High-temperature oxidation behaviour and influence on the fracture property of compacted graphite iron

High-temperature oxidation and uniaxial tensile tests were conducted on cylinder head cast iron material to investigate oxidation kinetics, surface and cross-section oxidation features, oxidation growth behaviour, and the influence of oxidation on fracture through characterisation analysis of microstructure. The results indicate that the oxidation kinetics approximately follow the parabolic rate law above 570℃ but exhibit poor consistency at 500℃. A multi-layered oxide structure forms with unique morphological characteristics in a cross-sectional direction. Based on the spatial distribution of graphite, two oxidation mechanisms were identified in both the matrix and graphite phases. Uniaxial tensile tests reveal that the mechanical and fracture properties of the material are significantly affected by the oxidation temperature.