Study On Corrosion Resistance Of Pre-Oxidized Al_xCoCrFeNi High-Entropy Alloy In Aluminum Molten

In industrial production,aluminum and aluminum melts are usually involved.Aluminum molten is one of the most corrosive materials,causing severe corrosion to the alloy and the overall material,resulting in failure of the overall material.Improving the corrosion resistance of the materials in metal molten is of great significance for extending the service life of the equipment,improving the production efficiency and the quality of the aluminum products and the aluminized parts in the present work.As a unique multi-principal alloy,high-entropy alloy has attracted the attention of researchers because of its outstanding mechanical properties and good high-temperature stability.The most important thing about high-entropy alloys is the four effects of high-entropy alloys:high entropy effect,sluggish diffusion effect,severe lattice-distortion effect,and cocktail effect.At present,the research about the corrosion resistance of high-entropy alloy in metal molten is still in its infancy.The sluggish diffusion effect of high-entropy alloy in aluminum molten has not been systematically studied.This study intends to utilize sluggish diffusion effect of high-entropy alloys and pre-oxidized the surface of the alloy.As a double diffusion barrier layer in the corrosion of aluminum molten,the high-entropy alloy overall material with the best corrosion resistance of aluminum molten is designed,to improve the corrosion resistance of existing overall alloy materials to aluminum molten.In the present study,the effect of the content of Al on the crystal structure,microstructure and the corrosion resistance of Al_xCoCrFeNi high-entropy alloys was studied.The results show that,with the increase of the content of Al,the crystal structure of high-entropy alloy changes from FCC to BCC,more dendritic tissue appears in the microstructure and the dendritic tissue is finer.The aluminum molten corrosion resistance of high entropy alloy increases with the increase of Al content in the alloy,the aluminum molten corrosion resistance is better than most common alloy in industrial production like pure iron and 316L stainless steel.Then,the effect of the content of elements in the alloy and preoxidation process on the type and the density of oxides.By changing the Al content and pre-oxidation temperature of Al_xCoCrFeNi high-entropy alloy,it is found that the Al_0.5CoCrFeNi high-entropy alloy oxide film pre-oxidized at 1000?is the most dense,and the surface mainly produces the oxides like Cr₂O₃ with excellent corrosion resistance to aluminum.Finally,the effect of pre-oxidation on the corrosion resistance of Al_0.5CoCrFeNi high-entropy alloy in aluminum molten was analyzed.The corrosion resistance in aluminum molten of Al_0.5CoCrFeNi high-entropy alloy is significantly improved by pre-oxidation treatment.The corrosion rate of pre-oxidized Al_0.5CoCrFeNi high-entropy alloy in aluminum molten decreased from 0.85×10^-1mm/h to 2.30×10^-3mm/h compare to as-cast Al_0.5CoCrFeNi high-entropy alloy,the aluminum resistant in aluminum molten is increased by40 times,compared with the most common alloys like pure iron and 316L stainless steel in traditional industrial production,the corrosion resistance in aluminum molten is improved by about 150 times.Among them,the corrosion resistance in aluminum molten of Al_0.5CoCrFeNi high-entropy alloy after 1000? pre-oxidation treatment is the best.