Fracture Behaviors of Oxide Scales on the Metallic Substrate and the Influence of Oxide Scales for the Strength of materials

산화피막의 파괴거동 및 산화피막이 소지금속의 기계적 강도에 미치는 영향

An Fe-25Cr steel was oxidized in Ar at 973K with or without external stesses of 30~35Mpa. A 0.1 ${\mu}{\textrm}{m}$ thick Cr$_2$O$_3$scales was formed during pre-treatment in Ar. Cracking on the oxides scales commenced at the alloy grain boundary by the end of second creep stage, arrayed almost perpendicular to the direction of the tensile directions. On the contrary, a scale formed in $N_2$-0.1%SO$_2$shows poor adherence on the metal substrate. In this case, the strength of materials is much lower than in Ar