Mechanical Degradation by Hot Corrosion of Ni‐Based Superalloy

ABSTRACT The study explores the mechanical degradation by hot corrosion of nickel‐based single‐crystal superalloys in a 900°C Na 2 SO 4 environment via a salt‐coating tensile test. Corrosion forms brittle layers (oxide and sulphide), reducing the effective load‐bearing area. In the sulfide layer, Al depletion causes γ′ phase exhaustion, lowering hardness. The oxide layer, a brittle product, offers no strength. Brittle corrosion products become crack initiation sites, reducing the corroded specimen's elongation and ultimate tensile strength (UTS). The results reveal the effect of hot salt corrosion on the mechanical degradation of the material and provide a theoretical basis for optimizing the corrosion resistance of nickel‐based superalloys.