analysis show that k-carbide （（Fe, Mn）3AlCx） and Cr7C3 carbide precipitated in the matrix play a key role in enhancing the corrosion resistance of Fe-20Mn-11Al-1.8C-5Cr alloy in molten aluminum. Both of them show better corrosion resistance than 7-Fe matrix and H13 steel, and can also take on the role of roots in grasping the corrosion product and restrain them from spalling into the molten aluminum.
