Effect of Zr and Ti on Microstructure and Corrosion Resistance in Al-4Ce Alloy

An aluminum-cerium alloy (Al-4wt.%Ce) is a thermal stability high-temperature alloy. The objective of this study was to improve the microstructure and corrosion resistance of an Al-4Ce alloy. Comparison the efficiency of in-situ grain refinement assisted with ultrasonic melt processing was induced by adding the in-situ Al-10Zr- 2.5Ti and Al-10Ti-2B to the molten alloy. The addition of Zr and Ti in Al-4Ce alloy may form Al3Ti and Al3Zr which more effective in grain refinement. Corrosion resistance of Al-4wt.%Ce alloy was investigated by salt spray test and electrolytic corrosion method in 3.5 wt.%NaCl solution. The results showed that the grain structure was refined by adding Zr and Ti up to 0.2 wt.%Zr and 0.02 wt.%Ti. The electrochemical polarization curves proved that the Ecorr increased after adding Zr as compared to the base Al-Ce alloy. Corrosion resistance of the alloy may result from the formation of intermetallic phase.