共查询到20条相似文献,搜索用时 31 毫秒
1.
Kimiyoshi Naito 《Journal of Materials Science》2013,48(12):4163-4176
The tensile properties and fracture behavior of polyacrylonitrile (PAN)- and pitch-based hybrid carbon fiber/polyimide composites with several types of nanoparticles (25 nm C, 20–30 nm β-SiC, 130 nm β-SiC, 80 nm SiO2, and 300 nm SiO2) added to the matrix were investigated. The tensile stress–strain curves of PAN- and pitch-based hybrid carbon fiber/polyimide composites with 25 nm C, 20–30 nm β-SiC, and 80 nm SiO2 nanoparticles have complex shapes (jagged trace), whereas the tensile response of hybrid carbon fiber/polyimide composites with 130 nm β-SiC and 300 nm SiO2 nanoparticles indicates an instantaneous failure. The stress after the initial failure in hybrid carbon fiber/polyimide composites improves by adding 25 nm C, 20–30 nm β-SiC, and 80 nm SiO2 nanoparticles to the matrix and correlates with the fracture toughness of the polyimide matrix. 相似文献
2.
Hydrophilic microparticle and nanoparticle-filled isotactic polypropylene (iPP) composites containing 5 wt% particles were
extruded in a Berstorff extruder and then injection molded. For characterization the tensile and unnotched Charpy impact tests
were performed. The results show that significant improvements in tensile strength, yield elongation, and unnotched impact
strength are achieved in iPP/nanoparticle composite based on a good dispersion quality of nanoparticles. In the case of iPP/microparticle
composite, the tensile modulus and yield strength are markedly increased compared to neat matrix, but the yield elongation
and unnotched impact strength are drastically decreased due to broad size distribution of microparticles. The fracture mechanisms
were discussed by studying surface morphology of failed samples. Furthermore, the influence of crystalline behavior on mechanical
properties of iPP composites was discussed. 相似文献
3.
Preparation of epoxy/SiO2-TiO2 composites is investigated in this paper. The products are characterized by FT-IR spectroscopy. Results of FT-IR spectroscopy and atom force microscope (AFM) demonstrated that epoxy chains have been covalently bonded to the surface of the SiO2-TiO2 particles. The particles sized of SiO2-TiO2 are about 20–50 nm, which characterized by AFM. The properties of composites such as impact strength, flexural strength, tensile strength and ring-on-block wear are also investigated. Dry sliding wear tests showed that the SiO2-TiO2 particles could improve the wear resistance of the epoxy matrix even though the content of the SiO2-TiO2 particles was at a relatively low level (1.95–2.65 wt%). This makes it possible to develop novel type of epoxy-based materials with improved wear resistance for various applications. The worn surface was observed by scanning electron microscopy (SEM), and mechanisms for the improvement are discussed in this paper 相似文献
4.
The B4C-ZrB2-SiC ternary composites with super hard and high toughness were obtained by arc melting in argon atmosphere. Microstructures were observed by SEM, and phase compositions were analyzed by XRD. The hardness and fracture toughness of ternary composites are 28 GPa and 4.5 MPa·m1/2. The eutectic mole composition is 0.39B4C-0.25ZrB2-0.36SiC, and the eutectic lamellar microstructure is composed of B4C matrix with the lamellar ZrB2 and SiC grains. 相似文献
5.
Quanlin Zhao Zhijun Jia Xiaogang Li Zhengfang Ye 《Journal of Failure Analysis and Prevention》2010,10(6):515-519
The effect of particle fraction on mechanical properties of particle-reinforced composites was studied using tensile and hardness
testing. Unsaturated polyester (UP) was used as polymer matrix, and aluminum hydroxide as the reinforcing particles. The fracture
morphology of tensile samples was observed by scanning electron microscopy (SEM). The results showed that the tensile strength
and absorbed energy increased to a maximum at 10% particle content and then decreased. With increasing content of aluminum
hydroxide, the elastic modulus increased, and the fracture elongation decreased. The SEM showed that the failure of the Al(OH)3/UP composites was one of macroscopically brittle fracture. In addition, the study showed that appropriate amount of filler
can enhance the surface hardness of Al(OH)3/UP composite. 相似文献
6.
A. Canakci 《Journal of Materials Science》2011,46(8):2805-2813
In this study, the microstructure and abrasive wear properties of varying volume fraction of particles up to 12% B4C particle reinforced 2014 aluminium alloy metal matrix composites produced by stircasting method was investigated. The density,
porosity and hardness of composites were also examined. Wear behaviour of B4C particle reinforced aluminium alloy composites was investigated by a block-on-disc abrasion test apparatus where the samples
slid against the abrasive suspension mixture (contained 10 vol.% SiC particles and 90 vol.% oil) at room conditions. Wear
tests performed under 92 N against the abrasive suspension mixture with a novel three body abrasive. For wear behaviour, the
volume loss and specific rate of the samples have been measured and the effects of sliding time and the content of B4C particles on the abrasive wear properties of the composites have been evaluated. The dominant wear mechanisms were identified
using SEM. Microscopic observation of the microstructures revealed that dispersion of B4C particles was generally uniform while increasing volume fraction led to agglomeration of the particles and porosity. The
density of the composite decreased with increasing reinforcement volume fraction but the porosity and hardness increased with
increasing particle content. Moreover, the specific wear rate of composite decreased with increasing particle volume fraction.
The wear resistance of the composite was found to be considerably higher than that of the matrix alloy and increased with
increasing particle content. 相似文献
7.
Polypropylene (PP) composites with 5 wt% of different rigid particles (Al2O3 nanoparticles, SiO2 nanoparticles, Clay (Cloisite 20A) nanoparticles or CaCO3 microparticles) were obtained by melt mixing. Composites with different CaCO3 content were also prepared. The effect of fillers, filler content and addition of maleic anhydride grafted PP (MAPP) on the composites fracture and failure behavior was investigated. For PP/CaCO3 composites, an increasing trend of stiffness with filler loading was found while a decreasing trend of strength, ductility and fracture toughness was observed. The addition of MAPP was beneficial and detrimental to strength and ductility, respectively mainly as a result of improved interfacial adhesion. For the composites with 5 wt% of CaCO3 or Al2O3, no significant changes in tensile properties were found due to the presence of agglomerated particles. However, the PP/CaCO3 composite exhibited the best tensile behavior: the highest ductility while keeping the strength and stiffness of neat PP. In general, the composites with SiO2 or Clay, on the other hand, displayed worse tensile strength and ductility. These behaviors could be probably related to the filler ability as nucleating agent. In addition, although the incorporation of MAPP led to improved filler dispersion, it was damaging to the material fracture behavior for the composites with CaCO3, Al2O3 or Clay, as a result of a higher interfacial adhesion, the retardant effect of MAPP on PP nucleation and the lower molecular weight of the PP/MAPP blend. The PP/MAPP/SiO2 composite, on the other hand, showed slightly increased toughness respect to the composite without MAPP due to the beneficial concomitant effects of the presence of some amount of the β crystalline phase of PP and the better filler dispersion promoted by the coupling agent which favor multiple crazing. From modeling of strength, the effect of MAPP on filler dispersion and interfacial adhesion in the PP/CaCO3 composites was confirmed. 相似文献
8.
A. Sakthivel R. Palaninathan R. Velmurugan P. Raghothama Rao 《Journal of Materials Science》2008,43(22):7047-7056
In this study, 2618 aluminum alloy metal matrix composites (MMCs) reinforced with two different sizes and weight fractions
of SiCp particles upto 10% weight were fabricated by stir cast method and subsequent forging operation. The effects of SiCp particle content and size of the particles on the mechanical properties of the composites such as hardness, tensile strength,
hot tensile strength (at 120 °C), and impact strength were investigated. The density measurements showed that the samples
contained little porosity with increasing weight fraction. Optical microscopic observations of the microstructures revealed
uniform distribution of particles and at some locations agglomeration of particles and porosity. The results show that hardness
and tensile strength of the composites increased, with decreasing size and increasing weight fraction of the particles. The
hardness and tensile strength of the forged composites were higher than those of the cast samples. 相似文献
9.
Hongxia Yan Rongchang Ning Guozheng Liang Ying Huang Tingli Lu 《Journal of Materials Science》2007,42(3):958-965
The polymer composites filled with nanoparticles have good friction and wear properties and widely used in many fields. The
performances of nanocomposites are influenced extensively by the nanoparticles morphology, size, volume fraction and dispersion.
Nanometer ZrO2 particles have good properties, lower prices and shows good foreground in resist-materials of polymer composites. In this
paper, the nanometer ZrO2 particles are treated by silane coupling agent of N-(2-aminoethyl)-γ-aminopropylmethyl dimethoxy silane. The effect of nanometer
ZrO2 content and silane coupling agent on the friction and wear properties of BMI copmposites filled with nanometer ZrO2 are investigated. The composites filled with untreated ZrO2 and treated ZrO2 are prepared by the same way of mechanical high shear dispersion process and casting method. The sliding wear performance
of the nanocomposites is studied on an M-200 friction and wear tester. The experimental results indicate that the frictional
coefficient and the wear rate of the composites can be reduced by filled with nanometer ZrO2. The composites containing treated nanometer ZrO2 have the better tribological performance than that containing untreated nanometer ZrO2. The results are explained from the SEM morphologies of the worn surface of matrix resin and the composites containing nanometer
ZrO2 and the TEM photographs of the nanometer ZrO2 dispersion in the matrix. 相似文献
10.
A liquid carboxyl-terminated butadiene–acrylonitrile copolymer (CTBN) and SiO2 particles in nanosize were used to modify epoxy, and binary CTBN/epoxy composites and ternary CTBN/SiO2/epoxy composites were prepared using piperidine as curing agent. The morphologies of the composites were observed by scanning electron microscope (SEM) and transmission electron microscope (TEM), and it is indicated that the size of CTBN particles increases with CTBN content in the binary composites, however, the CTBN particle size decreases with the content of nanosilica in the ternary composites. The effects of CTBN and nanosilica particles on the mechanical and fracture toughness of the composites were also investigated, it is shown that the tensile mechanical properties of the binary CTBN-modified epoxy composites can be further improved by addition of nanosilica particles, moreover, obvious improvement in fracture toughness of epoxy can be achieved by hybridization of liquid CTBN rubber and nanosilica particles. The morphologies of the fractured surface of the composites in compact tension tests were explored attentively by field emission SEM (FE-SEM), it is found that different zones (pre-crack, stable crack propagation, and fast crack zones) on the fractured surface can be obviously discriminated, and the toughening mechanism is mainly related to the stable crack propagation zone. The cavitation of the rubber particles and subsequent void growth by matrix shear deformation are the main toughening mechanisms in both binary and ternary composites. 相似文献
11.
SiCf/SiO2 composites had been fabricated efficiently by Sol-Gel method. The oxidation behavior, thermal shock property and ablation behavior of SiCf/SiO2 composites was investigated. SiCf/SiO2 composites showed higher oxidation resistance in oxidation atmosphere, the flexural strength retention ratio was larger than 90.00%. After 1300 °C thermal shock, the mass retention ratio was 97.00%, and the flexural strength retention ratio was 92.60%, while after 1500 °C thermal shock, the mass retention ratio was 95.37%, and the flexural strength retention ratio was 83.34%. After 15 s ablation, the mass loss rate was 0.049 g/s and recession loss rate was 0.067 mm/s. The SiO2 matrix was melted in priority and becomes loosen and porous. With the ablation going on, the oxides were washed away by the shearing action of the oxyacetylene flame. The evaporation of SiO2 took away large amount of heat, which is also beneficial to the protection for SiCf/SiO2 composites. 相似文献
12.
Hai-Rong Mao Ping Shen Yu-Hua Liu Yu-Guang Zhao Qi-Chuan Jiang 《Journal of Materials Science》2018,53(17):12167-12177
We developed a facile and low-cost approach to prepare lightweight and high-strength magnesium–matrix composites with a nacre-inspired laminated structure. First, lamellar Mg2B2O5 whisker (Mg2B2O5w) scaffolds with initial solid loadings of 10, 15 and 20 vol% were prepared by ice templating. The wettability between a molten AZ91D alloy and the Mg2B2O5w scaffold was greatly improved by the incorporation of nano-SiO2 sol in the aqueous slurry, making the preparation of nacre-mimetic AZ91D/Mg2B2O5w composite by way of pressureless infiltration feasible. The SiO2 content in the Mg2B2O5w scaffold has a significant effect on the processing and the microstructure and properties of the composites. The optimum SiO2 content was about 6–8 wt% of the total ceramic loading. A lower SiO2 content resulted in incomplete infiltration, while a higher content led to the formation of a large quantity of Mg2Si in the composite. The flexural strength of the composites seemed independent of the initial ceramic loading (10–20 vol%), whereas the compressive strength and elastic modulus increased considerably and the crack-growth fracture toughness decreased with increasing ceramic content. The mechanism for such variations was addressed. 相似文献
13.
SiO2 matrix composites doped with AlN particles were prepared by hot-pressing process. Mechanical properties of SiO2 matrix composites can be greatly improved by doping with AlN particles. Flexural strength and fracture toughness of 30 vol%AlN-SiO2 composite sintered at 1400°C reached 200 MPa and 2.96 MPa·m1/2. XRD analysis indicated that, up to 1400°C, no chemical reaction occurred between SiO2 matrix and AlN particles suggesting an excellent chemical compatibility of SiO2 matrix with AlN particles. The influences of hot-pressing temperature and the content of AlN particles on dielectric properties of SiO2-AlN composites were studied. The temperature and frequency dependency of dielectric properties of SiO2-AlN composites were also studied. Residual flexural strength of SiO2-AlN composites decreased with increasing temperature difference. The critical temperature difference was estimated about 600°C. 相似文献
14.
Composite Bi2Te3/SiO2 nanoparticles of the core-shell type have been synthesized for the first time with a view to creating bulk composites possessing high thermoelectric figure of merit (conversion efficiency). It is suggested that bulk composited based on Bi2Te3/SiO2 nanoparticles will provide a combination of low lattice heat conduction due to SiO2 insulator and rather high electric conduction due to charge-carrier tunneling via dielectric spacers between adjacent Bi2Te3 semiconductor grains. The electric resistance of the composite increases with increasing temperature in the range of 130–300 K. This temperature dependence can be described in terms of a tunneling conduction model. 相似文献
15.
In recent years, aluminum alloy based metal matrix composites (MMC) are gaining importance in several aerospace and automobile
applications. Aluminum 6061 has been used as matrix material owing to its excellent mechanical properties coupled with good
formability and its wide applications in industrial sector. Addition of SiCp as reinforcement in Al6061 alloy system improves its hardness, tensile strength and wear resistance. In the present investigation
Al6061-SiCp composites was fabricated by liquid metallurgy route with percentages of SiCp varying from 4 wt% to 10 wt% in steps of 2 wt%. The cast matrix alloy and its composites have been subjected to solutionizing
treatment at a temperature of 530°C for 1 h followed by quenching in different media such as air, water and ice. The quenched
samples are then subjected to both natural and artificial ageing. Microstructural studies have been carried out to understand
the nature of structure. Mechanical properties such as microhardness, tensile strength, and abrasive wear tests have been
conducted both on matrix Al6061 and Al6061-SiCp composites before and after heat treatment. However, under identical heat treatment conditions, adopted Al6061-SiCp composites exhibited better microhardness and tensile strength reduced wear loss when compared with Al matrix alloy. 相似文献
16.
《Advanced Powder Technology》2019,30(9):1782-1788
Epoxy resin-grafted SiO2 nanoparticles stabilized in toluene were successfully designed by the simultaneous surface modification of SiO2 nanoparticles during bead milling which involves the adsorption of polyethyleneimine-oleic acid complex (PEI-OA) and epoxy resin grafting to the free amine groups of PEI-OA (PEI-OA-Epoxy). The effectiveness of epoxy grafting on the properties of the SiO2/epoxy based nanocomposites were investigated using a bead-milled SiO2/toluene suspension stabilized with PEI-OA, PEI-OA-Epoxy, and a complex of PEI and an anionic surfactant comprising an epoxy-soluble polyethylene glycol-based chain (PEI-AS). While SiO2 nanoparticles were pulverized with similar sizes (c.a. 126–171 nm) and stabilized in toluene with any of the three surface modifications, PEI-OA-stabilized SiO2 nanoparticles aggregated during processing epoxy-based composites. PEI-AS- and PEI-OA-Epoxy-stabilized SiO2 nanoparticles maintained their dispersion stability, however, the epoxy composites with PEI-OA-Epoxy-stabilized SiO2 nanoparticles exhibited better material properties, such as increase in the strain at fracture and higher Tg. 相似文献
17.
Hai-Long Wang Chang-An Wang De-Liang Chen Hong-Ling Xu Hong-Xia Lu Rui Zhang Lun Feng 《材料科学前沿(英文版)》2010,4(3):276-280
ZrB2-SiC ultra-high temperature ceramic composites reinforced by nano-SiC whiskers and SiC particles were prepared by microwave sintering at 1850°C. XRD and SEM techniques were used to characterize the sintered samples. It was found that microwave sintering can promote the densification of the composites at lower temperatures. The addition of SiC also improved the densification of ZrB2-SiC composites and almost fully dense ZrB2-SiC composites were obtained when the amount of SiC increased up to 30vol.%. Flexural strength and fracture toughness of the ZrB2-SiC composites were also enhanced; the maximum strength and toughness reached 625 MPa and 7.18 MPa·m1/2, respectively. 相似文献
18.
M. Mumtaz Zafar Iqbal M. Raza Hussain Liaqat Ali M. Waqee-ur-Rehman M. Saqib 《Journal of Superconductivity and Novel Magnetism》2018,31(5):1315-1321
Sol-gel and solid-state reaction methods were used to synthesize diamond nanoparticles (DNPs) and (DNPs) x /CuTl-1223 (x = 0, 0.25, 0.50, and 1.00 wt.%) nanoparticle-superconductor composites, respectively. Effects of these DNPs on structural, morphological, compositional, and transport properties of CuTl-1223 superconducting phase were investigated by different experimental techniques such as X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), and resistivity versus temperature (R-T) measurements. The unchanged crystal structure and stoichiometry of host CuTl-1223 superconducting matrix with addition of DNPs gave evidence about the dispersion of nanoparticles at the grain boundaries of the host matrix, which may heal up the inter-granular voids and pores resulting in enhanced inter-grain connectivity. Critical transition temperature T c (0) and hole concentration of CuTl-1223 superconductor were observed to be increased with addition of DNPs up to a certain optimum value (i.e. x = 0.5 wt.%). 相似文献
19.
SiO2/epoxy nanocomposites were prepared using diglycidyl ether of bisphenol-F (DGEBF) type epoxy and tetraethylorthosilicate (TEOS) via the sol-gel process. Silica nanoparticles were collected after burning off the matrix resin and the silica nanoparticles were observed using TEM. The cryogenic tensile properties at 77 K and thermal expansion coefficient of the nanocomposites were studied. The tensile properties at room temperature were also given to compare with the cryogenic tensile properties. The fracture surfaces were examined with scanning electron microscopy (SEM). The effects of silica nanoparticle content have been studied on the cryogenic tensile and thermal properties of the nanocomposites. In addition, the dependence of the glass transition temperature on the silica nanoparticle content has also been examined. 相似文献
20.
PVC composites filled with CaCO3 particles with different diameter (about 40, 80, 500, 25000 nm) were prepared by using a single-screw extruder. The mechanical
and rheological properties of the composites were investigated. The results showed that while the diameter of CaCO3 nanoparticles was smaller, the mechanical properties of composites were higher. By adding 40-nm CaCO3 nanoparticles into the PVC matrix, the single-notched impact strength of the nanocomposite at room temperature reached 82.4 kJ/m2, which was 3.5 times that of the PVC matrix without CaCO3 (23.3 kJ/m2) and 4.6 times that of the PVC blend filled with micro-CaCO3 (17.9 kJ/m2). The tensile and flexural properties of nanocomposites were also prior to those of the composites with 500-nm and 25-μm
CaCO3 particles. The CaCO3 particles could make the rheological property of PVC composites worse. Moreover, the effect of mass ratio of nano-CaCO3 and micro-CaCO3 on the properties of PVC door and window profile in industry was studied. When the mass ratio was 2.5/9, the profile could
obtain good mechanical properties. 相似文献