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
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.
