Nimonic 80A is a nickel-chromium alloy which is strengthened by additions of titanium and aluminium. The alloy is used for high temperature, high strength applications. Wire shaped Nimonic 80A samples are resistively ...Nimonic 80A is a nickel-chromium alloy which is strengthened by additions of titanium and aluminium. The alloy is used for high temperature, high strength applications. Wire shaped Nimonic 80A samples are resistively volume heated as part of a fast capacitor discharge circuit. Time resolved measurements with sub-μs resolution of current through the specimen are performed with a Pearson probe, voltage drop across the specimen is measured with knife-edge contacts and ohmic voltage dividers and the radiance temperature of the sample with a pyrometer. These measurements allow to determine heat of fusion as well as heat capacity and electrical resistivity at initial geometry of Nimonic 80A as a function of temperature in the solid and in the liquid phase up to 2400 K.展开更多
The effects of the cutting parameters （cutting speed, feed rate and depth of cut） on the surface roughness in machining the Nimonic C-263 alloy were investigated. The experiments were conducted using Taguchi＇s expe...The effects of the cutting parameters （cutting speed, feed rate and depth of cut） on the surface roughness in machining the Nimonic C-263 alloy were investigated. The experiments were conducted using Taguchi＇s experimental design. The effect of cutting parameters on surface roughness was evaluated and the optimum cutting conditions for minimizing the surface roughness were determined. A second order model was established between the cutting parameters and surface roughness, using the response surface methodology. The experimental results revealed that among the parameters considered, the feed rate is the most significant which influences the surface roughness, followed by the cutting speed. The predicted values and measured values are fairly close, which indicates that the developed model can be effectively used to predict the surface roughness in machining the Nimonic C-263 alloy. The predicted values are validated using the additive law.展开更多
The paper proposes a simulated 3D Finite Element Model(FEM)for drilling of Nickel based super alloy known as Nimonic C-263.The Lagrangian finite element model-based simulations were performed to determine the thrust f...The paper proposes a simulated 3D Finite Element Model(FEM)for drilling of Nickel based super alloy known as Nimonic C-263.The Lagrangian finite element model-based simulations were performed to determine the thrust force,temperature generation,effective stress,and effective strain.The simulations were performed according to the L27 orthogonal array.A perfect plastic work piece was assumed,and the shape is considered to be cylindrical.The spindle speed,feed rate,and point angle were considered as the input parameters.The work piece was modeled by Johnson-Cook(JC)material model and tungsten carbide(WC)was chosen as the drill bit and the body was assumed to be rigid.The demonstrative results of the thrust force and the temperature at drill bit cutting edge were substantiated with the simulated results and a percentage error was observed within 10%.Further,simulated results of effective stress and strain were also observed.展开更多
Microstructural change,stress rupture property,deformation and fracture mechanisms of Nimonic 105 superalloy at 750℃have been studied.Experimental results showed that the stress rupture strength of the alloy at 750℃...Microstructural change,stress rupture property,deformation and fracture mechanisms of Nimonic 105 superalloy at 750℃have been studied.Experimental results showed that the stress rupture strength of the alloy at 750℃ for 10^(5)h is about 200 MPa.γ'precipitates and M_(23)C_(6)carbides grew gradually with prolonging the rupture time,while no significant change was observed in MC carbide morphology.After stress rupture test at 750℃ and 250 MPa for 23,341 h,a transition from spherical to cuboidal morphology of γ'precipitates was found,and nearly continuous chains of M_(23)C_(6)carbides formed on the grain boundary.Orowan looping and strongly coupled dislocation pairs cutting and microtwinning were the dominant deformation mechanisms at 750℃ and 350-450 MPa,while the main deformation mode was Orowan looping at 750℃ and 250 MPa.The failure of the alloy was mainly attributed to the nucleation,growth and interlinkage of voids.展开更多
过渡金属氮化物因具有高的导电性、可调节的能带结构以及优异的稳定性,成为高性能析氢反应(HER)电催化剂的理想选择。然而,在合成过程中,过高或过低的氮化温度会导致材料的结构发生改变,进而影响其电化学活性。因此,调控适当的氮化温度...过渡金属氮化物因具有高的导电性、可调节的能带结构以及优异的稳定性,成为高性能析氢反应(HER)电催化剂的理想选择。然而,在合成过程中,过高或过低的氮化温度会导致材料的结构发生改变,进而影响其电化学活性。因此,调控适当的氮化温度至关重要。通过水热-煅烧工艺成功制备了自支撑Ni_(3)N/NiMoN异质结纳米片阵列(Ni_(3)N/NiMoN-450@CC)。采用XRD,SEM,XPS等测试手段对材料的形貌和组分进行表征,结果表明,Ni_(3)N/NiMoN异质结纳米片在碳布上均匀排列并形成阵列结构。通过线性扫描伏安法(LSV)和循环伏安法(CV)对材料的电化学性能进行观察,测试结果说明,Ni_(3)N/NiMoN-450@CC催化剂在碱性电解质中表现出良好的HER催化活性,电流密度为10 m A·cm-2时,其过电位为34 mV,并且在连续测试48 h后,电流密度几乎不变。展开更多
基金This work was financially supported by the Austrian "Forschungsfrderungsgesellschaft mbH", Krntner Strasse 21-23, 1010 Vienna, under contract No. 810999.
文摘Nimonic 80A is a nickel-chromium alloy which is strengthened by additions of titanium and aluminium. The alloy is used for high temperature, high strength applications. Wire shaped Nimonic 80A samples are resistively volume heated as part of a fast capacitor discharge circuit. Time resolved measurements with sub-μs resolution of current through the specimen are performed with a Pearson probe, voltage drop across the specimen is measured with knife-edge contacts and ohmic voltage dividers and the radiance temperature of the sample with a pyrometer. These measurements allow to determine heat of fusion as well as heat capacity and electrical resistivity at initial geometry of Nimonic 80A as a function of temperature in the solid and in the liquid phase up to 2400 K.
文摘The effects of the cutting parameters （cutting speed, feed rate and depth of cut） on the surface roughness in machining the Nimonic C-263 alloy were investigated. The experiments were conducted using Taguchi＇s experimental design. The effect of cutting parameters on surface roughness was evaluated and the optimum cutting conditions for minimizing the surface roughness were determined. A second order model was established between the cutting parameters and surface roughness, using the response surface methodology. The experimental results revealed that among the parameters considered, the feed rate is the most significant which influences the surface roughness, followed by the cutting speed. The predicted values and measured values are fairly close, which indicates that the developed model can be effectively used to predict the surface roughness in machining the Nimonic C-263 alloy. The predicted values are validated using the additive law.
文摘The paper proposes a simulated 3D Finite Element Model(FEM)for drilling of Nickel based super alloy known as Nimonic C-263.The Lagrangian finite element model-based simulations were performed to determine the thrust force,temperature generation,effective stress,and effective strain.The simulations were performed according to the L27 orthogonal array.A perfect plastic work piece was assumed,and the shape is considered to be cylindrical.The spindle speed,feed rate,and point angle were considered as the input parameters.The work piece was modeled by Johnson-Cook(JC)material model and tungsten carbide(WC)was chosen as the drill bit and the body was assumed to be rigid.The demonstrative results of the thrust force and the temperature at drill bit cutting edge were substantiated with the simulated results and a percentage error was observed within 10%.Further,simulated results of effective stress and strain were also observed.
基金the National Key Research and Develop plan,China(No.2016YFB0300203).
文摘Microstructural change,stress rupture property,deformation and fracture mechanisms of Nimonic 105 superalloy at 750℃have been studied.Experimental results showed that the stress rupture strength of the alloy at 750℃ for 10^(5)h is about 200 MPa.γ'precipitates and M_(23)C_(6)carbides grew gradually with prolonging the rupture time,while no significant change was observed in MC carbide morphology.After stress rupture test at 750℃ and 250 MPa for 23,341 h,a transition from spherical to cuboidal morphology of γ'precipitates was found,and nearly continuous chains of M_(23)C_(6)carbides formed on the grain boundary.Orowan looping and strongly coupled dislocation pairs cutting and microtwinning were the dominant deformation mechanisms at 750℃ and 350-450 MPa,while the main deformation mode was Orowan looping at 750℃ and 250 MPa.The failure of the alloy was mainly attributed to the nucleation,growth and interlinkage of voids.
文摘过渡金属氮化物因具有高的导电性、可调节的能带结构以及优异的稳定性,成为高性能析氢反应(HER)电催化剂的理想选择。然而,在合成过程中,过高或过低的氮化温度会导致材料的结构发生改变,进而影响其电化学活性。因此,调控适当的氮化温度至关重要。通过水热-煅烧工艺成功制备了自支撑Ni_(3)N/NiMoN异质结纳米片阵列(Ni_(3)N/NiMoN-450@CC)。采用XRD,SEM,XPS等测试手段对材料的形貌和组分进行表征,结果表明,Ni_(3)N/NiMoN异质结纳米片在碳布上均匀排列并形成阵列结构。通过线性扫描伏安法(LSV)和循环伏安法(CV)对材料的电化学性能进行观察,测试结果说明,Ni_(3)N/NiMoN-450@CC催化剂在碱性电解质中表现出良好的HER催化活性,电流密度为10 m A·cm-2时,其过电位为34 mV,并且在连续测试48 h后,电流密度几乎不变。
