Rotary friction welding is a highly effective solid-state technique for joining dissimilar materials,which offers the potential for significant weight reduction without compromising strength.Traditionally,during rotar...Rotary friction welding is a highly effective solid-state technique for joining dissimilar materials,which offers the potential for significant weight reduction without compromising strength.Traditionally,during rotary friction welding,the severely deformed material,or flash,is expelled from the interface and machined away to achieve the desired joint geometry.However,this work introduces a novel approach:trapping the flash within the joint to improve joint properties.The study investigates two different interface geometry combinationsdflat-flat and flat-taper interfaces.Previous research shows that Ni interlayer between steel and titanium can enhance the joint strength.This study builds on the existing knowledge(effect of Ni interlayer)by examining the influence of interface geometry to further improve the dissimilar joint performance.The experimental results,including tensile testing and microstructural characterization,highlight the superior performance of the flat-taper interface.The modified geometry minimizes flash loss,providing a cavity that retains both the flash and the Ni interlayer within the joint.This retention promotes dynamic recrystallization,resulting in refined grain structures near the interface.Moreover,the trapped Ni interlayer effectively prevents the formation of brittle Fe-Ti intermetallic compounds at the dissimilar material interface.The findings reveal that the flat-taper interface improved joint strength by an impressive 105%compared to the flat-flat interface.This innovative geometry modification demonstrates the potential to enhance mechanical properties of dissimilar joints through better flash and interlayer management.展开更多
In this study,the effects of hybridizing micron-sized titanium particles with nano-sized boron carbide particles on the microstructural and mechanical properties of Mg-Ti composite were investigated.Microstructural ch...In this study,the effects of hybridizing micron-sized titanium particles with nano-sized boron carbide particles on the microstructural and mechanical properties of Mg-Ti composite were investigated.Microstructural characterization revealed grain refinement attributed to the presence of uniformly distributed micro-Ti particles embedded with nano-B_(4)C particulates.Electron back scattered diffraction(EBSD)analyses of the Mg-(Ti+B_(4)C)BM hybrid composite showed relatively more localized recrystallized grains and lesser tensile twin fraction,when compared to Mg-Ti.The evaluation of mechanical properties indicated that the best combination of strength and ductility was observed in the Mg-(Ti+B_(4)C)BM hybrid composite.The superior properties of the Mg-(Ti+B_(4)C)BM hybrid composite when compared to Mg-Ti can be attributed to the presence of nano-reinforcement,the uniform distribution of the hybridized particles and the better interfacial bonding between the matrix and the reinforcement particles achieved by nano-B_(4)C addition.展开更多
The microstructure and misorientation of ultrathin hot strip were analyzed by CSP technology using electron back scattered diffraction (EBSD) method and Autoforge finite element program. The experimental results showe...The microstructure and misorientation of ultrathin hot strip were analyzed by CSP technology using electron back scattered diffraction (EBSD) method and Autoforge finite element program. The experimental results showed that the finishing hot rolling microstructures were the mixture of recrystallized and deformed austenite. After phase transformation, ferrite grains embody substructures and dislocations, leading to the high strength and relatively low elongation rate of the ultrathin hot strip. The FEM simulation of strain mode and distribution in deformation area has been fulfilled. The simulation results are in good agreement with the theoretical analysis and experimental results.展开更多
The recrystallization behavior of 98.5% cold rolled high purity aluminum foils annealed at 300 ℃ was investigated,and the evolution of the microstructures was followed by electron back scattered diffraction(EBSD).The...The recrystallization behavior of 98.5% cold rolled high purity aluminum foils annealed at 300 ℃ was investigated,and the evolution of the microstructures was followed by electron back scattered diffraction(EBSD).The results show that the recrystallization process of the high purity aluminum foils at 300 ℃ is a mixture of discontinuous-and continuous-recrystallization.The orientations of the recrystallization nuclei include not only the cube orientation,but also other orientations such as some near deformation texture components which are the results of strong recovery process.However,such continuously recrystallized grains are usually associated with relatively high free energy,so they would be consumed by the discontinuously-recrystallized grains(cube-oriented grains)in subsequent annealing.On the other hand,the pattern quality index of recrystallized grains shows dependence on the crystal orientation which might introduce some errors into evaluating volume fraction of recrystallization by integrating pattern quality index of EBSD.展开更多
In this study,we utilized an innovative pathway to obtain exceptional resistance to the cavitation erosion–corrosion behavior by combining surface texturing with severe surface deformation.Severe surface deformation ...In this study,we utilized an innovative pathway to obtain exceptional resistance to the cavitation erosion–corrosion behavior by combining surface texturing with severe surface deformation.Severe surface deformation was carried out using stationary friction process(SFP)followed by micro-texturing through a micro-imprinting approach.The textured sample after processing(SFP+T)had erosion resistance that was 6–7 times greater than that of the as-cast sample under ultrasonic cavitation conditions.In addition,the SFP+T sample was able to sustain a similar trend in the erosion–corrosion medium as well.Furthermore,the flow field characteristics of textured and nontextured samples were investigated using numerical calculations in ANSYS-Fluent.The remarkable improvement in erosion–corrosion resistance was attributed to the finer grains and fluid flow distribution in the textured surface.展开更多
文摘Rotary friction welding is a highly effective solid-state technique for joining dissimilar materials,which offers the potential for significant weight reduction without compromising strength.Traditionally,during rotary friction welding,the severely deformed material,or flash,is expelled from the interface and machined away to achieve the desired joint geometry.However,this work introduces a novel approach:trapping the flash within the joint to improve joint properties.The study investigates two different interface geometry combinationsdflat-flat and flat-taper interfaces.Previous research shows that Ni interlayer between steel and titanium can enhance the joint strength.This study builds on the existing knowledge(effect of Ni interlayer)by examining the influence of interface geometry to further improve the dissimilar joint performance.The experimental results,including tensile testing and microstructural characterization,highlight the superior performance of the flat-taper interface.The modified geometry minimizes flash loss,providing a cavity that retains both the flash and the Ni interlayer within the joint.This retention promotes dynamic recrystallization,resulting in refined grain structures near the interface.Moreover,the trapped Ni interlayer effectively prevents the formation of brittle Fe-Ti intermetallic compounds at the dissimilar material interface.The findings reveal that the flat-taper interface improved joint strength by an impressive 105%compared to the flat-flat interface.This innovative geometry modification demonstrates the potential to enhance mechanical properties of dissimilar joints through better flash and interlayer management.
文摘In this study,the effects of hybridizing micron-sized titanium particles with nano-sized boron carbide particles on the microstructural and mechanical properties of Mg-Ti composite were investigated.Microstructural characterization revealed grain refinement attributed to the presence of uniformly distributed micro-Ti particles embedded with nano-B_(4)C particulates.Electron back scattered diffraction(EBSD)analyses of the Mg-(Ti+B_(4)C)BM hybrid composite showed relatively more localized recrystallized grains and lesser tensile twin fraction,when compared to Mg-Ti.The evaluation of mechanical properties indicated that the best combination of strength and ductility was observed in the Mg-(Ti+B_(4)C)BM hybrid composite.The superior properties of the Mg-(Ti+B_(4)C)BM hybrid composite when compared to Mg-Ti can be attributed to the presence of nano-reinforcement,the uniform distribution of the hybridized particles and the better interfacial bonding between the matrix and the reinforcement particles achieved by nano-B_(4)C addition.
基金This research is supported by the State Foundation for Key Projects, Fundamental Research on New Generation of Steels (No.G1998061500)
文摘The microstructure and misorientation of ultrathin hot strip were analyzed by CSP technology using electron back scattered diffraction (EBSD) method and Autoforge finite element program. The experimental results showed that the finishing hot rolling microstructures were the mixture of recrystallized and deformed austenite. After phase transformation, ferrite grains embody substructures and dislocations, leading to the high strength and relatively low elongation rate of the ultrathin hot strip. The FEM simulation of strain mode and distribution in deformation area has been fulfilled. The simulation results are in good agreement with the theoretical analysis and experimental results.
基金Project(2004053304) supported by the PhD Program Foundation of Education Ministry of China
文摘The recrystallization behavior of 98.5% cold rolled high purity aluminum foils annealed at 300 ℃ was investigated,and the evolution of the microstructures was followed by electron back scattered diffraction(EBSD).The results show that the recrystallization process of the high purity aluminum foils at 300 ℃ is a mixture of discontinuous-and continuous-recrystallization.The orientations of the recrystallization nuclei include not only the cube orientation,but also other orientations such as some near deformation texture components which are the results of strong recovery process.However,such continuously recrystallized grains are usually associated with relatively high free energy,so they would be consumed by the discontinuously-recrystallized grains(cube-oriented grains)in subsequent annealing.On the other hand,the pattern quality index of recrystallized grains shows dependence on the crystal orientation which might introduce some errors into evaluating volume fraction of recrystallization by integrating pattern quality index of EBSD.
文摘In this study,we utilized an innovative pathway to obtain exceptional resistance to the cavitation erosion–corrosion behavior by combining surface texturing with severe surface deformation.Severe surface deformation was carried out using stationary friction process(SFP)followed by micro-texturing through a micro-imprinting approach.The textured sample after processing(SFP+T)had erosion resistance that was 6–7 times greater than that of the as-cast sample under ultrasonic cavitation conditions.In addition,the SFP+T sample was able to sustain a similar trend in the erosion–corrosion medium as well.Furthermore,the flow field characteristics of textured and nontextured samples were investigated using numerical calculations in ANSYS-Fluent.The remarkable improvement in erosion–corrosion resistance was attributed to the finer grains and fluid flow distribution in the textured surface.
