Insight into surface microstructure evolution and fracture mechanism of incoloy alloy 800HT under high-temperature conditions

High-temperature alloys like Incoloy 800HT are widely used in industries such as power generation and chemical processing, where materials must withstand extreme temperatures, mechanical stress, and corrosive environments. This study investigates how microstructural stability and surface product evolution affect the high-temperature performance of Incoloy 800HT alloys. Aging Material A at 875 °C enhances mechanical stability and oxidation resistance by promoting TiN and Al 2 O 3 formation along grain boundaries. In contrast, Material B shows increased cracking susceptibility due to less TiN, Al 2 O 3 , and M 23 C 6 precipitates. These findings underscore the impact of precipitate distribution on durability under high-temperature stress. In-situ testing further reveals how grain boundary precipitates influence stress distribution and crack behavior, offering insights for designing alloys with improved corrosion resistance and stability in harsh environments.