采用热台原位加热法系统研究了不同保护气体流量对润湿铺展过程、润湿铺展最大半径、润湿铺展动力学以及界面组织结构的影响.保护气体为氩气,保护气体流量分别为5,10,15 m L/s;加热曲线设定最高温度为1 273K,保温时间120 s;采用扫描电...采用热台原位加热法系统研究了不同保护气体流量对润湿铺展过程、润湿铺展最大半径、润湿铺展动力学以及界面组织结构的影响.保护气体为氩气,保护气体流量分别为5,10,15 m L/s;加热曲线设定最高温度为1 273K,保温时间120 s;采用扫描电镜、能谱分析、光学显微镜等分析了界面组织结构.结果表明,保护气体流量为15m L/s时,润湿铺展等效半径最大,原始半径0.9 mm的钎料铺展半径达到约1.4 mm.各种保护条件下,Ag Cu Ti/Ti Al体系的润湿铺展动力学过程相似,铺展半径与时间之间呈n次幂关系,即rn^kt;润湿铺展中钎料熔敷/Ti Al的界面结构为:残余钎料的富银相/Al Cu Ti三元相层(Al Cu2Ti,Al Cu Ti,Ti3Al)/Ti Al母材,保护条件对其影响不大.展开更多
The ZrO2 ceranfic was successfully jointed to stainless steel by vacuum brazing with active filler metal. The AgCuTi active filler metal was used and the joining was performed at a temperature of 850 ℃ for 10 rain. T...The ZrO2 ceranfic was successfully jointed to stainless steel by vacuum brazing with active filler metal. The AgCuTi active filler metal was used and the joining was performed at a temperature of 850 ℃ for 10 rain. The microstructures of the joints were characterized by metallographic microscopy, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. Metallographic microscopy analysis shows that the morphology of the cross section was a sandwich structure and the TiO is observed in the surface of ZrO2/ stainless steel. The diffusion and enrichment of the elements are the key roles in the brazing of ZrO2 ceramic and stainless steel. The formation of TiCu compounds inhibited the further diffusion of titanium into stainless steel or the ZrO2 ceramic to form TiO compound. In the experimental conditions, the average tensile strength is 80MPa for the joint of ZrO2 ceramic / AgCuTi/ stainless steel systems. A complete joint is formed between the ZrO2 ceramic and stainless steel with the leakage rate at the degree of 10 ^-12 Pa · m^3/s.展开更多
AgCuTi-based composite fillers reinforced with Carbon Nanotubes(CNTs) were prepared by mechanical ball milling and ultrasonic agitation. The morphological features, chemical components, and melting characteristics of ...AgCuTi-based composite fillers reinforced with Carbon Nanotubes(CNTs) were prepared by mechanical ball milling and ultrasonic agitation. The morphological features, chemical components, and melting characteristics of the composite fillers with different content of CNTs addition were investigated using Field Emission Scanning Electron Microscopy(FESEM), XRay Diffraction(XRD) and a Differential Scanning Calorimeter(DSC). After being heated at 900 ℃, the microstructure of the composite fillers was examined through FESEM and Transmission Electron Microscopy(TEM) to analyze the interfacial characteristics in the AgCuTi-CNTs system.The microstructures of the composite fillers with 0.5 wt% CNTs and 0.1 wt% CNTs were compared. It was found that 0.5 wt% CNTs were favorable for dispersive distribution of the structure.Nano-sized TiC particles formed in the reaction of CNTs with Ti, resulting in the transformation of TiCu;with high Ti content and Ti;Cu;phases to TiCu;phase with low Ti content. Additionally,the microstructure evolution of the composite fillers was studied by changing the ratio of Ti/CNTs.Results showed that CNTs significantly influenced the wettability of the AgCuTi filler. After addition of 0.3 wt% of CNTs, the spreading area of the composite filler on the C/C composite increased by 146.0%.展开更多
The dissimilar materials joining of C/C composites to T2 copper were performed successfully by thermo-compensated Resistance Brazing Welding(RBW)with AgCuTi filler powder.The interfacial microstructure,phase compositi...The dissimilar materials joining of C/C composites to T2 copper were performed successfully by thermo-compensated Resistance Brazing Welding(RBW)with AgCuTi filler powder.The interfacial microstructure,phase composition,and shear strength of the resistance brazed joints were investigated by the relevant analysis method.Experiment results indicated that the order affecting the shear strength of the C/C-Cu joint was welding current,welding pressure,and welding time in turn.The shear strength of backward thermo-compensated RBW was higher than that of forward thermo-compensated RBW due to the Peltier effect.The maximum shear strength of the C/C-Cu joint was 11.56 MPa in the optimized welding parameter with welding current of 8.0 kA,welding time of 60 ms,and welding pressure of 0.10 MPa by backward thermo-compensated RBW.The interface structure at the resistance brazed joint with this welding parameter was C/C composites/TiC/Cu(s.s)/T2 copper.The TiC phase was verified at the interface of the brazed joint by Scanning Electron Microscope(SEM),Energy-Dispersive X-ray Spectrometer(EDS),and X-ray Diffraction(XRD).Considerable fractures occurred in the C/C composites and partial fracture occurred at the interfacial reaction layer.展开更多
文摘采用热台原位加热法系统研究了不同保护气体流量对润湿铺展过程、润湿铺展最大半径、润湿铺展动力学以及界面组织结构的影响.保护气体为氩气,保护气体流量分别为5,10,15 m L/s;加热曲线设定最高温度为1 273K,保温时间120 s;采用扫描电镜、能谱分析、光学显微镜等分析了界面组织结构.结果表明,保护气体流量为15m L/s时,润湿铺展等效半径最大,原始半径0.9 mm的钎料铺展半径达到约1.4 mm.各种保护条件下,Ag Cu Ti/Ti Al体系的润湿铺展动力学过程相似,铺展半径与时间之间呈n次幂关系,即rn^kt;润湿铺展中钎料熔敷/Ti Al的界面结构为:残余钎料的富银相/Al Cu Ti三元相层(Al Cu2Ti,Al Cu Ti,Ti3Al)/Ti Al母材,保护条件对其影响不大.
基金supported by the National Key R&D Program of China(Grant No.2017YFB0305700)
文摘The ZrO2 ceranfic was successfully jointed to stainless steel by vacuum brazing with active filler metal. The AgCuTi active filler metal was used and the joining was performed at a temperature of 850 ℃ for 10 rain. The microstructures of the joints were characterized by metallographic microscopy, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. Metallographic microscopy analysis shows that the morphology of the cross section was a sandwich structure and the TiO is observed in the surface of ZrO2/ stainless steel. The diffusion and enrichment of the elements are the key roles in the brazing of ZrO2 ceramic and stainless steel. The formation of TiCu compounds inhibited the further diffusion of titanium into stainless steel or the ZrO2 ceramic to form TiO compound. In the experimental conditions, the average tensile strength is 80MPa for the joint of ZrO2 ceramic / AgCuTi/ stainless steel systems. A complete joint is formed between the ZrO2 ceramic and stainless steel with the leakage rate at the degree of 10 ^-12 Pa · m^3/s.
基金co-funded by the National Natural Science Foundation of China(Nos.51875130 and 51775138)the Shandong Provincial Natural Science Foundation of China(No.ZR2019MEE091)。
文摘AgCuTi-based composite fillers reinforced with Carbon Nanotubes(CNTs) were prepared by mechanical ball milling and ultrasonic agitation. The morphological features, chemical components, and melting characteristics of the composite fillers with different content of CNTs addition were investigated using Field Emission Scanning Electron Microscopy(FESEM), XRay Diffraction(XRD) and a Differential Scanning Calorimeter(DSC). After being heated at 900 ℃, the microstructure of the composite fillers was examined through FESEM and Transmission Electron Microscopy(TEM) to analyze the interfacial characteristics in the AgCuTi-CNTs system.The microstructures of the composite fillers with 0.5 wt% CNTs and 0.1 wt% CNTs were compared. It was found that 0.5 wt% CNTs were favorable for dispersive distribution of the structure.Nano-sized TiC particles formed in the reaction of CNTs with Ti, resulting in the transformation of TiCu;with high Ti content and Ti;Cu;phases to TiCu;phase with low Ti content. Additionally,the microstructure evolution of the composite fillers was studied by changing the ratio of Ti/CNTs.Results showed that CNTs significantly influenced the wettability of the AgCuTi filler. After addition of 0.3 wt% of CNTs, the spreading area of the composite filler on the C/C composite increased by 146.0%.
基金supported by the National Natural Science Foundation of China(No.52175305)the Industrial Innovation Major Technology Global Unveiling Project of Jining City,China(No.2022JBZP004)the New and Old Kinetic Energy Conversion Major Industrial Research Projects in Shandong Province in 2021,China.
文摘The dissimilar materials joining of C/C composites to T2 copper were performed successfully by thermo-compensated Resistance Brazing Welding(RBW)with AgCuTi filler powder.The interfacial microstructure,phase composition,and shear strength of the resistance brazed joints were investigated by the relevant analysis method.Experiment results indicated that the order affecting the shear strength of the C/C-Cu joint was welding current,welding pressure,and welding time in turn.The shear strength of backward thermo-compensated RBW was higher than that of forward thermo-compensated RBW due to the Peltier effect.The maximum shear strength of the C/C-Cu joint was 11.56 MPa in the optimized welding parameter with welding current of 8.0 kA,welding time of 60 ms,and welding pressure of 0.10 MPa by backward thermo-compensated RBW.The interface structure at the resistance brazed joint with this welding parameter was C/C composites/TiC/Cu(s.s)/T2 copper.The TiC phase was verified at the interface of the brazed joint by Scanning Electron Microscope(SEM),Energy-Dispersive X-ray Spectrometer(EDS),and X-ray Diffraction(XRD).Considerable fractures occurred in the C/C composites and partial fracture occurred at the interfacial reaction layer.
