bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Element V on the Microstructure and Mechanical Properties of DZ417G Superalloy
Authors: Zhong Zhao Xu , Yu Xing Fu , Huang Ai Hua , Wang Yu Fei , Man Yan Lin , Cui Shu Sen
Published: April 2014

The effect of V content on the mechanical properties and microstructure of DZ417G alloy was studied in the present investigation. DZ417G alloy with different element V contents was smelted , then tested the mechanical properties and observed microstructure. The results show that with the increase of element V content, the morphology of rod type M23C6 carbides turned into block-type MC carbides, the size of carbides became bigger, and the amount of carbides decrased, but the dispersion degree of carbide in the matrix was increased. The alloy tensile strength and plastic properties were increased at high temperature with the increment of V content. There were finer dimple structures on the tensile rupture fracture surface of the alloy with high element V than the alloy with low element V under the high temperature conditions. The results of creep rupture life tests show that with increasing V content the creep rupture life increased at the test condition of 760 °C, 725MPa. The creep rupture life is 90h of the alloy with 0.62% V element content, and the creep rupture life increased to more than 245h when the element V content increased to 0.96%.
Composition and Mechanical Property of DD6 Superalloy Revert
Authors: Wu Qing Hui , Zhang Jian , Luo Yu Shi
Published: April 2014

DD6 superalloy revert ingot was smelt in an industrialized vacuum induction furnace,Inclusions quantity was tested by electron beam buttons. Purification effect, compositions, mechanical property and cast-ability of purified revert and normal virgin alloy was studied. The results show that the quantity of the inclusions of revert material was slightly higher than one of the normal virgin,and rupture life under 980°C/250MPa and 1100°C/130MPa was slightly higher, and the similar effect was also shown for the compositions and the tensile properties under the temperatures of 760°C and 980°C, as well as cast-ability.
Hot Working Behavior of Casting Thermo-Span Alloy
Authors: Yu Lian Xu , Zhang Zhou Bo , Huang Lin Jie , Zhang Wei Hong , Xin Xin , Liu Fang , Qi Feng , Jia Dan , Sun Wen Ru
Published: April 2014

Thermo-Span alloy is an oxidation resistant, low thermal expansion superalloy with good mechanical properties at the service temperature. This paper investigated the hot working behavior of casting Thermo-Span alloy deformed at 900~1150°C, with strains of 20%, 40% and 60% at strain rates of 1 and 10 s-1. Dynamic recrystallization (DRX) grains were formed at 1110°C with a strain of 20%, at 1050°C with a strain of 40%. Increasing the deformation rate and strain can promote the DRX. However, when the strain exceeded 60% or the deformation temperature was above 1150°C with 40% strain, the surface cracks occurred, indicating that the alloy should be deformed in one heat no larger than 60%. By forging and rolling at 1050°C, Thermo-Span alloy with good surface quality and homogeneous grains was produced, and the tensile properties were still acceptable.
Effects of High Temperature Treatments on PPB’s in a P/M Superalloy
Authors: Tao Yu , Ja Jian , Zhao Jun Pu
Published: April 2014

FGH96 components of aircraft engines were produced by a processing route of hot isostatic pressing plus heat treatment (as-HIP). The prior particle boundaries (PPB’s) could be found in those articles in spite of the lower carbon content in the alloy. Attempts to eliminate or reduce PPB’s in as-HIP FGH96 alloy have been carried out by either increasing the HIP temperature from 1180oC to 1230oC or taking an appended annealing treatment at 1230oC. Based on experimental results, a thermodynamic analysis by using Jmat Pro has been conducted to understand the effects of high temperature treatments on PPB’s in FGH96 alloy. PPB’s found in as-HIP FGH96 alloy were mainly constituted by MC carbides enriched in Ti and Nb. The results of a thermodynamic analysis presented that carbides precipitated on TiN nucleus and grew up to form PPB’s. High temperature treatments, both increasing HIP temperature and taking a high temperature annealing treatment after HIP, could reduce the equilibrium amount of MC carbides and the surface segregation of Ti in powder particles, and turned the continuous precipitates into broken particles on PPB’s. Although the PPB’s could not be completely eliminated by high temperature treatments, an obvious improvement in rupture life of the material could be observed.
Study on Fracture Morphologies of Nickel Based P/M Superalloy
Authors: Hou Xue Qin , He Yu Huai , Jiang Tao
Published: April 2014

Fracture morphology analysis is an important way to understand material fracture process, find the reason of fracture and improve its performance. Nickel based powder metallurgy (P/M) superalloy is an important material which is widely used in the modern aeronautic and astronautic industry. In order to determine the fracture characteristic morpholgies and mechanisms of the P/M superalloy fractured at different conditions, the fracture surfaces of the high temperature low cycle fatigue,high cycle fatigue, high-low cycle complex fatigue, tension and creep specimens from the P/M superalloy were studied by scanning electron microscopy and stereo-microscopy. The mechanisms and influencing factors of high temperature fatigue crack initiation and propagation were emphatically analyzed, and creep and tension fracture mechanisms of the P/M superalloy were also discussed. The application of the fracture surface analysis for the fracture failure analysis of the P/M superalloy turbine disk were introduced finally.
Effect of Slow Cooling Treatment on Microstructure and Dynamic Recrystallizaiton of FGH96 Alloy
Authors: Feng Ye Fei , Zhou Xiao Ming , Zou Jin Wen , Tian Gao Feng , Wang Wu Xiang
Published: April 2014

The effect of slow cooling treatment (SCT) on the microstructure and dynamic recrystallization of FGH96 alloy was studied. The results show that the grains of FGH96 alloy after slow cooling rate treatment grow from 20μm~30μm to 30μm~40μm, and the distance between γ′ precipitates in FGH96 alloy becomes larger. This promotes the dynamic recrystallization in the process of hot extrusion and isothermal hot compression and decreases the flow stress effectively.
Effects of Cooling Rates after Solution Heat Treatment on the Creep Behavior of Directionally Solidified CM-247LC Superalloy
Authors: Chiou Mau Sheng , Yeh An Chou , Jian Sheng Rui , Kuo Chen Ming
Published: April 2014

In this study, three cooling rates, namely, Argon cooling, air cooling and furnace cooling after solution heat treatment of directionally solidified CM-247LC superalloy were proposed to explore the high temperature/low stress (982°C/200MPa) creep behavior. Standard heat treatment schemes of DS CM-247LC superalloy are solution treatment at 1260°C for 2 hour, then first aging at 1079°C for 4 hour and followed by second aging at 871°C for 20 hour. Results show that Argon cooling specimen provided the longest creep rupture life, which exceeds that of the air cooling specimen around 40 hour; whereas the creep rupture life of furnace cooling specimen was the shortest one of 100 hour, which is shorter than that of the air cooling specimen around 40 hour. Rupture strains of all three specimens were almost identical around 20%. Microstructural differences of gamma prime morphology were observed to explain the differences of creep rupture life.
Effect of Long-Term Aging on the Microstructures and Stress Rupture Properties of a Ni-Based Single Crystal Superalloy at 980°C
Authors: Xu Jian Wei , Cui Li Li , Wang Hai Wen
Published: April 2014

The effect of aging time at 980°C on the microstructures and mechanic properties for a single crystal Ni-based superalloy was investigated in this paper. The results showed that γ’ size distribution portrayed a low growth rate and maintained well cubic during aging for 0~1000h at 980°C. However, γ’ phase was gradually coarsened directionally during the aging for 1000~2500h at 980°C, indicating that the γ’ phase coarsening was controlled by diffusion during aging for 0~1000h at 980°C. In addition, the γ’ phase coarsening was also susceptible to the interface reaction during aging for 1000~2500h at 980°C. Furthermore the precipitated phase was analyzed, and the results showed that only slightly Topologically Close-Packed (TCP) phase was precipitated after aging for 1500h at 980°C which indicates that the microstructures of alloy were stable during aging for up to 1500 hours. At the same time, stress rupture life decreased rapidly for 0~250h, but basically kept constant value when aged for 250~1500h, then decreased rapidly again aging for 1500~2000h.
Design, Preparation and Microwave-Absorbing Properties of Sandwich-Structure Radar-Absorbing Materials Reinforced by Glass and SiC Fibres
Authors: Liu Hai Tao , Cheng Hai Feng
Published: April 2014

In order to broaden the absorbing bandwidth of radar-absorbing materials (RAMs), a type of sandwich-structure RAMs (SSRAMs) derived from a Salisbury absorber and comprising two dielectric layers and one resistive sheet was investigated. In this paper, the impedance characteristics of the SSRAMs were analysed and the mechanisms of broadening microwave-absorbing bandwidth were interpreted using a Smith chart. In order to realise the study’s SSRAMs, plain-woven glass fibre fabric and silicon carbide (SiC) fibre fabric with low electrical resistivity were employed as reinforcements of the dielectric layers and lossy layer, respectively. The microwave-absorbing properties of the SSRAMs were measured and compared with simulated results. The results showed that the experimental and simulated results were in good agreement, that the SSRAMs had better wideband microwave-absorbing properties and that the microwave-absorbing bandwidth at reflectivity below −10 dB can reach 11.6 GHz.
Effect of Ce Addition on Microstructure and Mechanical Properties of ZM21 Magnesium Alloys
Authors: Fan Shi Bo , Peng Jian , Zhou Ming , Cui Kai , Li Quan
Published: April 2014

In this paper, the effects of Ce addition on the microstructure and mechanical properties of the cast and extruded ZM21 magnesium alloy were investigated by OM, XRD, SEM and tensile test at room temperature. It was found that with increase of Ce content, the Mg-Ce and Mg-Zn phases which gather in dendritic gap as second phases increase gradually, and form a network structure finally, which becomes thicker due to serious segregation. Meanwhile, Most of Ce in the extruded ZM21 magnesium alloy is in the forms of second phases, and is broken and dispersed in the matrix alloy during the plastic deformation. With the increase of Ce content, the quantity of the second phase increases, and both the tensile strength and the elongation of ZM21 alloys decrease firstly and then increase. When the content of Ce is 0.57%, the elongation barely reaches the level of ZM21 magnesium alloy. After extrusion, both the tensile and yield strength have been greatly improved.
Effect of Milling Time on Microstructure of CNTs/Al5083 Composites Powder by High Energy Milling
Authors: Li Zheng , Cai Xiao Lan , Yi Feng , Yu Ming Jun , Hu Chui
Published: April 2014

The 2wt%CNTs/Al5083 composite powder was prepared by High Energy Milling, and the effect of the milling time on microstructure of the 2wt.%CNTs/Al5083 composite powder was investigated. The Microstructure was observed by SEM, TEM and XRD. The result showed that prolonging the milling time lead to the reduction of the Medium particle size D50. The best D50 was obtained at milling 2.5h with the particle size of 22.33μm. CNTs homogeneous embedded into the Al-matrix when the milling time was 2.5h. The average crystallite size of Al was 46.4nm after milling for 2.5h, and the average crystallite size of Al also increased as the recrystallization.
Effect of Graphite on the Friction and Wear Properties of Cu-Based Friction Materials
Authors: Wei Jing Dan , Chen Hua
Published: April 2014

Cu-based friction materials were prepared by powder metallurgy technology. The effect of the graphite on friction and wear properties of materials was investigated. The experimental results indicate that the wear rate of the materials increased with increasing speed. The wear rate of the materials with the graphite with the size of 300~600μm decreased with increasing graphite content, indicating that the graphite size of 300~600μm showed the good lubricating effect. The lubricating film made the friction coefficient decrease. The wear resistance of materials with 100~300μm graphite was degraded at high graphite content, and the graphite size of 100~300μm has bad effect on the strength of materials. The wear debris made the friction coefficient slightly increase with the increase of graphite content. The material with the graphite content of 10% and the graphite size of 300~600μm has the best friction and wear properties.
Porous AlN Ceramics Fabricated by Carbothermal Reduction
Authors: Lu Yuan , Li Jing Long , Yang Jian Feng , Li Peng
Published: April 2014

A new method for preparing porous AlN ceramics with high porosity had been developed by carbothermal reduction of die-pressed green bodies composed of alumina, carbon, sintering additives and AlN seeds. The influences of sintering additives and sintering temperature on the microstructure and mechanical properties of porous AlN ceramics were investigated. XRD analysis proved that complete formation of AlN phase except for minor of glass phase. SEM analysis showed that the resultant porous AlN ceramics occupied fine microstructure and a uniform pore structure. Porous AlN ceramics with a porosity of 41~66% and a strength of 2.7~ 51.8 MPa were obtained.
Influences of Heat Treatment on Microstructure and Wear Resistance of WCp/40CrNi2Mo Metal Matrix Composites
Authors: Yang Lin , Deng Li Qiang , Han Yang , Han Ya Ling
Published: April 2014

A metal matrix composite 40CrNi2Mo strengthened with nanoscale WC particulate was fabricated through conventional casting in this work. The microstructure, hardness and wear resistance of this material were studied. The diffusion annealing processing was conducted at 900°C for 6.5h, and the quenching process with oil at 880°C for 2h. The temper process was conducted at 180°C, 220°C, 260°C and 500°C for 2h. It was found that the WC particulates surrounding the Fe3C phase were distributed evenly within the matrix. The segregation was discovered in the cast and was eliminated through annealing at the cost of hardness. The quenching, annealing at 180°C for 2hrs plus air cooling induced the tempered martensite, some ferrite and few retained austenite. The microstructure changed into the tempered sorbite after tempering at higher temperatures. The amount of precipitated carbides increased with the tempering temperature, but the hardness decreased gradually. Diffusion tempering, treated at 880°C for 2h followed by oil quenching, annealing at 180°C for 2h plus air cooling can give rise to the best wear resistance, which equals to 124.5% of the material currently employed.
Impact of Peak Shock Stress on the Microstructure and Reloaded Mechanical Behavior of AZ31 Magnesium Alloy
Authors: Hao Min , Tan Cheng Wen , Wang Xu Dong , He Wei Wei , Yang Bin
Published: April 2014

Magnesium alloys can be utilized as potential aerospace materials due to their low density, high specific strength, good vibration and shock absorption ability. This paper deals with the mechanical behavior of hot-rolled AZ31 alloy that was shock-deformed to 2.3 and 3.3 GPa. The post shock microstructure and mechanical response have been determined via full one-dimensional recovery techniques. The microstructure of deformed sample was characterized by the transmission electron microscopy (TEM) and electron back scattered diffraction (EBSD) techniques. All the shock-deformed materials showed shock-strengthening effect that was greater at higher shock pressure. The reload yield stress of the shock-deformed 2.3 GPa sample was determined to be 238 MPa while 264 MPa for the sample which shock-deformed at 3.3 GPa. It was postulated that the shock-strengthening is ascribed to a greater dislocation density and the formation of deformation twins.
Microstructure and Texture Evolution of Cu–Nb Nano-Composite Wire during Heat-Treatment
Authors: Sun Ze Yuan , Yang Xiao Fang , Deng Li Ping , Liu Qing
Published: April 2014

In this study, the microstructure and texture evolution of Cu-Nb nanocomposite wirescontaining 854Nb fibers after heat treatment were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The resultsare shown as follows:(1)Nb had the phenomenon of edge spheroidization and thermal gullies after annealing at 400oC. While the Nbfilaments were broken,showing edge spheroidization andcylinderization, and formed discontinuous bamboo-like structureafter annealing at 700oC for 1h, and the phenomenon of bamboo-like structure, spheroidization andcylinderizationafter annealing at 700oC for 2hwas moreseriousthan thatfor1h. (2) Several texture components appeared in the Cu matrix before heat treatment, however, <111>fiber texture component dominated after annealing at 400oC and 700oC. The textures of Nb filamentsseldomchanged during heat-treatment, exhibitinga major<110>fiber texture.
Influence of Deformation on Precipitation Behavior of 2024Al Alloy
Authors: He Shuan Xi , Wang Xi , Ma Bo Ran , Shi Yue , Zhang Wan Xin , Zhu Ming , Jiang Long Tao , Wu Gaohui
Published: April 2014

In the present work, 2024Al alloy was rolled before solid solution, between solid solution and aging, and after aging treatments. Precipitation sequence in 2024 Al has not been altered by the rolling treatment. However, peak aging temperature of S’ phase was decreased from 264 to 254 oC, implying that the process of S’precipitation was accelerated by the deformation. After thermo-mechanical treatments, precipitates werefiner dispersed, and finest precipitate distribution was observed after treatment III (rolling between solid solution and aging), while precipitate size was all smaller than 240nm and more than 95% precipitates was smaller than 200nm. The highest dislocation density was found in 2024Al alloy after treatment III since the dislocations generated during deformation was slightly decreased during following low temperature aging treatment. Therefore, in order to improve the mechanical properties, it is suggested that the rolling treatment should be performed between solid solution and aging treatment.
Microstructure and Mechanical Properties of As-Rolled Mg-Zn-Gd-Ca-Mn Sheets
Authors: Dongye Sheng Shuan , Yan Hong , Du Xing Hao , Chen Rong Shi
Published: April 2014

The Mg-(4,6)Zn-1Ca-1RE-0.5Mn magnesium alloy sheets were processed by hot rolling, and the effect of Zn concentration on the microstructure and mechanical properties was investigated using OM,SEM and XRD technique. The Mg-4Zn-1Ca-1RE-0.5Mn sheet exhibits excellent tensile properties at ambient temperature with ultimate tensile strength of 332MPa and elongation to failure of 4.5%. The notable mechanical properties were attributed to fine DRX grains and large deformed grains with intense basal texture.
Microstructural Evolution of Friction Stir Treated WE43 Alloy
Authors: Wang Xu Dong , Li Jiong Li , Lu Zheng , Zhang Xian Feng , Ma Zhi Feng , Sun Gang
Published: April 2014

Mg-Y-Nd (WE43) plate in 3mm thickness was friction stir welded (FSW) under a tool rotation rate of 800rpm and a traverse speed of 100 mm/min. The super plastic deformation structure was obtained in as-FSWed WE43 alloy. Coarse equiaxed recrystallized microstructure in extruded WE43 alloy with the average grain size of over 50μm changed into fine equiaxed recrystallized grains with the average grain size of under 5μm in the FSW core zone. The formation and evolution of hardening precipitates in WE43 alloy during ageing at 210oC is characterized by transmission electron microscopy (TEM) and high resolution electron microscopy (HREM) observations. It was indicated that the microstructure of as-FSWed WE43 always contain β’’ phase even without heat treatment. The hardening is mainly associated with the β’’→β’ transformation.
Fabrication and Characterization of Integrated Ultrahigh-Density Pt Nanowire Arrays within the AAO Template
Authors: Yang Wei , Cui Chun Xiang , Liu Qiao Zhi , Sun Ji Bing
Published: April 2014

The parallel Pt nanowires with highly ordered array and the length more than a dozen micrometers were prepared by the direct current electro-deposition in porous anodic aluminum oxide (AAO) templates. The deposition was performed in a aqueous solution of the Pt (NO2)2(NH3)2composite electrolyte. The images and structure of Pt nanowire arrays were obtained by field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM), respectively. Selected area electron diffraction (SAED) are employed to study the crystalline morphology of Pt nanowire arrays. The relationship between the nanowires length and electro-deposition time was discussed. Their growth speed is about 0.5μm/h. The TEM micrographs show that these nanowires have uniform diameter of approximate 55nm. SAED pattern reveals that the Pt nanowire has a polycrystalline structure.
Anti-Corrosive Epoxy Primer Modified with Nano Particles
Authors: Zhang Yu Zhong , Li Jing , Liu Tian Qi , Guan Zhen Wei , Wang Yan
Published: April 2014

An anti-corrosive primer was prepared with the epoxy resin modified with nanoparticles as its main film-formers.The influences of the ingredients, including the selection and proportion of epoxy resin modified with nanoparticles, curing agent,functional pigments and additives were studied in the present investigation.The results of performance test show that the epoxy resin modified with nanoparticles can enhance adhesion and flexibility of the coatings. Compared with the epoxy resin before modification, the film adhesion of the epoxy resin after modification increased by 3 times and flexibility changed from 30cm to 80cm. The resistance of salt fog and humid tropical condition of the coating were both more than 3000h. Meanwhile the coating has excellent comprehensive properties.
Preparation and Characterization of Ethylene-Octene Copolymer/Modified Nanosilica Composites by Radiation Processing
Authors: Zhang Si Deng , Wang Ren Lin , Wang Shi Chao , Zhou Zhe , Sun Bin , Zhu Mei Fang
Published: April 2014

Modified nanosilica (M-SiO2) by coupling agent (KH570, γ-MPS) with C=C bond reinforced ethylene-octene copolymer (POE) nanocomposites were prepared by melt blend, and then irradiated by γ-rays under nitrogen. The results of the crosslinking degree measurement revealed that the crosslinking degree of POE/modified nanosilica composites depended on the modified nanosilica particle size, content and the absorbed dose. Compared with the gel fraction of neat POE which is about 1.8%, the gel fraction of POE/15-M-SiO2-20 improves significantly to 34.2% at very low dose of 40kGy. Moreover, when nanosilica particle size become smaller, the sensitization effect is more obvious at a constant loading level. In comparison to the neat POE with a tensile strength of 22.6MPa, the tensile strength of POE/15-M-SiO2-10 nanocomposites increased to 29.1MPa with an absorbed dose of 100kGy, whereas their elongation at break were gradually reduced with an increasing absorbed dose. The improvement of gel content led to the enhancement of thermal deformation performance of POE/M-SiO2 nanocomposites attributed to the formation of crosslinked network between POE and modified nanosilica by radiation.
Improving Preferred Orientation and Mechanical Properties of the PAN-Based Carbon Fiber Precursors by Using Saturated Steam Stretching Process
Authors: Qiu Han , Chen Hui Fang
Published: April 2014

The saturated steam stretching process of the PAN-based carbon fiber precursors was studied. The orientation,crystallinity, and mechanical properties of the PAN fiber were analyzed by means of X-ray diffraction and XQ-2 tensile testing machine. The results demonstrated that the property of PAN fiber was very sensitive to the temperature, and the tensile strength and orientation degree increased with increasing temperature, which might be attributed to the changes of the super molecular structure. The stretching ratio also had great influence on the crystalline orientation of PAN fiber. Therefore, the temperature and stretching ratio for a certain fiber of the stretching process were matched and limited.
Raman Spectroscopy Studies on the Microstructure Evolution from Cellulose to Carbon Fiber
Authors: Ren Gui Zhi , Zang Yong Ju , Wang Ning , Deng Li Hui , Chen Cong Jie , Shi Yan Ni , Wu Qi Lin
Published: April 2014

Microstructure evolution of cellulose-based carbon fibers during the heat-treatment process of pyrolysis and carbonization was studied by Raman spectroscopy. The characteristic peaks of cellulose fibers were weakened after a dry process at 100°C and absolutely disappeared after the pyrolysis temperature reached 150°C. For intermediates obtained in the temperature of 150-1300°C, two characteristic Raman peaks appeared at ~1360cm-1 and ~1580cm-1, meaning a transition state structure of carbon hexagonal plane started to form. Parameters including ID1’/IG’, ID2’/IG’ and ID3’/IG’ of the intermediates treated in the temperature of 150-1300°C were compared. All the parameters firstly decreased with the increasing heat treatment temperature until a maximum at ~400°C,and then the parameters decreased until the structure turned into a carbon fiber structure at 1300°C.
Study on the Properties of Melamine Cyanurate Modified Polyamide 6 Nanocomposites with Different Dimensional Siliciferous Particles
Authors: Li Li Li , Wu Zhi Hao , Jiang Shuai Shuai , Wu Tian Ze , Lu Shou Yang , Sun Bin , Zhu Mei Fang
Published: April 2014

Different dimensional siliciferous particles including silica (0D), halloysite nanotubes (HNTs,1D) and montmorillonite (MMT,2D) were melt blending with certain amount of melamine cyanurate and polyamide 6(PA6) by a twin-screw extruder. Characterization of the PA6 composites has been investigated using scan electron microscopy (SEM), thermal gravimetric analyzer (TGA), universal testing machine and limiting oxygen index instrument. SEM images indicate that the nanoparticles were uniformly dispersed in the PA6 but there was some aggregation of MCA in the composites. The incorporation of silica exerted a negative effect on the flame retardancy of PA6/MCA composite, whereas adding HNTs and MMT lead to the improvements of LOI value of 30.4 and 30.9 respectively. TGA results show that PA6/MCA/silica, PA6/MCA/HNTs and PA6/MCA/OMMT exhibit two degradation stages. Higher Tmax1 and Tmax2 appeared comparing with PA6/MCA. Char residue of PA6/MCA/OMMT at 600°C were elevated most. HNTs and OMMT can increase the tensile strength and elongation of PA6/MCA by universal testing machine results, even higher than pure PA6, showing enhanced effects of these 1D and 2D fillers. These could enhance strength of the char and finally increase the flame retardancy of PA6.
Preparation and Properties of Recycled-Polyester Nanocomposite Fibers Synergistic Modified with Phosphorus Containing Flame-Retardant and α-Zirconium Phosphate
Authors: Wu Zhi Hao , Li Li Li , Jiang Shuai Shuai , Hu Ze Xu , Mao Yu Chen , Zhu Mei Fang
Published: April 2014

Recycled-polyester (RPET) was melt blended with the phosphorus-containing flame retardant (FRP) and α-zirconium phosphate (α-ZrP). The thermal properties of RPET/FRP/α-ZrP composites were analyzed. Modified RPET fibers were prepared through melt spinning of dried RPET nanocomposite chips. The mechanical properties and fire-retardant properties of RPET/FRP/α-ZrP fibers containing different α-ZrP contents were tested. The results show that the synergism of α-ZrP and FRP exerts a positive effect on the mechanical and the flame-retardant property of RPET, leading to nanocomposite fibers of 1.9cN/dtex and 31.6% limiting oxygen index (LOI) value.
Study of the Hydrophobic Properties of the Surface of an Enamel Material
Authors: Chen Li Yun , Fang Qian Qian , Jiang Wei Zhong , Liao Xiao Ping , Ye Jia Yi , Jin Hui Le
Published: April 2014

The hydrophobic properties of the surface of an enamel material are reported in this paper. By using a sol-gel method and with tetraethoxysilane as the precursor which is combined with dimethyldichlorosilane (DDS), the films composed of DDS-SiO2nanoparticle composite materials were prepared on an enamel surface, with the droplet’s contact angle increased, and the properties of the enamel surface changed from hydrophilic to hydrophobic. The properties were tested, the hydrophobic mechanism was studied based on the investigation of the microstructure and the crystal structures of the film by scanning electron microscopy, X-ray diffraction and infrared spectrum analysis.
Preparation and Properties of BC/PPy/TiO2 Composite Membrane
Authors: Zheng Yi , Chen Shi Yan , Tang Lian , Zheng Wei Li , Lu Chuan , Wang Hua Ping
Published: April 2014

Bacterial cellulose (BC) /Polypyrrole (PPy) /TiO2 composite membrane was successfully prepared by in situ chemical oxidation polymerization of pyrrole in TiO2 sol into BC membrane matrix with different concentration of TiO2. The results of the field emission scanning electron microscopy observation revealed that the TiO2 nanoparticles coated with PPy were well homogeneously dispersed in the BC matrix. The photocatalytic activity of composite membrane was measured by methyl orange reaction model. Furthermore, the chemical structure of composite membrane and the anatase-TiO2 crystal structure were characterized by FT-IR spectroscopy and XRD analysis, respectively. According to this study, the photocatalytic activity of composite membranes was improved significantly by the addition of TiO2 due to the synergistic reaction between TiO2 and PPy. Besides that, the membrane exhibited the striking flexibility and mechanical properties. This study provided a green and facile method to prepare the BC /PPy /TiO2 composite membrane which would have potential applications in wastewater treatment.
Preparation and Characterization of Poly(vinylidene) Fluoride Membranes Reinforced by Modified Nano-SiO2 Particles
Authors: Qin Ai Wen , Li Xiang , Ma Bo Mou , Zhao Xin Zhen , Liu Chun Yi , He Chun Ju
Published: April 2014

Poly (vinylidene fluoride) (PVDF) hybrid membranes reinforced by hydrophilic nanoSiO2 particles were fabricated from PVDF/N-dimethylacetamide (DMAc)/γ-butyrolactone (γ-BL) system via thermally induced phase separation (TIPS) process. Surface and cross-sectional morphology of membranes were characterized by scanning electron microscope (SEM). The properties such as permeability, mechanical performances and antifouling property were also determined. The results showed that the pore size of membrane surface became smaller, while cross-sectional morphology was changed from bicontinuous structure to cell structure, the pore size became larger and majorities of closed pores became open with the addition of hydrophilic nanoSiO2 particles in the system. Compared with pure membrane, pure water flux of hybrid membrane increased by 30.3%, i.e. from 290 to 378 L/(m2·h·0.1MPa), antifouling property increased from 63.1% to 80.2%. Meanwhile, tensile strength and elongation at break increased by 70.6% and124%, respectively.
Study on Poly(ether imide)/Amino-Modified Sillica Hybrid Membranes
Authors: Chen Ying , Sun Jun Fen
Published: April 2014

Poly (ether imide) (PEI) membrane with many good properties, such as chemical resistance, biocompatibility, good thermal, and mechanical properties, has been widely used in filtration and biomedical applications. SiO2particles containing amine groups can be a good enzyme immobilization carrier. Organic-inorganic hybrids of poly (ether imide) and amino-modified SiO2were in situ prepared via sol-gel process in the presence of tetraethylortho silicate (TEOS) in a mixed solvent of N, N-Dimethylacetamide/1-Methyl-2-pyrrolidone (DMAc/NMP). The effects of casting solution composition on the membrane morphological structure and performance were investigated. The dispersion of the inorganic and organic phase in the nanoscale was possible with addition of (3-aminopropyl) triethoxysilane (APTES) as shown by field emission electron microscopy. Membranes with different ratio of APTES/TEOS have quite different properties. Mechanical properties evaluation such as rupture elongation ration and tensile strength tests of the hybrid membranes were carried out. Fourier transform infrared spectroscopy (FTIR), pure water fluxes and water contact angle of the hybrid membranes were also characterized. The results show that poly (ether imide)/amino-modified SiO2hybrid membranes have high static adsorption capacity for lysozyme (Lys). Moreover, mechanical properties of the hybrid membranes greatly improve compared to pure PEI membranes.
Strontium-Substituted Hydroxyapatite Nanocrystals Synthesized in Ultrasonic Field: Use for Protein Adsorption
Authors: Cao Wei Ye , Sun Jun Fen
Published: April 2014

Hydroxyapatite Ca10(PO4)6(OH)2(HAP) is widely applied in a biomaterial because of its excellent biocompatibility and bioactivity. However, all properties of HAP, especially the adsorption properties can be tailored by modifying the composition with ionic substitutions. Among many cations that can substitute for calcium in the structure of HAP, strontium is a kind of essential trace elements in human body. It has been known as one of the cationic substitute for calcium in the HAP lattice. The strontium-substituted hydroxyapatite (Sr-HAP) is formed when strontium is doped in HAP structure. The bioactivity, biocompatibility, and adsorption properties are improved when the original lattice of HAP is destroyed. In this study, we focus on synthesis of strontium-substituted HAP nanocrystals in ultrasonic field which is a mild and simple synthesis method. The Sr-HAP with different Sr contents was synthesized. The effects of reaction temperature, sintering temperature and reaction time on protein adsorption of Sr-HAP were studied. In addition, the crystalline phase, chemical compound, surface area and morphology were characterized by XRD, FTIR, TEM and BET. The results indicate that the original lattice of HAP was destroyed and the structure of HAP doped with strontium formed. Sr-HAP with smaller crystal size, larger specific surface area and homogeneous distribution was prepared. Especially, it has great adsorption to target protein, bovine serum albumin (BSA).
The Effect of Bacterial Cellulose (BC) Fiber Content on the Properties of BC Fiber Reinforced Nanocomposites
Authors: Zheng Wei Li , Zhao Si Yu , Zheng Yi , Chen Shi Yan , Wang Hua Ping
Published: April 2014

Optically transparent nanocomposites were prepared by epoxy resin reinforced with bacterial cellulose nanofibers in volume fraction from 2.6 to 32.7wt%. The transparence, surface smoothness, thermal expansion and mechanic properties of the nanocomposites with different BC fiber content were characterized. It was found that the nanocomposites display high visible light transparence (84% at 600nm) even at high fiber content (32.7 wt%). The coefficient of planar thermal expansion (CTE) was reduced from 83.8 ppm/K (Epoxy resin) to 40.6 ppm/K at low fiber content (2.6 wt%). The high transparence was insensitive to the change of temperature from room temperature to 90 oC.
Effects of Cold Rolling Reduction on Deformation Modes in Mg-3Al-1Zn Magnesium Alloy
Authors: Cheng Bo , Guan Lei , Liu Da Bo
Published: April 2014

Activation of different slip and twinning systems in cold-rolled Mg-3Al-1Zn at different thickness reductions was investigated by using orientation distribution function and electron backscattered diffraction techniques. The results show that the activation of slip coincides with the most compressive strain, resulting in little need for deformation twinning. The importance of prismatic slip was reinforced and  pyramidal slip was not a major deformation mechanism during cold rolling. The crystal texture in the cold rolled samples was weakened by twinning but strengthened by slip.
Effect of Dysprosium Content on the Magnetic Properties of Nanocrystalline (Pr0.25Nd0.75)10-xDyxFe82Co2B6 Alloys
Authors: Ding He Wei , Cui Chun Xiang , Sun Ji Bing
Published: April 2014

(Pr0.25Nd0.75)10-xDyxFe82Co2B6(x=0~0.3) ribbons were prepared by melt spinning at 25m/s and subsequent annealing. The effect of Dy content on the microstructure and magnetic properties of the ribbons has been investigated by X-ray diffractometer (XRD), scanning electronic microscope (SEM) and vibrating sample magnetometer (VSM). The magnetic properties related to the Dy content were characterized. Intrinsic coercivity of 598kA/m, remanence of 0.58T, and the maximum energy product (BH)max of 43kJ/m3 were achieved in (Pr0.25Nd0.75)9.8Dy0.2Fe82Co2B6 after annealing at 700°C for 10 minutes.
Study on the Flow Field of Friction Stir Welding of AZ31 Magnesium Alloy Based on the Temperature Variation
Authors: Lu Ali , Lu Sheng , Chen Shu Jin , Yang Dai Li
Published: April 2014

In this study, AZ31 magnesium alloy plates were butt welded by friction stir welding to investigate the flow field characterization, and temperature variation was measured. “Marker insert technology” and “stitch welding of dissimilar materials technique” were used to make the flow field visualization. The results indicated that both the temperature variation and the flow way of material are three dimensional asymmetric. In terms of temperature distribution, along the welding direction, the temperature is gradually increased during the process; along the thickness direction, the peak temperature is high in the upper part and low in the lower; perpendicular to the welding direction, the peak temperature of the advancing side is slightly higher than the retreating side. In terms of the flow field, the flow way of the material in the advancing side is different from retreating side. Material from the advancing side crosses the pin and is divided into two directions: part is dragged forward by the shoulder while part is extruded backward. However, materials in retreating side move backward only. At different depths, the flow range of plastic material is different. The closer to the bottom of the weld, the flow range of plastic material is smaller. Along the welding direction, the flow range of the plastic material changes larger from the initial stage to the end stage. On the cross section of the weld, plastic material that adjacent to the pin is squeezed down while part of the material at the bottom is forced to move upwards. The rising material converged with the downward current and formed a cycle. Considering the deformation tendency of the lapped surface, the advancing side is more intense than the retreating side.
Microstructure Evolution in Isothermal Heat Treatment of 0Cr32Ni7Mo4NDuplex Stainless Steel
Authors: Chen Yu Lai , He Hong , Fang Fei
Published: April 2014

The microstructure evolution of as-cast 0Cr32Ni7Mo4N hyper duplex stainless steel during the isothermal heat treatment in the temperature range of 800°C-1300°Cwas studied in the present investigation. The morphologies and precipitates were observed and determined by using optical microscope (OM), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The results show that eutectoid decomposition reaction (δ→σ+γ2) take place in ferrite (δ) phase during isothermal heat treatment in the temperature range of 800°C-1000°C. Sigma (σ) phase and secondary austenite (γ2) phase coexist as cellular structure. Lamellar Cr2N precipitates in δ phase mostly when isothermal heat treatment at 800°Cand 850°C, while it only appears in γ phase between 900°C and 1050°C. As the annealing temperature rising, the quantity of σ phase, Cr2N and γ2 phase decreases. The volume fraction ratio of ferrite and austenite is stable between 1100°C and 1300°C, and γ → δ transformation is hard to occur.
Effects of Melt Cyclical Superheating Conditions on the Microstructure of FeSi2 Alloy
Authors: Zhang Chi , Zhang Zhi Hao , Jiang Zhi Peng , Wang Wei Li , Xie Jian Xin
Published: April 2014

In order to avoid coarse primary-precipitated ε phase which prolong α+ε→β phase transition time in FeSi2 material prepared by conventional casting, a cyclical superheating process of melt for preparing FeSi2 with complete α+ε eutectic structure was proposed. The effects of melt superheating conditions on the microstructure of FeSi2 were investigated. The results showed that, with the increase of the superheating temperature, the superheating time, the recycling times and the cooling velocity, the size and quantity of the ε phase reduced. Meanwhile, the number of the fine eutectic structure increased. FeSi2 sample with uniform and complete α+ε eutectic structure was successfully prepared in the conditions of melt superheating temperature at 1550°C, superheating time for 10mins, recycling 3 times,melt cooling rate of 30°C/s.
Investigation on Micro Components Fabricated by Micro Powder Injection Molding
Authors: Long Ji Cai , Chen Yu , Li Yu Long , Liu Lin , Yin Hai Qing , Qu Xuan Hui
Published: April 2014

The development of microsystems and related products has caused an upsurge in the mass production of micro components. In the paper, fabrication of zirconia micro gears of 700μm, 800μm, 900μm based on water-soluble binder were investigated. The water-soluble binder system consists of 30%PEG-4000+10%SA+30%PVB+30%EVA components. Experimental results show that zirconia micro gears are successfully fabricated using the in-house feedstock. And the decrease of the molecular weight of water-soluble component is beneficial to the quality of the molded part.
Effect of Temperature on Low Energy Consumption Electrolytic Preparation of Manganese Dioxide Using Oxygen Depolarized Electrode
Authors: Zhang Hui , Meng Hui Min
Published: April 2014

A new method of an oxygen depolarization gas diffusion electrode (GDE) is proposed to reduce the energy consumption of the electrolysis process for electrolytic manganese dioxide (EMD). Substitute oxygen reduction reaction for hydrogen evolution reaction can reduce energy consumption, avoid acid mist, improve working environment, as well as reduce hidden danger. The effect of temperature on electrodeposition was researched. The results show that the cell voltage and the energy consumption of new method by using GDE (Pt/C type) is 4/5-2/3 of that by using Cu or Pt cathode at 40-90°C. The current efficiency is up to 95%, when the temperature is greater than 70°C. The optimum temperature of the new electrolysis process is 80°C, while the life span reaches 400 h. The as-gained EMD belongs to γ-MnO2 when temperature reaches 60°C. The performance of EMD fulfills the industrial requirements when the temperature reaches 70°C. By greatly influence the dissolution rate of Ni net, temperature affects the life span of GDE.
Microstructure and Mechanical Properties of Brazed Tungsten/Steel Joint for Divertor Applications
Authors: Ma Yun Zhu , Cai Qing Shan , Liu Wen Sheng , Liu Shu Hua
Published: April 2014

Due to its excellent thermophysical properties, tungsten has been used as structural materials for divertor components of fusion reactors. With the development of technology, the helium cooled high performance divertor requires the high reliable joining between tungsten and ferritic martensitic high chromium steel. However, the difference of thermal expansion coefficients between tungsten and steel causes high thermally residual stresses, which will yield failure of the joint. Therefore, the preparation of the joint between tungsten and steel is a key issue for divertor application. A brazing process, using rapidly solidified Ni-based foil-type filler and a vanadium slice as intermediate materials, was developed to investigate the joining of tungsten and steel for divertor components, and the microstructure and mechanical properties of the joint were also studied. The elements and phases compositions in the boning regions were analyzed by electron probe microanalysis and X-ray diffraction. Micro-hardness distribution and tensile strength of joint were measured by nanoindenter and mechanical testing machine, respectively. The results indicated that the integral bonding was achieved at the bonding regions of the brazed joint. The typical microstructure of the joint was consisted of W/V and V/steel brazed seams separated by a V slice. The hard and brittle vanadium borides with 25 GPa hardness were produced at the W/V and V/steel brazed seams. The as-bonded W/steel joint with tensile strength of 143MPa was obtained, and specimens appeared a brittle fracture mode and fractured in the brittle vanadium boride layers during tensile testing.
Investigation on the Micro-Structures and Properties of the P20 Steel Surface after Electrical Discharge Machining
Authors: Zhang Xiao Liang , Wang Zhao Xi , Liang Jun , Shi Hui Ji , Matvienko Yu. G.
Published: April 2014

Electrical Discharge Machining (EDM) is the machining technique of discharging corrosion of the material surface. The effect of the EDM pulse current on the micro structure and properties of the P20 specimen surface were investigated. Three layers were observed on the specimen surface after discharging: ablation layer, molten layer and recrystallized layer. The experimental results show that with the increment of the pulse current, the thickness of the molten layer and recrystallized layer increased. The contents of the oxygen and carbon on the outside of the molten layer were higher than the base metal for the diffusion during the machining. The micro hardness reduced from the out layer to the base metal after the heat treatment, indicating the mechanical properties changing of the machining surface. In the molten layer, micro fracture is caused by the residual thermal stress during the machining.
Development and Application of Multivariable Composite Controller Based on Fuzzy Switching for Ultra Fast Cooling System
Authors: Hu Xiao , Wang Bing Xing , Wang Zhao Dong , Wang Guo Dong
Published: April 2014

By the analysis of the conventional PID controller characteristics and the equipment hysteretic nature, one design method of multivariable composite controller based on fuzzy switching was introduced in this paper. The controller solved the problem of local optimal value using fuzzy self-tuning PID controller. As a result of introducing parameter of ultra fast cooling flow setting, response speed of frequency converter was reduced. In order to avoid chattering generated when system switching, fuzzy switching scheme was designed. The simulation results show that response characteristic of the controller is better than conventional PID controller and chattering is smaller during the system switching. Applying the controller into constant pressure water supply system, the control effect is improved obviously.
Effect of Ti Content on the Microstructure and Properties of TiC/TiB2-FeNiCr Composite Prepared by Thermite Reaction
Authors: Liu Yang , Xi Wen Jun , Li Shu Jie
Published: April 2014

TiC/TiB2-FeNiCr composite reinforced by TiC and TiB2 composite ceramic particles was successfully in-situ synthesized using thermite reaction. The effects of Ti content in the raw material on the microstructure and properties of the composite were studied. The microstructure was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The hardness, compressive strength and wear resistance were tested using the Vickers indentation method (HXZ-1000), mechanical testing machine (SANS5105) and the high temperature wear tester (HT-600), respectively. The results show that the composite is mainly consisted of TiC, TiB2, Cr7C3, α-FeNiCr and NiAl. The content of TiC and TiB2 is increased with the Ti content. The hardness and compressive strength of the composite is increased first and then decreased. They attain the maximum value at about 8.0wt%Ti. The hardness and the compressive strength of the composite are 1313.25HV and 2725.57MPa at 8.0% Ti. Also the wear resistance of the composite is good, and the weight wear loss at 8.0% Ti is nearly fifth of the mass loss of steel.