Hastelloy X is a high-temperature nickel-based alloy used in hot end components such as combustion chambers of aero-engines.
The combustion chamber is subjected to high temperature oxidation and corrosion during service, which accelerates its failure. In order to extend the service life of the combustion chamber, surface modification technology is used to treat the combustion chamber material to improve its surface properties.
High Current Pulsed Electron Beam (HCPEB) was used to modify the surface of Hastelloy X (the number of treatments was 1, 5, 10, and 20 times, respectively), and the surface microstructure and surface properties of HCPEB-modified Hastelloy X were investigated through the micro-morphological observation, high-temperature oxidization, thermal corrosion, and electrochemical corrosion tests of the alloy before and after modification. surface microstructure and surface properties after HCPEB modification.
HCPEB bombardment melts the metal surface, the distribution of alloying elements is homogenized, the solid solubility of the elements is increased, the typical crater morphology appears, and the surface grain refinement; after the bombardment is finished, the surface of the specimen is rapidly cooled and solidified to show a corrugated wrinkle morphology, and the remelted layer and heat-affected zone are formed from the outside to the inside of the material, and the surface undergoes plastic deformation, and the deformation structure such as slip bands appears. With the increase of the number of HCPEB treatments, the density of craters on the surface of the alloy decreases, the size becomes larger, and the range of remelted layer and heat-affected zone increases.
The results of high-temperature oxidation experiments showed that the high-temperature oxidation resistance of Hastelloy X was significantly improved after HCPEB treatment, with the best high-temperature resistance of the sample after 5 bombardments. The results of thermal corrosion experiments showed that the thermal corrosion resistance of the samples was gradually improved with the increase of the number of HCPEB bombardment. The results of electrochemical experiments show that HCPEB bombardment improves the electrochemical corrosion resistance of Hastelloy X, and the sample has the best corrosion resistance after 1 bombardment.
This paper explains the reasons for the improvement of surface chemical properties of Hastelloy X by HCPEB bombardment through microscopic characterization: the electron beam bombardment caused the surface remelting, the surface organization became denser, the grain refinement, the solid solubility increased, and the surface elemental distribution was more uniform, and the effect of grain refinement contributed to the enhancement of the resistance to oxidation at high temperatures, and the increase of elemental solid solubility improved the heat and corrosion resistance, and the homogenization of the surface organization contributed to the enhancement of the electrochemical corrosion resistance. Electrochemical corrosion resistance is improved by the homogenization of the surface composition.
Post time: Aug-05-2023
