Statistical manipulation of material data was conducted for probabilistic life assessment or risk-based design and maintenance for high temperature components of power plants. To obtain the statistical distribution of...Statistical manipulation of material data was conducted for probabilistic life assessment or risk-based design and maintenance for high temperature components of power plants. To obtain the statistical distribution of material properties, dominant parameters affecting material properties are introduced into normalization of statistical variables. Those parameters are hardness, chemical composition, characteristic micro structural features and so on. Creep and fatigue properties are expressed by normalized parameters and the unified statistical distributions are obtained. These probability distribution functions show good coincidence statistically with the field database of steam turbine components. It was concluded that the unified statistical baseline approach is useful for the risk management of components in power plants.展开更多
Cyclic oxidation behavior of two-phaseγ+γ'-Ni-22Al-5 and -10 Pt alloys in air with and without 30 vol.%H_2O at 1000℃was investigated.The oxidation of 5 and 10 Pt alloys in air was initially rapid and followed b...Cyclic oxidation behavior of two-phaseγ+γ'-Ni-22Al-5 and -10 Pt alloys in air with and without 30 vol.%H_2O at 1000℃was investigated.The oxidation of 5 and 10 Pt alloys in air was initially rapid and followed by a slow steady-state stage.The oxidation during this steady-state stage was followed the parabolic rate law,and the parabolic rate constants for the two different Pt content alloys were similar.However the mass change of 5 Pt alloy during the initial rapid oxidation stage was much higher than that of 10 Pt,and it resulted in higher oxidation mass gain on 5 Pt alloy after 500 cycles.Similar oxidation behavior,initial rapid followed by slow steady-state,was observed when the alloys were oxidized in air+30%H_2O,however the initial oxidation mass change in the wet atmosphere was much higher for both alloys than in air.Interestingly,the oxidation rate constants for both alloys during the steady-state stage significantly decreased in the atmosphere with water vapor.Particularly,oxidation mass gain on the 5 Pt alloy was not observed after about 100 cycles of oxidation.展开更多
文摘Statistical manipulation of material data was conducted for probabilistic life assessment or risk-based design and maintenance for high temperature components of power plants. To obtain the statistical distribution of material properties, dominant parameters affecting material properties are introduced into normalization of statistical variables. Those parameters are hardness, chemical composition, characteristic micro structural features and so on. Creep and fatigue properties are expressed by normalized parameters and the unified statistical distributions are obtained. These probability distribution functions show good coincidence statistically with the field database of steam turbine components. It was concluded that the unified statistical baseline approach is useful for the risk management of components in power plants.
文摘Cyclic oxidation behavior of two-phaseγ+γ'-Ni-22Al-5 and -10 Pt alloys in air with and without 30 vol.%H_2O at 1000℃was investigated.The oxidation of 5 and 10 Pt alloys in air was initially rapid and followed by a slow steady-state stage.The oxidation during this steady-state stage was followed the parabolic rate law,and the parabolic rate constants for the two different Pt content alloys were similar.However the mass change of 5 Pt alloy during the initial rapid oxidation stage was much higher than that of 10 Pt,and it resulted in higher oxidation mass gain on 5 Pt alloy after 500 cycles.Similar oxidation behavior,initial rapid followed by slow steady-state,was observed when the alloys were oxidized in air+30%H_2O,however the initial oxidation mass change in the wet atmosphere was much higher for both alloys than in air.Interestingly,the oxidation rate constants for both alloys during the steady-state stage significantly decreased in the atmosphere with water vapor.Particularly,oxidation mass gain on the 5 Pt alloy was not observed after about 100 cycles of oxidation.
