Effects of Reduction-Oxidation Cycles on the Structure, Heat and Corrosion Resistance of Haynes 282 Nickel Alloy Manufactured by Using Powder Bed Fusion-Laser Beam Method

Abstract

The study investigated the effect of the oxidation–reduction cycles on the structure and corrosion resistance of the Haynes 282 nickel superalloy at ambient and elevated temperatures. The comparative studies were performed on specimens produced by the Powder Bed Fusion-Laser Beam (PBF-LB) process and those in the as-received state. The microstructure of the PBF-LB specimens was studied using optical and scanning electron microscopy, whereas the chemical composition of the scale formed after isothermal oxidation in an air atmosphere at 750°C was analysed using energy-dispersive X-ray spectroscopy and X-ray Photoelectron Spectroscopy. The phase composition of the formed scale was determined by X-ray diffraction. Laboratory-induced hydrogen atmosphere was adopted through cathodic charging. A comparison of corrosion resistance was carried out on two types of Haynes 282 specimens, before and after the oxidation and cathodic charging processes. It was found that PBF-LB process could be effectively used to manufacture Haynes 282 nickel superalloy with low porosity and a fine crystalline microstructure. The low-porous, fine-crystalline microstructure of the tested specimens produced by the PBF-LB technique exhibited good resistance to electrochemical corrosion, slightly lower than wrought Haynes 282 nickel superalloy specimens.