?precipitate morphology and its dissolution/precipitation kinetics in a special oxiddispersion-strengthened Ni-base superalloy have been investigated. Using an advanced computer programmebased on regression analysis, ...?precipitate morphology and its dissolution/precipitation kinetics in a special oxiddispersion-strengthened Ni-base superalloy have been investigated. Using an advanced computer programmebased on regression analysis, the volume fraction of γ'and its composition as a function of temperaturewere calculated. The lattice constants of both γ'precipitates nd γ matrix have been compared and theresultant lauice misfit computed. Finally, the concentration of AI remaining in γ matrix was determined.The results show generally good agreements with available data for ordinary superalloys. Cornparison ismade against experimental study by using differential scanning calorimetry.展开更多
The microstructure and reerystallisation behaviour of a mechanically alloyed oxide dispersion strength-ened Ni-base superalloy MA758 (Ni30%Cr-0.3 %Al-0.5%Ti-0.6%Y_2O_3(wt%)) have been investigated by us-ing a combinat...The microstructure and reerystallisation behaviour of a mechanically alloyed oxide dispersion strength-ened Ni-base superalloy MA758 (Ni30%Cr-0.3 %Al-0.5%Ti-0.6%Y_2O_3(wt%)) have been investigated by us-ing a combination of analytical techniques including optical metallography. transmission electron microscopyand differential scanning calorimetry. It has been found that the as-extruded bar has a primary recrystallisedstructure, with a grain mean linear intercept of 0.40 μm. Reerystaliisation into a coarse, columnar grain struc-ture takes place at temperature well over 1200℃ . very close to the melting start point of the alloy. The storedenergy responsible for recrystallisation is 0.31 J /g The room temperature Vickers hardness of the alloy dropsfrom 405 for the as-extruded structure to 215 after reerystallisation.展开更多
文摘?precipitate morphology and its dissolution/precipitation kinetics in a special oxiddispersion-strengthened Ni-base superalloy have been investigated. Using an advanced computer programmebased on regression analysis, the volume fraction of γ'and its composition as a function of temperaturewere calculated. The lattice constants of both γ'precipitates nd γ matrix have been compared and theresultant lauice misfit computed. Finally, the concentration of AI remaining in γ matrix was determined.The results show generally good agreements with available data for ordinary superalloys. Cornparison ismade against experimental study by using differential scanning calorimetry.
文摘The microstructure and reerystallisation behaviour of a mechanically alloyed oxide dispersion strength-ened Ni-base superalloy MA758 (Ni30%Cr-0.3 %Al-0.5%Ti-0.6%Y_2O_3(wt%)) have been investigated by us-ing a combination of analytical techniques including optical metallography. transmission electron microscopyand differential scanning calorimetry. It has been found that the as-extruded bar has a primary recrystallisedstructure, with a grain mean linear intercept of 0.40 μm. Reerystaliisation into a coarse, columnar grain struc-ture takes place at temperature well over 1200℃ . very close to the melting start point of the alloy. The storedenergy responsible for recrystallisation is 0.31 J /g The room temperature Vickers hardness of the alloy dropsfrom 405 for the as-extruded structure to 215 after reerystallisation.
