The impact of cold rolling deformation,which was introduced after solid solution and before aging treatment,on microstructure evolution and mechanical properties of the as-extruded spray formed Al−9.8Zn−2.3Mg−1.73Cu−0...The impact of cold rolling deformation,which was introduced after solid solution and before aging treatment,on microstructure evolution and mechanical properties of the as-extruded spray formed Al−9.8Zn−2.3Mg−1.73Cu−0.13Cr(wt.%)alloy,was investigated.SEM,TEM,and EBSD were used to analyze the microstructures,and tensile tests were conducted to assess mechanical properties.The results indicate that the D1-T6 sample,subjected to 25%cold rolling deformation,exhibits finer grains(3.35μm)compared to the D0-T6 sample(grain size of 4.23μm)without cold rolling.Cold rolling refines the grains that grow in solution treatment.Due to the combined effects of finer and more dispersed precipitates,higher dislocation density and smaller grains,the yield strength and ultimate tensile strength of the D1-T6 sample can reach 663 and 737 MPa,respectively.In comparison to the as-extruded and D0-T6 samples,the yield strength of the D1-T6 sample increases by 415 and 92 MPa,respectively.展开更多
Ti-6Al-4V alloy was processed by wet shot peening with ceramic beads. The effects of the shot peened intensity on the microstructure, surface morphology, and residual stress were investigated. A tensile-tensile fatigu...Ti-6Al-4V alloy was processed by wet shot peening with ceramic beads. The effects of the shot peened intensity on the microstructure, surface morphology, and residual stress were investigated. A tensile-tensile fatigue test was performed and the fracture mechanism was proposed. The results demonstrate that the surface roughness after wet shot peening is obviously lower than that after dry shot peening. With the increase of the shot peened intensity, the depth of the residual stress layer increases to 250 ktrn, and the maximum stress in this layer increases to -895 MPa. The fatigue strength also increases by 12.4% because of the wet shot peening treatment. The dislocation density of the surface layer is significantly enhanced after the wet shot peening with ceramic beads. The microstructure of the surface layer is obviously refined into ultra-fine grains.展开更多
A metallic glass coating with the composition of Fe51.33Cr14.9Mo25.67Y3.4C3.44B1.26 (mole fraction, %) on the Q235 stainless steel was developed by the detonation gun (D-gun) spraying process. The microstructure a...A metallic glass coating with the composition of Fe51.33Cr14.9Mo25.67Y3.4C3.44B1.26 (mole fraction, %) on the Q235 stainless steel was developed by the detonation gun (D-gun) spraying process. The microstructure and the phase aggregate were analyzed by scanning electron microscopy and X-ray diffractometry, respectively. Microhardness, wear resistance and corrosion behavior were assessed using a Vickers microhardness tester, a ball-on-disk wear testing machine and the electrochemical measurement method, respectively. Microstructural studies show that the coatings possess a densely layered structure with the porosity less than 2.1%. The tribological behavior of the coatings examined under dry conditions shows that their relative wear resistance is five times higher than that of the substrate material. Both adhesive wear and abrasive wear contribute to the friction, but the former is the dominant wear mechanism of the metallic glass coatings. The coatings exhibit low passive current density and extremely wide passive region in 3.5% NaCl solution, thus indicating excellent corrosion resistance.展开更多
The NiA1 Cr(Mo) (Hf, Dy) hypoeutectic alloys were prepared by conventional casting and injection casting techniques respectively, and their microstructure and room temperature mechanical properties were investigat...The NiA1 Cr(Mo) (Hf, Dy) hypoeutectic alloys were prepared by conventional casting and injection casting techniques respectively, and their microstructure and room temperature mechanical properties were investigated. The results reveal that with the addition of Hf and Dy, the Ni2AIHf Heusler phase and NisDy phase form along the NiAI/Cr(Mo) phase boundaries in intercellular region. By the injection casting method, some Ni2AIHf Heusler phase and NisDy phase transform into Hf and Dy solid solutions, respectively. Moreover, the microstructure of the alloy gets good optimization, which can be characterized by the fine interlamellar spacing, high proportion of eutectic cell area and homogeneously distributed fine Ni2AIHf, NisDy, Hf solid solution and Dy solid solutions. Compared with conventional-cast alloy, the room temperature mechanical properties of injection-cast alloy are improved obviously.展开更多
With the aim to improve the strength of Al-Zn-Mg-Cu alloy,the alloy billet containing Mn was produced by spray forming method,and the microstructural features were investigated using X-ray diffraction(XRD),optical m...With the aim to improve the strength of Al-Zn-Mg-Cu alloy,the alloy billet containing Mn was produced by spray forming method,and the microstructural features were investigated using X-ray diffraction(XRD),optical microscopy(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM) and differential scanning calorimetry(DSC).The results show that the billet mainly consists of fine equiaxial grains of MgZn2 and Al6Mn with size ranging from 5 μm to 25 μm.Nano-scaled MgZn2 is dispersed in the as-sprayed alloy,primary Al6Mn particles are precipitated at grain boundaries with an average size of 5 μm.A few CuAl2,Al3Zr and eutectic are also found in as-sprayed Al alloy.The volume fraction of the porosity is about 12%.DSC result indicates that most of the solutes are precipitated during spray forming process,and no obviously thermal effects occur below 450 ℃.Both matrix grains and Al6Mn particles grow monotonously with the increase of annealing temperature,but the growth rate of Al6Mn particles is markedly lower than that of Al grains,and the matrix grains grow rapidly when the annealing temperature is above 375 ℃.展开更多
TC6 titanium alloy samples are processed by laser shock peening (LSP). Then, some samples are vacu- um annealed at 623 K for 10 h for the study on the thermost.ablity of the nanostructure produced by LSP. The charac...TC6 titanium alloy samples are processed by laser shock peening (LSP). Then, some samples are vacu- um annealed at 623 K for 10 h for the study on the thermost.ablity of the nanostructure produced by LSP. The characteristics of the strengthened layer and nanostructure are studied by atomic force microscopy(AFM), scan- ning electron microscope (SEM), electron backscatter diffraction(EBSD), X-ray diffraction(XRD), and transmis- sion electron microscopy(TEM) appliances, meanwhile the enhanced microhardness is tested at cross section. AFM of the processed surface indicates that the deformation is approximately uniform, and LSP slightly increases the roughness. SEM and EBSD of the strengthened cross section show that a phases are compressed to strip- shaped, a proportion of a and ~ phases is shattered to smaller phases from surface to 200 ttm in depth. The sur- face XRD shows that although there is no new produced phase during LSP, the grain size refinement and the in- troduction of lattice micro-strains lead to the broadened peak. The TEM photographs and diffraction patterns in- dicate that the shock wave provides high strain rate deformation and leads to the formation of nanocrystal. Com- pared with the samples before annealing, the dislocation density is lower and the grain-boundary is more distinct in the annealed samples, but the nanocrystal size does not grow bigger after annealing. The microhardness measurement indicates that LSP improves the microhardness of TC6 for about 12.2% on the surface, and the layer affected by LSP is about 500/~m in depth. The microhardness after annealing is 10 HVo.5 lower, but the affected depth does not change. The thermostable study shows that the strengthened layer of TC6 processed by LSP is stable at 623 K. The strengthened thermostable layer can significantly improve the fatigue resistance, wear resis- tance and stress corrosion resistance of the titanium alloy. The study results break the USA standard AMS2546 that titanium parts after LSP are subjected in subsequent processing within 589 K.展开更多
The airflow in the reed groove of the air jet loom for the weft insertion includes the jet stream from the relay nozzle, the back leak stream from the reed, and the diffusion stream from the open side. The air velocit...The airflow in the reed groove of the air jet loom for the weft insertion includes the jet stream from the relay nozzle, the back leak stream from the reed, and the diffusion stream from the open side. The air velocity in the reed groove can be measured to analyze the influence of process parameters during the weft insertion. The relation between the air velocity and the relay nozzle distance, the jet angle or the supply pressure of the relay nozzle can be studied. In this paper, the pitot tube is applied to measure the air velocity in reed groove by the instrument designed. And the results indicate that the air velocity fluctuation in the reed groove is strong, and can drop from 150 m·s-1 to 80 m·s-1 drastically.展开更多
A new kind of multi-dimensional WC-10Co4Cr coating which is composed of nano,submicron,micron WC grains and CoCr alloy,was developed by high velocity oxy-fuel(HVOF)spraying.Porosity,microhardness,fracture toughness an...A new kind of multi-dimensional WC-10Co4Cr coating which is composed of nano,submicron,micron WC grains and CoCr alloy,was developed by high velocity oxy-fuel(HVOF)spraying.Porosity,microhardness,fracture toughness and cavitation erosion resistance of the multi-dimensional coating were investigated in comparison with the bimodal and nanostructured WC?10Co4Cr coatings.Moreover,the cavitation erosion behavior and mechanism of the multi-dimensional coating were explored.Results show that HVOF sprayed multi-dimensional WC-10Co4Cr coating possesses low porosity(≤0.32%)and high fracture toughness without obvious nano WC decarburization during spraying.Furthermore,it is discovered that the multi-dimensional WC-10Co4Cr coating exhibits the best cavitation erosion resistance which is enhanced by approximately 28%and 34%,respectively,compared with the nanostructured and bimodal coatings in fresh water.The superior cavitation resistance of multi-dimensional WC-10Co4Cr coating may originate from the unique micro?nano structure and excellent properties,which can effectively obstruct the formation and propagation of cavitation erosion cracks.展开更多
The watar jet impulse is brought forward to study the traction force of the water jet to the flying weft in water-jet looms. The distribution of the water jet impulse in the shed is tested by a sensor, and the influen...The watar jet impulse is brought forward to study the traction force of the water jet to the flying weft in water-jet looms. The distribution of the water jet impulse in the shed is tested by a sensor, and the influence of water jet parameters on the water jet impulse is analyzed.展开更多
In order to study the propulsive force on the water-jet to the flying weft in water-jet looms, a dynamic model has been established. Based on the analysis and example testing, an experiential formula of the propulsive...In order to study the propulsive force on the water-jet to the flying weft in water-jet looms, a dynamic model has been established. Based on the analysis and example testing, an experiential formula of the propulsive force of the water-jet to the flying weft is obtained for the first time. The formula will profit the further research of the water-jet weft insertion and the production of textile.展开更多
This article deals with the energy efficiency of textile weaving machines. A method based on exergy balances has been developed at the Institute for Textile Technology RWTH Aachen University (ITA), Aachen, Germany i...This article deals with the energy efficiency of textile weaving machines. A method based on exergy balances has been developed at the Institute for Textile Technology RWTH Aachen University (ITA), Aachen, Germany in order to improve energy efficiency textile machines. The relay nozzles of the air-jet weaving technology need up to 80% of the energy of the weaving machine. At ITA, a new nozzle concept was developed. The developed geometry is a so called High-Volume-Low-Pressure nozzle (HVLP nozzle), based on convergent nozzle aerodynamic theory. With this concept, energy savings up to 30% are possible.展开更多
In the water jet looms, the distribution of the speed of water jet at the axis of the shed and its regularity are obtained by the Laser Doppler Tester. Based on the above, the water jet system is analyzed and the main...In the water jet looms, the distribution of the speed of water jet at the axis of the shed and its regularity are obtained by the Laser Doppler Tester. Based on the above, the water jet system is analyzed and the main effective approaches to increase the filling insertion rate and to widen the reed space of the loom are pointed out.展开更多
The extrusion preform of the spray-formed5A12Al alloy was hot rolled using high reduction rolling technology.By means of transmission electron microscopy(TEM),electron backscatter diffraction(EBSD)and energy dispersiv...The extrusion preform of the spray-formed5A12Al alloy was hot rolled using high reduction rolling technology.By means of transmission electron microscopy(TEM),electron backscatter diffraction(EBSD)and energy dispersive spectroscopy(EDS),the microstructure evolution was studied and the strengthening and toughening mechanism was thereby proposed.The results indicate that discontinuous and continuous dynamic recrystallization occurred during the hot rolling deformation of the spray-formed5A12Al alloy.The grain size was significantly refined and the micro-scale grains formed.Partial dynamic recrystallization leads to a significant increase of dislocation density and cellular structure.The Mg atoms were distributed in the Al matrix mainly in the presence of solid solution rather than the formation of precipitate.High solid solution of Mg atoms not only hindered the dislocation motion and increased the density of dislocation,but also exhibited a remarkable solid solution strengthening effect,which contributes to the high strength and high toughness of the as-rolled sheets.The tensile strength and elongation of spray formed5A12Al alloy at room temperature after3passes hot rolling were622MPa and20%,respectively.展开更多
The objective of this research was to investigate the optimum condition for treatment of textile industrial wastewater from water jet loom machine by chemical coagulation and electrocoagulation methods. The variables ...The objective of this research was to investigate the optimum condition for treatment of textile industrial wastewater from water jet loom machine by chemical coagulation and electrocoagulation methods. The variables of chemical coagulation method were type and amount of chemicals, pH and stirring rate. For electrocoagulation method, the variables were electrode materials, electric potential and contact time. It was found that the optimum condition of chemical coagulation method was 10% (w/w) of aqueous solution of aluminum sulphate 80 mL and 0.01% (w/w) of aqueous solution of coagulant aids, cationic polymer 32 mL per 4 L of wastewater at oH 8. The mixture solution was rapidly stirred with 120 rpm for 1 min and then slowly stirred with 20 rpm for 20 rain. The removal efficiency of turbidity, COD and oil content were 88.88%, 85.20% and 77.72%, respectively. For electrocoagulation method, the optimum condition was using aluminum electrode with 35 V and 150 min of contact time. The removal efficiency of turbidity, COD and oil content were 98.86%, 91.63% and 89.84%, respectively. It can be concluded from this study that the textile industrial wastewater treatment from water jet loom machine with electrocoagulation method is more efficient than that with chemical coagulation method.展开更多
Without any preprocessing,polyester fabric has lower ability to hold on water and inks due to the smooth morphology of polyester fibers. Therefore, patterns directly printed with pigment inks have poor color yields an...Without any preprocessing,polyester fabric has lower ability to hold on water and inks due to the smooth morphology of polyester fibers. Therefore, patterns directly printed with pigment inks have poor color yields and bleed easily. Pretreatments of polyester fabric were carried out with atmospheric air plasma under different experimental conditions. After plasma treatment the samples were printed with magenta pigment ink. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses indicated that the enhanced color performance was mainly contributed by not only the etching effect but also oxygen-containing polar groups induced onto fiber surfaces through plasma treatment. Thereby the surface modification of polyester fabrics using atmospheric-pressure air plasma offers a potential way to fabric pretreatment for pigment inkjet printing with the advantages of environmental friendly and energy saving over traditional pretreatment methods.展开更多
Recycled high-strength aluminum alloys have limited use as structural materials due to poor mechanical properties. Spray forming remelting followed by hot extrusion is a promising route for reprocessing 7 xxx alloys. ...Recycled high-strength aluminum alloys have limited use as structural materials due to poor mechanical properties. Spray forming remelting followed by hot extrusion is a promising route for reprocessing 7 xxx alloys. The 7050 alloy machining chips were spray formed, hot extruded, rotary swaged and heat-treated in order to improve mechanical properties. Microstructures, tensile properties and fatigue strength results for a 2.7 mm-diameter recycled wire are presented. Secondary phases and precipitates were investigated by XRD, SEM, EBSD, TEM and DSC. As-swaged and heat-treated(solution and aging) conditions were evaluated. Mechanical properties of both conditions outperformed AA7050 aerospace specification. Substantial grain refinement resulted from the extensive plastic deformation imposed by rotary swaging. Refined micrometric and sub-micrometric Al grains, as well as coarse and fine intermetallic precipitates were observed. Subsequent solution treatment resulted in a homogeneous, recrystallized and equiaxed microstructure with grain size of 9 μm. Nanoscale GP(I) zones and η′ phase precipitates formed after aging at 120 ℃, imparting higher tensile(586 MPa) and fatigue(198 MPa) strengths.展开更多
Analytical examination was made to ascertain the effect of the high pressure water flow on the fabric properties.Polyester/cotton blended cambric was spurted by high pressure water flow. Fabric properties such as hand...Analytical examination was made to ascertain the effect of the high pressure water flow on the fabric properties.Polyester/cotton blended cambric was spurted by high pressure water flow. Fabric properties such as handle,thickness, tensile strength , stiffness and air permeability after the water treatment were investigated.展开更多
基金the support from the National Natural Science Foundation of China(No.52271177)the Science and Technology Innovation Leaders Projects in Hunan Province,China(No.2021RC4036).
文摘The impact of cold rolling deformation,which was introduced after solid solution and before aging treatment,on microstructure evolution and mechanical properties of the as-extruded spray formed Al−9.8Zn−2.3Mg−1.73Cu−0.13Cr(wt.%)alloy,was investigated.SEM,TEM,and EBSD were used to analyze the microstructures,and tensile tests were conducted to assess mechanical properties.The results indicate that the D1-T6 sample,subjected to 25%cold rolling deformation,exhibits finer grains(3.35μm)compared to the D0-T6 sample(grain size of 4.23μm)without cold rolling.Cold rolling refines the grains that grow in solution treatment.Due to the combined effects of finer and more dispersed precipitates,higher dislocation density and smaller grains,the yield strength and ultimate tensile strength of the D1-T6 sample can reach 663 and 737 MPa,respectively.In comparison to the as-extruded and D0-T6 samples,the yield strength of the D1-T6 sample increases by 415 and 92 MPa,respectively.
基金Project(NCET-10-0278)supported by Program for New Century Excellent Talents in University,China
文摘Ti-6Al-4V alloy was processed by wet shot peening with ceramic beads. The effects of the shot peened intensity on the microstructure, surface morphology, and residual stress were investigated. A tensile-tensile fatigue test was performed and the fracture mechanism was proposed. The results demonstrate that the surface roughness after wet shot peening is obviously lower than that after dry shot peening. With the increase of the shot peened intensity, the depth of the residual stress layer increases to 250 ktrn, and the maximum stress in this layer increases to -895 MPa. The fatigue strength also increases by 12.4% because of the wet shot peening treatment. The dislocation density of the surface layer is significantly enhanced after the wet shot peening with ceramic beads. The microstructure of the surface layer is obviously refined into ultra-fine grains.
基金Project(51301205)supported by the National Natural Science Foundation of ChinaProject(20130162120001)supported by the Doctoral Program of Higher Education of China+2 种基金Project(K1502003-11)supported by the Changsha Municipal Major Science and Technology Program,ChinaProject(K1406012-11)supported by the Changsha Municipal Science and Technology Plan,ChinaProject(2016CX003)supported by the Innovation-driven Plan in Central South University,China
文摘A metallic glass coating with the composition of Fe51.33Cr14.9Mo25.67Y3.4C3.44B1.26 (mole fraction, %) on the Q235 stainless steel was developed by the detonation gun (D-gun) spraying process. The microstructure and the phase aggregate were analyzed by scanning electron microscopy and X-ray diffractometry, respectively. Microhardness, wear resistance and corrosion behavior were assessed using a Vickers microhardness tester, a ball-on-disk wear testing machine and the electrochemical measurement method, respectively. Microstructural studies show that the coatings possess a densely layered structure with the porosity less than 2.1%. The tribological behavior of the coatings examined under dry conditions shows that their relative wear resistance is five times higher than that of the substrate material. Both adhesive wear and abrasive wear contribute to the friction, but the former is the dominant wear mechanism of the metallic glass coatings. The coatings exhibit low passive current density and extremely wide passive region in 3.5% NaCl solution, thus indicating excellent corrosion resistance.
基金Project(2012M510271) supported by the China Postdoctoral Science FoundationProject(2012BAI18B05) supported by the Five-Year National Key Technology R&D Program during the 12th Five-year Plan of ChinaProject(2011AA030104) supported by the National High Technology Research and Development Program of China
文摘The NiA1 Cr(Mo) (Hf, Dy) hypoeutectic alloys were prepared by conventional casting and injection casting techniques respectively, and their microstructure and room temperature mechanical properties were investigated. The results reveal that with the addition of Hf and Dy, the Ni2AIHf Heusler phase and NisDy phase form along the NiAI/Cr(Mo) phase boundaries in intercellular region. By the injection casting method, some Ni2AIHf Heusler phase and NisDy phase transform into Hf and Dy solid solutions, respectively. Moreover, the microstructure of the alloy gets good optimization, which can be characterized by the fine interlamellar spacing, high proportion of eutectic cell area and homogeneously distributed fine Ni2AIHf, NisDy, Hf solid solution and Dy solid solutions. Compared with conventional-cast alloy, the room temperature mechanical properties of injection-cast alloy are improved obviously.
基金Project(2006CB605204) supported by the National Basic Research Program of China
文摘With the aim to improve the strength of Al-Zn-Mg-Cu alloy,the alloy billet containing Mn was produced by spray forming method,and the microstructural features were investigated using X-ray diffraction(XRD),optical microscopy(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM) and differential scanning calorimetry(DSC).The results show that the billet mainly consists of fine equiaxial grains of MgZn2 and Al6Mn with size ranging from 5 μm to 25 μm.Nano-scaled MgZn2 is dispersed in the as-sprayed alloy,primary Al6Mn particles are precipitated at grain boundaries with an average size of 5 μm.A few CuAl2,Al3Zr and eutectic are also found in as-sprayed Al alloy.The volume fraction of the porosity is about 12%.DSC result indicates that most of the solutes are precipitated during spray forming process,and no obviously thermal effects occur below 450 ℃.Both matrix grains and Al6Mn particles grow monotonously with the increase of annealing temperature,but the growth rate of Al6Mn particles is markedly lower than that of Al grains,and the matrix grains grow rapidly when the annealing temperature is above 375 ℃.
文摘TC6 titanium alloy samples are processed by laser shock peening (LSP). Then, some samples are vacu- um annealed at 623 K for 10 h for the study on the thermost.ablity of the nanostructure produced by LSP. The characteristics of the strengthened layer and nanostructure are studied by atomic force microscopy(AFM), scan- ning electron microscope (SEM), electron backscatter diffraction(EBSD), X-ray diffraction(XRD), and transmis- sion electron microscopy(TEM) appliances, meanwhile the enhanced microhardness is tested at cross section. AFM of the processed surface indicates that the deformation is approximately uniform, and LSP slightly increases the roughness. SEM and EBSD of the strengthened cross section show that a phases are compressed to strip- shaped, a proportion of a and ~ phases is shattered to smaller phases from surface to 200 ttm in depth. The sur- face XRD shows that although there is no new produced phase during LSP, the grain size refinement and the in- troduction of lattice micro-strains lead to the broadened peak. The TEM photographs and diffraction patterns in- dicate that the shock wave provides high strain rate deformation and leads to the formation of nanocrystal. Com- pared with the samples before annealing, the dislocation density is lower and the grain-boundary is more distinct in the annealed samples, but the nanocrystal size does not grow bigger after annealing. The microhardness measurement indicates that LSP improves the microhardness of TC6 for about 12.2% on the surface, and the layer affected by LSP is about 500/~m in depth. The microhardness after annealing is 10 HVo.5 lower, but the affected depth does not change. The thermostable study shows that the strengthened layer of TC6 processed by LSP is stable at 623 K. The strengthened thermostable layer can significantly improve the fatigue resistance, wear resis- tance and stress corrosion resistance of the titanium alloy. The study results break the USA standard AMS2546 that titanium parts after LSP are subjected in subsequent processing within 589 K.
文摘The airflow in the reed groove of the air jet loom for the weft insertion includes the jet stream from the relay nozzle, the back leak stream from the reed, and the diffusion stream from the open side. The air velocity in the reed groove can be measured to analyze the influence of process parameters during the weft insertion. The relation between the air velocity and the relay nozzle distance, the jet angle or the supply pressure of the relay nozzle can be studied. In this paper, the pitot tube is applied to measure the air velocity in reed groove by the instrument designed. And the results indicate that the air velocity fluctuation in the reed groove is strong, and can drop from 150 m·s-1 to 80 m·s-1 drastically.
基金Projects(51422507,51379168)supported by the National Natural Science Foundation of China
文摘A new kind of multi-dimensional WC-10Co4Cr coating which is composed of nano,submicron,micron WC grains and CoCr alloy,was developed by high velocity oxy-fuel(HVOF)spraying.Porosity,microhardness,fracture toughness and cavitation erosion resistance of the multi-dimensional coating were investigated in comparison with the bimodal and nanostructured WC?10Co4Cr coatings.Moreover,the cavitation erosion behavior and mechanism of the multi-dimensional coating were explored.Results show that HVOF sprayed multi-dimensional WC-10Co4Cr coating possesses low porosity(≤0.32%)and high fracture toughness without obvious nano WC decarburization during spraying.Furthermore,it is discovered that the multi-dimensional WC-10Co4Cr coating exhibits the best cavitation erosion resistance which is enhanced by approximately 28%and 34%,respectively,compared with the nanostructured and bimodal coatings in fresh water.The superior cavitation resistance of multi-dimensional WC-10Co4Cr coating may originate from the unique micro?nano structure and excellent properties,which can effectively obstruct the formation and propagation of cavitation erosion cracks.
文摘The watar jet impulse is brought forward to study the traction force of the water jet to the flying weft in water-jet looms. The distribution of the water jet impulse in the shed is tested by a sensor, and the influence of water jet parameters on the water jet impulse is analyzed.
文摘In order to study the propulsive force on the water-jet to the flying weft in water-jet looms, a dynamic model has been established. Based on the analysis and example testing, an experiential formula of the propulsive force of the water-jet to the flying weft is obtained for the first time. The formula will profit the further research of the water-jet weft insertion and the production of textile.
文摘This article deals with the energy efficiency of textile weaving machines. A method based on exergy balances has been developed at the Institute for Textile Technology RWTH Aachen University (ITA), Aachen, Germany in order to improve energy efficiency textile machines. The relay nozzles of the air-jet weaving technology need up to 80% of the energy of the weaving machine. At ITA, a new nozzle concept was developed. The developed geometry is a so called High-Volume-Low-Pressure nozzle (HVLP nozzle), based on convergent nozzle aerodynamic theory. With this concept, energy savings up to 30% are possible.
文摘In the water jet looms, the distribution of the speed of water jet at the axis of the shed and its regularity are obtained by the Laser Doppler Tester. Based on the above, the water jet system is analyzed and the main effective approaches to increase the filling insertion rate and to widen the reed space of the loom are pointed out.
基金Project(2017JJ2073) supported by the Natural Science Foundation of Hunan Province,ChinaProject(15B063) supported by the Youth Research Foundation of Education Bureau of Hunan Province,China
文摘The extrusion preform of the spray-formed5A12Al alloy was hot rolled using high reduction rolling technology.By means of transmission electron microscopy(TEM),electron backscatter diffraction(EBSD)and energy dispersive spectroscopy(EDS),the microstructure evolution was studied and the strengthening and toughening mechanism was thereby proposed.The results indicate that discontinuous and continuous dynamic recrystallization occurred during the hot rolling deformation of the spray-formed5A12Al alloy.The grain size was significantly refined and the micro-scale grains formed.Partial dynamic recrystallization leads to a significant increase of dislocation density and cellular structure.The Mg atoms were distributed in the Al matrix mainly in the presence of solid solution rather than the formation of precipitate.High solid solution of Mg atoms not only hindered the dislocation motion and increased the density of dislocation,but also exhibited a remarkable solid solution strengthening effect,which contributes to the high strength and high toughness of the as-rolled sheets.The tensile strength and elongation of spray formed5A12Al alloy at room temperature after3passes hot rolling were622MPa and20%,respectively.
文摘The objective of this research was to investigate the optimum condition for treatment of textile industrial wastewater from water jet loom machine by chemical coagulation and electrocoagulation methods. The variables of chemical coagulation method were type and amount of chemicals, pH and stirring rate. For electrocoagulation method, the variables were electrode materials, electric potential and contact time. It was found that the optimum condition of chemical coagulation method was 10% (w/w) of aqueous solution of aluminum sulphate 80 mL and 0.01% (w/w) of aqueous solution of coagulant aids, cationic polymer 32 mL per 4 L of wastewater at oH 8. The mixture solution was rapidly stirred with 120 rpm for 1 min and then slowly stirred with 20 rpm for 20 rain. The removal efficiency of turbidity, COD and oil content were 88.88%, 85.20% and 77.72%, respectively. For electrocoagulation method, the optimum condition was using aluminum electrode with 35 V and 150 min of contact time. The removal efficiency of turbidity, COD and oil content were 98.86%, 91.63% and 89.84%, respectively. It can be concluded from this study that the textile industrial wastewater treatment from water jet loom machine with electrocoagulation method is more efficient than that with chemical coagulation method.
基金New Century Excellent Talents of China ( NCET,No.040495)National Natural Science Foundation of China(NSFC, No.20474025)+1 种基金National Key Technology R&DProgram,China (No.2007BAE40B01)Innovative Research Team of Jiangnan University,China
文摘Without any preprocessing,polyester fabric has lower ability to hold on water and inks due to the smooth morphology of polyester fibers. Therefore, patterns directly printed with pigment inks have poor color yields and bleed easily. Pretreatments of polyester fabric were carried out with atmospheric air plasma under different experimental conditions. After plasma treatment the samples were printed with magenta pigment ink. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses indicated that the enhanced color performance was mainly contributed by not only the etching effect but also oxygen-containing polar groups induced onto fiber surfaces through plasma treatment. Thereby the surface modification of polyester fabrics using atmospheric-pressure air plasma offers a potential way to fabric pretreatment for pigment inkjet printing with the advantages of environmental friendly and energy saving over traditional pretreatment methods.
基金supported by CAPES, FINEP (FINEP/CTENERG: 01.09.0485.00)a FAPESP Project (2013/05987-8)a BPE grant awarded to C.R.M. Afonso (2015/19978-6)
文摘Recycled high-strength aluminum alloys have limited use as structural materials due to poor mechanical properties. Spray forming remelting followed by hot extrusion is a promising route for reprocessing 7 xxx alloys. The 7050 alloy machining chips were spray formed, hot extruded, rotary swaged and heat-treated in order to improve mechanical properties. Microstructures, tensile properties and fatigue strength results for a 2.7 mm-diameter recycled wire are presented. Secondary phases and precipitates were investigated by XRD, SEM, EBSD, TEM and DSC. As-swaged and heat-treated(solution and aging) conditions were evaluated. Mechanical properties of both conditions outperformed AA7050 aerospace specification. Substantial grain refinement resulted from the extensive plastic deformation imposed by rotary swaging. Refined micrometric and sub-micrometric Al grains, as well as coarse and fine intermetallic precipitates were observed. Subsequent solution treatment resulted in a homogeneous, recrystallized and equiaxed microstructure with grain size of 9 μm. Nanoscale GP(I) zones and η′ phase precipitates formed after aging at 120 ℃, imparting higher tensile(586 MPa) and fatigue(198 MPa) strengths.
文摘Analytical examination was made to ascertain the effect of the high pressure water flow on the fabric properties.Polyester/cotton blended cambric was spurted by high pressure water flow. Fabric properties such as handle,thickness, tensile strength , stiffness and air permeability after the water treatment were investigated.