The G3 and 825 alloys,with excellent combination of mechanical properties and corrosion resistance,can be used in hot,and acid environments.Thermal simulation tests were conducted on the alloys G3 and 825 in the THERM...The G3 and 825 alloys,with excellent combination of mechanical properties and corrosion resistance,can be used in hot,and acid environments.Thermal simulation tests were conducted on the alloys G3 and 825 in the THERMECMASTOR-Z simulator,at temperature between 1030 and 1300 ℃,with strain rate from 1 to 50 s-1 and strain ε=0.8.The variations of flow stress with deformation temperature and strain rate were presented.Change of alloy structure with hot deformation and effect of strain rate on alloy dynamic recrystallization have been studied through microstructure observation by OM,SEM and TEM.Moreover,hot plasticity characteristics of alloy were analyzed by temperature-reduction of area curves.The results showed that available hot working temperature for G3,G3-Z and 825 was 1100 to 1240 ℃,1130 to 1220 ℃ and 1050 to 1240 ℃,respectively.The reliable information on hot working in the alloy pilot production in steelwork is given.展开更多
Superalloy Inconel 825 has been extensively used in chemical industry and transportation industry due to its excellent creep rupture strength and prominent corrosion resistant properties under various circumstances.Ho...Superalloy Inconel 825 has been extensively used in chemical industry and transportation industry due to its excellent creep rupture strength and prominent corrosion resistant properties under various circumstances.However,the mass production of this alloy by continuous casting method is restricted because of the serious macrosegregation and coarse grains in the billet.In current,a linear travelling magnetic field was introduced in the solidification process of Inconel 825 with the aim of changing the final microstructure by electromagnetic stirring(EMS)force.The results have indicated that the dendrite structure of Incoloy 825 is refined obviously with applying EMS,and the mechanism of dendrite refinement is presumed to the introduction of a forced convection within the solidifying melt.Moreover,The number and the size of precipitated phases including carbide and nitride were found to be significantly reduced with EMS, a phenomenon on the reduction of interdendritic segregation of titanium and molybdenum was simultaneously observed, which demonstrated that he release of interdendritic segregation by EMS inhibits the growth dynamic of carbide and nitride from the melt.展开更多
Predicting wind turbine S825 airfoil＇s aerodynamic performance is crucial to improving its energy efficiency and reducing its environmental impact. In this paper, a numerical simulation on the wind turbine S825 airfo...Predicting wind turbine S825 airfoil＇s aerodynamic performance is crucial to improving its energy efficiency and reducing its environmental impact. In this paper, a numerical simulation on the wind turbine S825 airfoil is con- ducted with k-to turbulence model at different attack angles. By comparing with experimental data, a new method of modifying k-to model is proposed. A modifying function is proposed to limit the production term in ω equation based on fluid rotation and deformation. This method improves turbulent viscosity and decreases separating re- gion when the airfoil works at large separating conditions. The predictive accuracy could be improved by using the modified k-to turbulence model.展开更多
本文从Controller Area Network(CAN)总线的特点出发,通过将CAN总线与机载领域应用最成熟的1553B总线进行对比,分析了在航空领域,尤其是在航空机电系统中,局部采用CAN总线的可行性。然后从可靠性和实时性两个方面指出了CAN总线需要在机...本文从Controller Area Network(CAN)总线的特点出发,通过将CAN总线与机载领域应用最成熟的1553B总线进行对比,分析了在航空领域,尤其是在航空机电系统中,局部采用CAN总线的可行性。然后从可靠性和实时性两个方面指出了CAN总线需要在机载适应性上进行的改进。最后结合国外已经发布的CANaerospace和ARINC825协议,指出了在高层协议方面改进的要点,并简要介绍了在国外飞机上CANaero-space和ARINC825的应用实例。展开更多
文摘The G3 and 825 alloys,with excellent combination of mechanical properties and corrosion resistance,can be used in hot,and acid environments.Thermal simulation tests were conducted on the alloys G3 and 825 in the THERMECMASTOR-Z simulator,at temperature between 1030 and 1300 ℃,with strain rate from 1 to 50 s-1 and strain ε=0.8.The variations of flow stress with deformation temperature and strain rate were presented.Change of alloy structure with hot deformation and effect of strain rate on alloy dynamic recrystallization have been studied through microstructure observation by OM,SEM and TEM.Moreover,hot plasticity characteristics of alloy were analyzed by temperature-reduction of area curves.The results showed that available hot working temperature for G3,G3-Z and 825 was 1100 to 1240 ℃,1130 to 1220 ℃ and 1050 to 1240 ℃,respectively.The reliable information on hot working in the alloy pilot production in steelwork is given.
基金Item Sponsored by National Natural Science Foundation of China[Nos.50834009 and 51104047]the Doctoral Fund of Ministry of Education of China[No.20100042120001]+2 种基金the Fundamental Research Funds for the Central Universities under Grants[Nos.N090309001 and N090109001]Key Grant Project of China Ministry of Education (No.311014) the 111 Project of China[No.B07015]
文摘Superalloy Inconel 825 has been extensively used in chemical industry and transportation industry due to its excellent creep rupture strength and prominent corrosion resistant properties under various circumstances.However,the mass production of this alloy by continuous casting method is restricted because of the serious macrosegregation and coarse grains in the billet.In current,a linear travelling magnetic field was introduced in the solidification process of Inconel 825 with the aim of changing the final microstructure by electromagnetic stirring(EMS)force.The results have indicated that the dendrite structure of Incoloy 825 is refined obviously with applying EMS,and the mechanism of dendrite refinement is presumed to the introduction of a forced convection within the solidifying melt.Moreover,The number and the size of precipitated phases including carbide and nitride were found to be significantly reduced with EMS, a phenomenon on the reduction of interdendritic segregation of titanium and molybdenum was simultaneously observed, which demonstrated that he release of interdendritic segregation by EMS inhibits the growth dynamic of carbide and nitride from the melt.
基金supported by the National Natural Science Foundation of China(No.51420105008,No.51376001)the National Basic Research Program of China(2012CB720205,2014CB046405)
文摘Predicting wind turbine S825 airfoil＇s aerodynamic performance is crucial to improving its energy efficiency and reducing its environmental impact. In this paper, a numerical simulation on the wind turbine S825 airfoil is con- ducted with k-to turbulence model at different attack angles. By comparing with experimental data, a new method of modifying k-to model is proposed. A modifying function is proposed to limit the production term in ω equation based on fluid rotation and deformation. This method improves turbulent viscosity and decreases separating re- gion when the airfoil works at large separating conditions. The predictive accuracy could be improved by using the modified k-to turbulence model.
文摘本文从Controller Area Network(CAN)总线的特点出发,通过将CAN总线与机载领域应用最成熟的1553B总线进行对比,分析了在航空领域,尤其是在航空机电系统中,局部采用CAN总线的可行性。然后从可靠性和实时性两个方面指出了CAN总线需要在机载适应性上进行的改进。最后结合国外已经发布的CANaerospace和ARINC825协议,指出了在高层协议方面改进的要点,并简要介绍了在国外飞机上CANaero-space和ARINC825的应用实例。
