A pipeline steel X80 with welded joint was subjected to surface mechanical attrition treatment (SMAT). After SMAT, a nanostructure surface layer with an average grain size of about 10 nm was formed in the treated sa...A pipeline steel X80 with welded joint was subjected to surface mechanical attrition treatment (SMAT). After SMAT, a nanostructure surface layer with an average grain size of about 10 nm was formed in the treated sample, and the fatigue limit of the welded joint was elevated by about 13% relative to the untreated joints. In the low and the high amplitude stress regimes, both fatigue strength and fatigue life were enhanced. Formation of the nanostructured surface layer played more important role in the enhanced fatigue behavior than that of residual stress induced by the SMAT.展开更多
Nano-structured layers are fabricated on the surface of 1.0C-1.5Cr steel by using the surface mechanical attrition treatment(SMAT)technology,and the microstructures of the surface nano-crystallization layers are chara...Nano-structured layers are fabricated on the surface of 1.0C-1.5Cr steel by using the surface mechanical attrition treatment(SMAT)technology,and the microstructures of the surface nano-crystallization layers are characterized by means of X-ray diffraction(XRD)and transmission electron microscopy(TEM).The friction and wear properties are also investigated by a UMT-2 friction and wear tester.Experimental research has indicated that the average diameter of nanocrystalline grains in the surface layer after being treated for 15 min is in the range of 10-20 nm,and ferrite and cementite grains can not be identified by their morphologies.The wear-resistance of the specimen treated for 15 min has been doubled,compared with that of the matrix due to the grain refinement to a nano-sized scale.The lowest friction coefficient is 0.27,which is for the specimen treated for 30 min,resulting from the dissolution of the cementite phase and the formation of a relative homogenous structure.The SMAT technique for enhancing the wear-resistance of the 1.0C-1.5Cr steel has an optimum processing time,which is in the range of 15-30 min.The dominant wear mechanism of the specimen treated for 15 min changes from adhesive wear into particle wear.展开更多
Single crystal silicon freestanding structures for tensile and fatigue testing were treated with KrF excimer laser to improve surface roughness and accordingly mechanical performance. Sample thickness was 5 μm. Local...Single crystal silicon freestanding structures for tensile and fatigue testing were treated with KrF excimer laser to improve surface roughness and accordingly mechanical performance. Sample thickness was 5 μm. Localized laser treatment was successful in eliminating the scallops developed during Bosch process and in reducing surface roughness. Harsh irradiation at laser energies up to 4 J/cm2 was only possible due to localized treatment without significant vibrations occurring on the freestanding samples that led to fracture in preliminary experiments at energies as low as 0.16 J/cm2. Finite element analysis was used to investigate the temperature distribution on the irradiated structures. Atomic force microscopy (AFM) and Raman spectroscopy were also used to assess surface roughness, crystallinity changes and surface stresses developing on surfaces subjected to perpendicular laser irradiation. At a high energy (3.2 J/cm2) the top surface showed a decrease of roughness compared to fabricated samples. Raman spectroscopy showed the dominance of crystalline silicon after laser irradiation. The effects of laser energy, number of展开更多
By means of surface mechanical attrition (SMA), a nanostructured surface layer was formed on a 0Cr18Ni9Ti austenite stainless steel plate. A strain-induced martensite transformation was observed during SMA treatment, ...By means of surface mechanical attrition (SMA), a nanostructured surface layer was formed on a 0Cr18Ni9Ti austenite stainless steel plate. A strain-induced martensite transformation was observed during SMA treatment, and a single magnetic martensite phase layer with thickness of about 30 μm was gotten. The grain growth and phase transformations in the nanocrystalline layer are investigated during heating. The grain growth exponent for nanocrystalline polycrystalline steel is estimated. The kinetics mechanism governing the grain growth in the nanocrystalline layer is discussed. The martensite in the surface layer is quite stable and the temperature at which the reverse transformation of martensite to austenite starts during heating is about 500 ℃.展开更多
In the case of valuable cold-rolled Cu/Al clad plates,billet surface treatment before rolling is a significant process that can affect the bonding efficiency and quality.While the current studies primarily focus on th...In the case of valuable cold-rolled Cu/Al clad plates,billet surface treatment before rolling is a significant process that can affect the bonding efficiency and quality.While the current studies primarily focus on the influence of rolling parameters,insufficient attention has been paid to surface treatment.In this study,the effects of mechanical surface treatment on the bonding mechanism and bonding properties of cold-rolled Cu/Al clad plates were investigated.The results showed that different mechanical surface treatments have significant effects on the surface morphology,roughness,and residual stress.In addition,the effect of surface mechanical treatment on bonding quality was also observed to be critical.When the grinding direction was consistent with the rolling direction(RD),the bonding quality of the Cu/Al clad plates was significantly improved.After surface treatment along the RD for 20 s,the Cu/Al clad plates showed the highest shear strength(78 MPa),approximately four times as high as that of the unpolished samples.Simultaneously,the peel strength of this process was also significantly higher than that achieved via the other processes.Finally,on the basis of the surface morphology,roughness,and residual stress,the effect of surface treatment on the bonding mechanism and bonding properties of Cu/Al clad plates was analyzed.This study proposes a deeper understanding of the bonding behavior and bonding mechanism for cold rolled clad plates processed via mechanical surface treatment.展开更多
A nanostructured surface layer can be formed in Ni metal treated by surface mechanical attrition (SMA). The microstructure was investigated by using optical microscope, X-ray diffractometer and transmission electron m...A nanostructured surface layer can be formed in Ni metal treated by surface mechanical attrition (SMA). The microstructure was investigated by using optical microscope, X-ray diffractometer and transmission electron microscope, respectively. Mechanical property measurements indicate that the yield strength of the surface layer raises significantly while the tensile strength somewhat changes and the elongation percentage reduces severely compared with that of the inside layer. Meanwhile, yield-drop-like phenomenon occurs in the surface layer after SMA treatment. In order to compare the mechanical behavior of nanostructured materials with two phases, Fe-30Ni nanostructured alloy was also investigated.展开更多
In order to lower the boriding temperature of hot work steel H13, method of surface mechanical attrition treatment (SMAT), which can make the grain size of the surface reach nano-scale, was used before pack boriding...In order to lower the boriding temperature of hot work steel H13, method of surface mechanical attrition treatment (SMAT), which can make the grain size of the surface reach nano-scale, was used before pack boriding. The growth of the boride layer was studied in a function of boriding temperature and time. By TEM (transmission electron microscopy), SEM (scanning electron microscopy), XRD (x-ray diffraction) and microhardness tests, the grain size, thermal stability of the nano-structured (NS) surface and the thickness,appearance, phases of the surface boride layer were studied. Kinetic of boriding was compared between untreated samples and treated samples. Results showed that after SMAT, the boride layer was thicker and the hardness gradient was smoother. Furthermore, after boriding at a low temperature of 700℃ for 8 h, a boride layer of about 5 μm formed on the NS surface. This layer was toothlike and wedged into the substrate, which made the surface layer combine well with the substrate. The phase of the boride layer was Fe2B. Research on boriding kinetics indicated that the activation energy was decreased for the treated samples.展开更多
Cold plasma technology was used to treat the surface of carbon fibers braided by PET in this paper and SEM was used to analyze the fracture microstructure of composite interlaminar shear stress (ILSS). The result show...Cold plasma technology was used to treat the surface of carbon fibers braided by PET in this paper and SEM was used to analyze the fracture microstructure of composite interlaminar shear stress (ILSS). The result shows that the surface polarity of carbon fibers was modified by cold plasma treatment, which increases the impregnation of PET braided carbon fibers during the process of resin flowing, improves the interfacial properties of RTM composites, and therefore enhances the mechanical properties of the KTM composites.展开更多
Nano-SiO2/polypropylene composite was prepared by melt-blending process. The nano-SiO2 particles were organized by wet process surface treatment with silane coupling agent KH-570. The effect of mass fraction of nano-S...Nano-SiO2/polypropylene composite was prepared by melt-blending process. The nano-SiO2 particles were organized by wet process surface treatment with silane coupling agent KH-570. The effect of mass fraction of nano-SiO2 particles and dosage of KH-570 on the toughening and strengthening of PP matrix were investigated based on the fractography of impact notch and the analysis of crystal structure by X-ray and dispersive structure of nano-SiO2 by TEM. Results show that the impact and flexural strength and modulus of the composite are improved obviously with low loading of nano-SiO2 (3 wt%-5 wt%), and the izod impact strength of PP increases twice with 4 wt% nano-SiO2. The nano-SiO2 particles treated can disperse into the matrix resin, which has evident heterogeneous nucleation effects on the crystallization of PP. The optimal toughening and strengthening effects of PP matrix can be obtained when the content of nano-SiO2 and KH-570 are 4 wt% and 3 wt%, respectively.展开更多
Sapphire single crystals are widely used in many areas because of the special physic properties and important application value. As an important substrate material, stringent surface quality requirements, i.e. surface...Sapphire single crystals are widely used in many areas because of the special physic properties and important application value. As an important substrate material, stringent surface quality requirements, i.e. surface finish and flatness, are required. The use of CMP technique can produce high quality surface finishes at low cost and with fast material removal rates. The sapphire substrate surface is treated by using CMP method. According to sapphire substrate and its product properties, SiO2 sol is chosen as abrasive. The particle size is 15-25 nm and the concentration is 40%. According to the experiment results, pH value is 10.5-11.5. After polishing and cleaning the sapphire surface, the surface roughness was measured by using AFM method and the lowest value of Ra 0.1 nm was obtained. From the results, it can be seen that using such method, the optimal sapphire surface can be gotten, which is advantageous for epitaxial growth and device making-up.展开更多
Natural fiber-reinforced hybrid composites can be a better replacement for plastic composites since these plastic composites pose a serious threat to the environment.The aim of this study is to analyze the effect of s...Natural fiber-reinforced hybrid composites can be a better replacement for plastic composites since these plastic composites pose a serious threat to the environment.The aim of this study is to analyze the effect of surface modification of the natural fibers on the mechanical,thermal,hygrothermal,and water absorption behaviors of flax,sisal,and glass fiber-reinforced epoxy hybrid composites.The mechanical properties of alkaline treated sisal and flax fibers were found to increase considerably.Tensile,flexural and impact strength of glass/flax-fiber-reinforced hybrid samples improved by 58%,36%,and 51%,respectively,after surface alkaline treatment.In addition,the hygrothermal analysis and water absorption capacity are studied and also the Interfacial bonding properties were analyzed using Scanning Electron Microscopic images.The thermal analysis using thermogravimetric analyzer reveals that the decomposition temperature for hybrid fiber reinforced composites are between 306 and 312℃.In conclusion,surface treatment improves the performance of natural fiber in hybrid fiber-reinforced composites,particularly flax fiber.展开更多
Mg-Cu alloys are promising antibacterial implant materials.However,their clinical applications have been impeded by their high initial biodegradation rate,which can be alleviated using nanotechnology by for example su...Mg-Cu alloys are promising antibacterial implant materials.However,their clinical applications have been impeded by their high initial biodegradation rate,which can be alleviated using nanotechnology by for example surface nanomodification to obtain a gradient nanostructured surface layer.The present work(i)produced a gradient nanostructured surface layer with a∼500µm thickness on a Mg-0.2 Cu alloy by a surface mechanical grinding treatment(SMGT),and(ii)studied the biodegradation behavior in Hank's solution.The initial biodegradation rate of the SMGTed samples was significantly lower than that of the unSMGTed original counterparts,which was attributed to the surface nanocrystallization,and the fragmentation and re-dissolution of Mg_(2)Cu particles in the surface of the SMGTed Mg-0.2 Cu alloy.Furthermore,the SMGTed Mg-0.2 Cu alloy had good antibacterial efficacy.This work creatively used SMGT technology to produce a high-performance Mg alloy implant material.展开更多
This study aims for development of highly filled jute fiber reinforced composites that contains jute fiber over fiber weight fraction 60%,and jute fiber reinforced composite was fabricated by the hot-pressing method.T...This study aims for development of highly filled jute fiber reinforced composites that contains jute fiber over fiber weight fraction 60%,and jute fiber reinforced composite was fabricated by the hot-pressing method.The molding temperature was changed from 175°C to 230°C,to investigate the effect of molding temperature on the mechanical properties of jute fiber reinforced composites.The effect of surface treatment of jute fiber on the mechanical properties of jute fiber reinforced composites was also investigated.As a result,the jute fiber reinforced composites using surface treated fiber has low porosity,and the jute fiber reinforced composite having low porosity has high flexural strength and modulus.The jute fiber reinforced composite using acetone treated fiber molded at 200°C has the maximum flexural strength and modulus.展开更多
The nanocrystalline microstructure of the surface of 316 stainless steel (316SS) induced by surface mechanical attrition treatment (SMAT) was determined by X-ray diffraction (XRD) and scanning electron microsco...The nanocrystalline microstructure of the surface of 316 stainless steel (316SS) induced by surface mechanical attrition treatment (SMAT) was determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The technique of hydrogen embrittlement was first used to obtain the information of the brittleness cleavage plane. The effects of SMAT and the following annealing process on the corrosion behavior of 316SS were investiga- ted by potentiodynamic polarization curves and potentiostatic critical pitting temperature measurements. The results demonstrated that the nanoerystalline layer with an average grain size of 19 nm was produced. However, there were lots of cracks on the surface, which led to the degradation in the corrosion resistance of 316SS after SMAT. Never- theless, after annealing treatment, the corrosion resistance of the nanocrystalline surface had been improved greatly. The higher the annealing temperature, the better was the corrosion resistance.展开更多
基金supported by the CNPC (China National Petroleum Corporation) Innovation Foundation under grant No.07E1015
文摘A pipeline steel X80 with welded joint was subjected to surface mechanical attrition treatment (SMAT). After SMAT, a nanostructure surface layer with an average grain size of about 10 nm was formed in the treated sample, and the fatigue limit of the welded joint was elevated by about 13% relative to the untreated joints. In the low and the high amplitude stress regimes, both fatigue strength and fatigue life were enhanced. Formation of the nanostructured surface layer played more important role in the enhanced fatigue behavior than that of residual stress induced by the SMAT.
基金supported by the National High-Tech.R&D Program of China(the National 863 plans projects,Grant No.2007AA03Z352)
文摘Nano-structured layers are fabricated on the surface of 1.0C-1.5Cr steel by using the surface mechanical attrition treatment(SMAT)technology,and the microstructures of the surface nano-crystallization layers are characterized by means of X-ray diffraction(XRD)and transmission electron microscopy(TEM).The friction and wear properties are also investigated by a UMT-2 friction and wear tester.Experimental research has indicated that the average diameter of nanocrystalline grains in the surface layer after being treated for 15 min is in the range of 10-20 nm,and ferrite and cementite grains can not be identified by their morphologies.The wear-resistance of the specimen treated for 15 min has been doubled,compared with that of the matrix due to the grain refinement to a nano-sized scale.The lowest friction coefficient is 0.27,which is for the specimen treated for 30 min,resulting from the dissolution of the cementite phase and the formation of a relative homogenous structure.The SMAT technique for enhancing the wear-resistance of the 1.0C-1.5Cr steel has an optimum processing time,which is in the range of 15-30 min.The dominant wear mechanism of the specimen treated for 15 min changes from adhesive wear into particle wear.
基金Financial support from the Chinese Academy of Sciences and National Natural Science Foundation of China (No.50071061)Conseil Regional de Champagne Ardenne France is appreciated.
文摘Single crystal silicon freestanding structures for tensile and fatigue testing were treated with KrF excimer laser to improve surface roughness and accordingly mechanical performance. Sample thickness was 5 μm. Localized laser treatment was successful in eliminating the scallops developed during Bosch process and in reducing surface roughness. Harsh irradiation at laser energies up to 4 J/cm2 was only possible due to localized treatment without significant vibrations occurring on the freestanding samples that led to fracture in preliminary experiments at energies as low as 0.16 J/cm2. Finite element analysis was used to investigate the temperature distribution on the irradiated structures. Atomic force microscopy (AFM) and Raman spectroscopy were also used to assess surface roughness, crystallinity changes and surface stresses developing on surfaces subjected to perpendicular laser irradiation. At a high energy (3.2 J/cm2) the top surface showed a decrease of roughness compared to fabricated samples. Raman spectroscopy showed the dominance of crystalline silicon after laser irradiation. The effects of laser energy, number of
文摘By means of surface mechanical attrition (SMA), a nanostructured surface layer was formed on a 0Cr18Ni9Ti austenite stainless steel plate. A strain-induced martensite transformation was observed during SMA treatment, and a single magnetic martensite phase layer with thickness of about 30 μm was gotten. The grain growth and phase transformations in the nanocrystalline layer are investigated during heating. The grain growth exponent for nanocrystalline polycrystalline steel is estimated. The kinetics mechanism governing the grain growth in the nanocrystalline layer is discussed. The martensite in the surface layer is quite stable and the temperature at which the reverse transformation of martensite to austenite starts during heating is about 500 ℃.
基金Supported by Major Program of National Natural Science Foundation of China(Grant No.U1710254)National Natural Science Foundation of China(Grant Nos.51904205,51804215)+3 种基金Shanxi Provincial Science and Technology Major Projects of China(Grant No.20181101008)Shanxi Provincial Natural Science Foundation of China(Grant No.201801D221221)China Postdoctoral Science Foundation(Grant No.2018M641681)Taiyuan Municipal Science and Technology Major Projects of China(Grant No.170203).
文摘In the case of valuable cold-rolled Cu/Al clad plates,billet surface treatment before rolling is a significant process that can affect the bonding efficiency and quality.While the current studies primarily focus on the influence of rolling parameters,insufficient attention has been paid to surface treatment.In this study,the effects of mechanical surface treatment on the bonding mechanism and bonding properties of cold-rolled Cu/Al clad plates were investigated.The results showed that different mechanical surface treatments have significant effects on the surface morphology,roughness,and residual stress.In addition,the effect of surface mechanical treatment on bonding quality was also observed to be critical.When the grinding direction was consistent with the rolling direction(RD),the bonding quality of the Cu/Al clad plates was significantly improved.After surface treatment along the RD for 20 s,the Cu/Al clad plates showed the highest shear strength(78 MPa),approximately four times as high as that of the unpolished samples.Simultaneously,the peel strength of this process was also significantly higher than that achieved via the other processes.Finally,on the basis of the surface morphology,roughness,and residual stress,the effect of surface treatment on the bonding mechanism and bonding properties of Cu/Al clad plates was analyzed.This study proposes a deeper understanding of the bonding behavior and bonding mechanism for cold rolled clad plates processed via mechanical surface treatment.
基金supported financially by the Science and Technology Foundation of Shanghai under Grant No.0210nm017.
文摘A nanostructured surface layer can be formed in Ni metal treated by surface mechanical attrition (SMA). The microstructure was investigated by using optical microscope, X-ray diffractometer and transmission electron microscope, respectively. Mechanical property measurements indicate that the yield strength of the surface layer raises significantly while the tensile strength somewhat changes and the elongation percentage reduces severely compared with that of the inside layer. Meanwhile, yield-drop-like phenomenon occurs in the surface layer after SMA treatment. In order to compare the mechanical behavior of nanostructured materials with two phases, Fe-30Ni nanostructured alloy was also investigated.
文摘In order to lower the boriding temperature of hot work steel H13, method of surface mechanical attrition treatment (SMAT), which can make the grain size of the surface reach nano-scale, was used before pack boriding. The growth of the boride layer was studied in a function of boriding temperature and time. By TEM (transmission electron microscopy), SEM (scanning electron microscopy), XRD (x-ray diffraction) and microhardness tests, the grain size, thermal stability of the nano-structured (NS) surface and the thickness,appearance, phases of the surface boride layer were studied. Kinetic of boriding was compared between untreated samples and treated samples. Results showed that after SMAT, the boride layer was thicker and the hardness gradient was smoother. Furthermore, after boriding at a low temperature of 700℃ for 8 h, a boride layer of about 5 μm formed on the NS surface. This layer was toothlike and wedged into the substrate, which made the surface layer combine well with the substrate. The phase of the boride layer was Fe2B. Research on boriding kinetics indicated that the activation energy was decreased for the treated samples.
文摘Cold plasma technology was used to treat the surface of carbon fibers braided by PET in this paper and SEM was used to analyze the fracture microstructure of composite interlaminar shear stress (ILSS). The result shows that the surface polarity of carbon fibers was modified by cold plasma treatment, which increases the impregnation of PET braided carbon fibers during the process of resin flowing, improves the interfacial properties of RTM composites, and therefore enhances the mechanical properties of the KTM composites.
基金Funded by the Commission of Science Technology and Industry for National Defense(No.93013)
文摘Nano-SiO2/polypropylene composite was prepared by melt-blending process. The nano-SiO2 particles were organized by wet process surface treatment with silane coupling agent KH-570. The effect of mass fraction of nano-SiO2 particles and dosage of KH-570 on the toughening and strengthening of PP matrix were investigated based on the fractography of impact notch and the analysis of crystal structure by X-ray and dispersive structure of nano-SiO2 by TEM. Results show that the impact and flexural strength and modulus of the composite are improved obviously with low loading of nano-SiO2 (3 wt%-5 wt%), and the izod impact strength of PP increases twice with 4 wt% nano-SiO2. The nano-SiO2 particles treated can disperse into the matrix resin, which has evident heterogeneous nucleation effects on the crystallization of PP. The optimal toughening and strengthening effects of PP matrix can be obtained when the content of nano-SiO2 and KH-570 are 4 wt% and 3 wt%, respectively.
基金Project(043801211) supported by the Tianjin Natural Science Foundation Project(20050080007) supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘Sapphire single crystals are widely used in many areas because of the special physic properties and important application value. As an important substrate material, stringent surface quality requirements, i.e. surface finish and flatness, are required. The use of CMP technique can produce high quality surface finishes at low cost and with fast material removal rates. The sapphire substrate surface is treated by using CMP method. According to sapphire substrate and its product properties, SiO2 sol is chosen as abrasive. The particle size is 15-25 nm and the concentration is 40%. According to the experiment results, pH value is 10.5-11.5. After polishing and cleaning the sapphire surface, the surface roughness was measured by using AFM method and the lowest value of Ra 0.1 nm was obtained. From the results, it can be seen that using such method, the optimal sapphire surface can be gotten, which is advantageous for epitaxial growth and device making-up.
文摘Natural fiber-reinforced hybrid composites can be a better replacement for plastic composites since these plastic composites pose a serious threat to the environment.The aim of this study is to analyze the effect of surface modification of the natural fibers on the mechanical,thermal,hygrothermal,and water absorption behaviors of flax,sisal,and glass fiber-reinforced epoxy hybrid composites.The mechanical properties of alkaline treated sisal and flax fibers were found to increase considerably.Tensile,flexural and impact strength of glass/flax-fiber-reinforced hybrid samples improved by 58%,36%,and 51%,respectively,after surface alkaline treatment.In addition,the hygrothermal analysis and water absorption capacity are studied and also the Interfacial bonding properties were analyzed using Scanning Electron Microscopic images.The thermal analysis using thermogravimetric analyzer reveals that the decomposition temperature for hybrid fiber reinforced composites are between 306 and 312℃.In conclusion,surface treatment improves the performance of natural fiber in hybrid fiber-reinforced composites,particularly flax fiber.
基金Financially supported by Natural Science Foundation of China(No.51874368).
文摘Mg-Cu alloys are promising antibacterial implant materials.However,their clinical applications have been impeded by their high initial biodegradation rate,which can be alleviated using nanotechnology by for example surface nanomodification to obtain a gradient nanostructured surface layer.The present work(i)produced a gradient nanostructured surface layer with a∼500µm thickness on a Mg-0.2 Cu alloy by a surface mechanical grinding treatment(SMGT),and(ii)studied the biodegradation behavior in Hank's solution.The initial biodegradation rate of the SMGTed samples was significantly lower than that of the unSMGTed original counterparts,which was attributed to the surface nanocrystallization,and the fragmentation and re-dissolution of Mg_(2)Cu particles in the surface of the SMGTed Mg-0.2 Cu alloy.Furthermore,the SMGTed Mg-0.2 Cu alloy had good antibacterial efficacy.This work creatively used SMGT technology to produce a high-performance Mg alloy implant material.
文摘This study aims for development of highly filled jute fiber reinforced composites that contains jute fiber over fiber weight fraction 60%,and jute fiber reinforced composite was fabricated by the hot-pressing method.The molding temperature was changed from 175°C to 230°C,to investigate the effect of molding temperature on the mechanical properties of jute fiber reinforced composites.The effect of surface treatment of jute fiber on the mechanical properties of jute fiber reinforced composites was also investigated.As a result,the jute fiber reinforced composites using surface treated fiber has low porosity,and the jute fiber reinforced composite having low porosity has high flexural strength and modulus.The jute fiber reinforced composite using acetone treated fiber molded at 200°C has the maximum flexural strength and modulus.
基金Item Sponsored by National Natural Science Foundation of China (50571027)
文摘The nanocrystalline microstructure of the surface of 316 stainless steel (316SS) induced by surface mechanical attrition treatment (SMAT) was determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The technique of hydrogen embrittlement was first used to obtain the information of the brittleness cleavage plane. The effects of SMAT and the following annealing process on the corrosion behavior of 316SS were investiga- ted by potentiodynamic polarization curves and potentiostatic critical pitting temperature measurements. The results demonstrated that the nanoerystalline layer with an average grain size of 19 nm was produced. However, there were lots of cracks on the surface, which led to the degradation in the corrosion resistance of 316SS after SMAT. Never- theless, after annealing treatment, the corrosion resistance of the nanocrystalline surface had been improved greatly. The higher the annealing temperature, the better was the corrosion resistance.