Effect of Y Addition on the Structural Properties and Oxidation Behavior of Fe60Al40-nYn Alloys (n=1, 3, and 5 at.%)

The influence of Y addition on the microstructural features, phase relationships, hardness, magnetic behaviour and cyclic oxidation performance of Fe60Al40-nYn alloys (n = 1, 3, and 5 at.%) has been examined in detail. Al8Fe4Y phase formed even at 1 at.% Y addition because of the limited solid solubility of Y in the FeAl-based phase. For all the examined compositions, the Al8Fe4Y phase developed a eutectic with the FeAl-based phase and its volume fraction increased with increasing Y up to 5 at.%, which is near the eutectic composition. The mean microhardness values increased with increasing Y content for both as-cast and heat-treated samples. Cyclic oxidation tests revealed that the oxidation rate and scale thickness increased with increasing Y content. alpha-Al2O3 was the main surface oxide for all compositions. theta-Al2O3 was also formed with relatively low amount. An internal oxidation layer composed of mixed Al/Y oxides was observed beneath the surface layer.

Automated summary

This study examines the influence of yttrium (Y) addition on the microstructural features, phase relationships, hardness, magnetic behavior, and cyclic oxidation performance of Fe60Al40-nYn alloys. The results show that the addition of Y increases the volume fraction of the Al8Fe4Y phase and improves the hardness of the alloy. Cyclic oxidation tests reveal that increasing Y content accelerates the oxidation rate.