475 °C embrittlement

475 °C embrittlement refers to a phenomenon observed in certain types of ferritic stainless steels and other iron-based alloys, where prolonged exposure to temperatures around 475 °C (about 885 °F) leads to a reduction in ductility and toughness. This embrittlement is primarily attributed to the precipitation of an iron-rich phase known as "sigma phase" or the formation of non-uniform compositions in the microstructure, which can lead to the loss of the material's structural integrity.