INCO-617 alloy hollow sphere foams with average aperture of about 3 mm and about 0.12 mm wall thickness were fabricated by hollow sphere method.Firstly the wet spheres,which are formed as powder shells from slurry by ...INCO-617 alloy hollow sphere foams with average aperture of about 3 mm and about 0.12 mm wall thickness were fabricated by hollow sphere method.Firstly the wet spheres,which are formed as powder shells from slurry by coating polystyrene balls,were arranged with body-centered cubic(BCC) structure.Subsequently,the sphere stacks were heat-treated in vacuum at 350 ℃ for 40 min to decompose the organic materials,and sintered at different temperatures for different time.The effects of slurry components,sintering temperature and sintering time on the density and porosity of cell wall of hollow sphere foam were studied through Scanning Electron Microscopy.The results show that the densities of INCO-617 alloy hollow sphere foam,increasing with the increase of powder content in slurry,sintering temperature and sintering time,range from 1.112 to 1.216 g·cm-3.Extension of sintering time can reduce the porosity of cell wall,which enhances the compression strength of hollow sphere foam significantly.展开更多
The microstructure and mechanical properties of alloy 617 B in the process of 5000 h aging at 750 °C were systematically investigated by means of SEM, TEM and mechanical analysis. M23C6 particles were dispersed i...The microstructure and mechanical properties of alloy 617 B in the process of 5000 h aging at 750 °C were systematically investigated by means of SEM, TEM and mechanical analysis. M23C6 particles were dispersed inside grains and distributed discontinuously along grain boundaries and γ′ phases were situated at intragranular sites in the process of aging. The size of precipitates increased with increasing aging time. Inter- and intra-granular carbide and γ′ phase particles inside grains resulted in the precipitation strengthening of this aged alloy, enhancing the strength and hardness. The aged alloy possessed good stabilities of hardness and strength during aging. An obvious decrease of the toughness of this aged alloy was due to γ′ phase particles limiting plastic deformation to the area nearby grain boundaries, resulting in the occurrence of crack along grain boundaries. Additionally, the intergranular cracks apparently led to a decrease in the toughness for this aged alloy due to carbide particles at grain boundaries. The toughness of this aged alloy was fairly stable possibly due to the unchanged distribution of the precipitates during aging.展开更多
文摘INCO-617 alloy hollow sphere foams with average aperture of about 3 mm and about 0.12 mm wall thickness were fabricated by hollow sphere method.Firstly the wet spheres,which are formed as powder shells from slurry by coating polystyrene balls,were arranged with body-centered cubic(BCC) structure.Subsequently,the sphere stacks were heat-treated in vacuum at 350 ℃ for 40 min to decompose the organic materials,and sintered at different temperatures for different time.The effects of slurry components,sintering temperature and sintering time on the density and porosity of cell wall of hollow sphere foam were studied through Scanning Electron Microscopy.The results show that the densities of INCO-617 alloy hollow sphere foam,increasing with the increase of powder content in slurry,sintering temperature and sintering time,range from 1.112 to 1.216 g·cm-3.Extension of sintering time can reduce the porosity of cell wall,which enhances the compression strength of hollow sphere foam significantly.
基金Project(2012AA050501)supported by the National High-tech Research and Development Program of ChinaProject(NY20110102)supported by the National Energy Applied Technology and Engineering Demonstration Program,China+1 种基金Project(2012CB724401)supported by the National Basic Research Program of ChinaProject(003)supported by CSEE Youth Science & Technology Innovation,China
文摘The microstructure and mechanical properties of alloy 617 B in the process of 5000 h aging at 750 °C were systematically investigated by means of SEM, TEM and mechanical analysis. M23C6 particles were dispersed inside grains and distributed discontinuously along grain boundaries and γ′ phases were situated at intragranular sites in the process of aging. The size of precipitates increased with increasing aging time. Inter- and intra-granular carbide and γ′ phase particles inside grains resulted in the precipitation strengthening of this aged alloy, enhancing the strength and hardness. The aged alloy possessed good stabilities of hardness and strength during aging. An obvious decrease of the toughness of this aged alloy was due to γ′ phase particles limiting plastic deformation to the area nearby grain boundaries, resulting in the occurrence of crack along grain boundaries. Additionally, the intergranular cracks apparently led to a decrease in the toughness for this aged alloy due to carbide particles at grain boundaries. The toughness of this aged alloy was fairly stable possibly due to the unchanged distribution of the precipitates during aging.
