Effect of Carbon Nanotube Content on Microstructure, Mechanical Properties and Oxidation Properties of FeAl Intermetallic Compounds

FeAl-based composites with 0, 0.2, 0.5, 0.8 and 1.1 wt.% CNTs were prepared by high-energy ball milling and hot-pressing sintering. The microstructure, mechanical properties and oxidation resistance of CNTs/FeAl composites were tested and analyzed. The results show that the main phases of CNTs/FeAl bulk composites are FeAl phase with B2 structure, α-Al2O3 and AlFe3C0.5. The microstructure distribution is relatively uniform. With the increase of CNTs content, the hardness and tensile strength of CNTs/FeAl composites first increase and then decrease. When the CNTs content is 0.8 wt.%, the two parameters reach the maximum, 53.2% and 25.8% higher than FeAl, respectively. After adding CNTs, the oxidation resistance of CNTs/FeAl composites is improved, and the oxidation weight gain of CNTs/FeAl composites is one order of magnitude lower than that of FeAl alloy. This is due to the presence of thin and dense oxidation film mainly composed of α-Al2O3 and α-Fe2O3 on the material surface.