In cooling process of Fe-Cr-Al alloy oxidized at 1 300 ℃, the effect of cooling speed and exposure time on oxide spalled area fraction and successive variety of the spalled region were studied by investigating evolve...In cooling process of Fe-Cr-Al alloy oxidized at 1 300 ℃, the effect of cooling speed and exposure time on oxide spalled area fraction and successive variety of the spalled region were studied by investigating evolvement of the thermally grown oxide using in-situ CCD monitoring technique. The results showed that oxide spallation can be restrained by controlling cooling speed and the critical temperature drop of spallation initiation which is closely related to the oxide thickness or exposure time, and the spallation process of a little region may be described in more detail as two routes： from the oxide/substrate interface micro-decohesion, micro-buckles, buckle spreading, buckle crack to spallation and from the interface micro-decohesion, micro-buckles, buckle crack and spallation to the residual oxide decohesion and spallation.展开更多
In Fe-20Cr-4Al-0.5Si-(0.13-0.73)Y alloys,a new phase consisting of 15.8 wt-% Y,65.4 wt-% Fe,12.6 wt-% Cr,4.4 wt-% Al and 1.4 wt-% Si was observed with its Y-content and crys- tal structure being identical with those o...In Fe-20Cr-4Al-0.5Si-(0.13-0.73)Y alloys,a new phase consisting of 15.8 wt-% Y,65.4 wt-% Fe,12.6 wt-% Cr,4.4 wt-% Al and 1.4 wt-% Si was observed with its Y-content and crys- tal structure being identical with those of YFe_9 phase basically and the microhardness being 4-5 times higher than that of α-phase matrix.It is a kind of stable particles (2-10 μm) dispersed over the matrix. For Y-free or less alloy,the plasticity dropped sharply after high temperature treatment,while the plasticity is retained for the alloys containing 0.41-0.73 wt-% Y treated below 1340℃,because the Y-containing particles can strongly prevent from grain growth,and dislocation annihilation, and trap impurities.If treatment temperature is higher than 1340℃,however,these actions will dis- appear owing to the melting of the particles.展开更多
基金Item Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars
文摘In cooling process of Fe-Cr-Al alloy oxidized at 1 300 ℃, the effect of cooling speed and exposure time on oxide spalled area fraction and successive variety of the spalled region were studied by investigating evolvement of the thermally grown oxide using in-situ CCD monitoring technique. The results showed that oxide spallation can be restrained by controlling cooling speed and the critical temperature drop of spallation initiation which is closely related to the oxide thickness or exposure time, and the spallation process of a little region may be described in more detail as two routes： from the oxide/substrate interface micro-decohesion, micro-buckles, buckle spreading, buckle crack to spallation and from the interface micro-decohesion, micro-buckles, buckle crack and spallation to the residual oxide decohesion and spallation.
文摘In Fe-20Cr-4Al-0.5Si-(0.13-0.73)Y alloys,a new phase consisting of 15.8 wt-% Y,65.4 wt-% Fe,12.6 wt-% Cr,4.4 wt-% Al and 1.4 wt-% Si was observed with its Y-content and crys- tal structure being identical with those of YFe_9 phase basically and the microhardness being 4-5 times higher than that of α-phase matrix.It is a kind of stable particles (2-10 μm) dispersed over the matrix. For Y-free or less alloy,the plasticity dropped sharply after high temperature treatment,while the plasticity is retained for the alloys containing 0.41-0.73 wt-% Y treated below 1340℃,because the Y-containing particles can strongly prevent from grain growth,and dislocation annihilation, and trap impurities.If treatment temperature is higher than 1340℃,however,these actions will dis- appear owing to the melting of the particles.
