Effects of Hot Corrosion on Fatigue Performance of GH4169 Alloy

In this study, GH4169 alloy was hot-corroded using NaCl+Na2SO4 salts; the microstructures, composition and hardness of hot corrosion (HC) layer were investigated, and fatigue tests were conducted on the as-received and hot-corroded GH4169 alloy. The results show that HC causes oxidation and sulfidation in GH4169 alloy. The formed sulfide layer is beneath the oxide layer, and the hardness obtained by nano-indentation analysis follows a sequence of oxide layer > alloy matrix > sulfide layer. HC accelerates fatigue crack initiation and significantly reduces GH4169 alloy fatigue life. It is believed the reduced fatigue life is probably ascribed to spallation of HC layer, stress concentration effects caused by HC pits, plastic deformation in sulfide layer and microcracks in oxide layer.

Automated summary

The study found that GH4169 alloy undergoes oxidation and sulfidation during hot corrosion, forming a sulfide layer beneath the oxide layer. Hot corrosion accelerates fatigue crack initiation and significantly reduces the alloy's fatigue life.