The control of grain size in superalloys is critical in the manufacture of gas turbine blades.The aim of the present research is to provide the technology for producing complicated hollow turbine blades with fine surf...The control of grain size in superalloys is critical in the manufacture of gas turbine blades.The aim of the present research is to provide the technology for producing complicated hollow turbine blades with fine surface grains and better comprehensive mechanical properties.By melt superheating treatment and coating the internal surfaces of shell mould using a cobalt aluminate-bearing coating material,the in-uence of cobalt aluminate as inoculant on the surface grain sizes of turbine blade was studied with addition of cobalt aluminate:0,35%,45%-65% and 100% respectively.At the same time,the effects of cooling circumstances of the blades on surface grain sizes were also experimented under the same addition of cobalt aluminate.The results showed that the melt superheating treatment plays a significant role in the grain size and carbide morphology;and fine surface grains were obtained when the internal surfaces of shell mould were coated using cobalt aluminate coatings.When the addition of cobalt aluminate in coating is between 45%-65%,and the melt is poured into preheated shell moulds with fine silica sand as backing sand,the blades satisfied the surface grain size requirement is over 90%.In addition,comparisons of the surface grain size and the mechanical properties were also conducted between home-made and foreign-made blades.展开更多
A kind of Ni-Cr-Fe-B-Si system amorphous alloy was used as interlayer in transient liquid-phase bonding(TLP bonding)of polycrystalline superalloy K465.The bonding behavior,microstructure feature and the tensile proper...A kind of Ni-Cr-Fe-B-Si system amorphous alloy was used as interlayer in transient liquid-phase bonding(TLP bonding)of polycrystalline superalloy K465.The bonding behavior,microstructure feature and the tensile properties of the joints were investigated.There are B-rich phase and Si-rich phase formed in the center of the seam after bonding at 1210℃for 30 min.The isothermal solidification is complete after bonding at 1210℃for 4 h.The relationship of the average width of the remnant eutectic zone and bonding time at 1210℃is nonlinear.The tensile strength of the bonded joint at room temperature and 900℃is comparable to that of K465 alloy.展开更多
文摘The control of grain size in superalloys is critical in the manufacture of gas turbine blades.The aim of the present research is to provide the technology for producing complicated hollow turbine blades with fine surface grains and better comprehensive mechanical properties.By melt superheating treatment and coating the internal surfaces of shell mould using a cobalt aluminate-bearing coating material,the in-uence of cobalt aluminate as inoculant on the surface grain sizes of turbine blade was studied with addition of cobalt aluminate:0,35%,45%-65% and 100% respectively.At the same time,the effects of cooling circumstances of the blades on surface grain sizes were also experimented under the same addition of cobalt aluminate.The results showed that the melt superheating treatment plays a significant role in the grain size and carbide morphology;and fine surface grains were obtained when the internal surfaces of shell mould were coated using cobalt aluminate coatings.When the addition of cobalt aluminate in coating is between 45%-65%,and the melt is poured into preheated shell moulds with fine silica sand as backing sand,the blades satisfied the surface grain size requirement is over 90%.In addition,comparisons of the surface grain size and the mechanical properties were also conducted between home-made and foreign-made blades.
基金financially supported by the National Basic Research Program China(Nos.2010CB631200 and 2010CB631206)the National Natural Science Foundation of China(Nos.50971124,50904059,51071165,U1037601 and 51204156)
文摘A kind of Ni-Cr-Fe-B-Si system amorphous alloy was used as interlayer in transient liquid-phase bonding(TLP bonding)of polycrystalline superalloy K465.The bonding behavior,microstructure feature and the tensile properties of the joints were investigated.There are B-rich phase and Si-rich phase formed in the center of the seam after bonding at 1210℃for 30 min.The isothermal solidification is complete after bonding at 1210℃for 4 h.The relationship of the average width of the remnant eutectic zone and bonding time at 1210℃is nonlinear.The tensile strength of the bonded joint at room temperature and 900℃is comparable to that of K465 alloy.
