共查询到20条相似文献,搜索用时 15 毫秒
1.
Hansang Kwon Dae Hoon Park Jean François Silvain Akira Kawasaki 《Composites Science and Technology》2010
We have increased the tensile strength without compromising the elongation of aluminum (Al)–carbon nanotube (CNT) composite by a combination of spark plasma sintering followed by hot-extrusion processes. From the microstructural viewpoint, the average thickness of the boundary layer with relatively low CNT incorporation has been observed by optical, field-emission scanning electron, and high-resolution transmission electron microscopies. Significantly, the Al–CNT composite showed no decrease in elongation despite highly enhanced tensile strength compared to that of pure Al. We believe that the presence of CNTs in the boundary layer affects the mechanical properties, which leads to well-aligned CNTs in the extrusion direction as well as effective stress transfer between the Al matrix and the CNTs due to the generation of aluminum carbide. 相似文献
2.
3.
4.
5.
6.
Karl M. Prewo 《Journal of Materials Science》1988,23(8):2745-2752
Carbon fibre reinforced borosilicate glass matrix composites have been fabricated to determine their mechanical properties in tension and flexure. Composite tensile stress-strain properties, including elastic modulus, proportional limit and ultimate tensile strength, have been measured as a function of fibre content. Composite tensile properties were also obtained at temperatures of up to 625° C through the testing of 0/90 cross-plied specimens. Composite short-beam shear strength was found to depend on specimen orientation and also on the composition of the glass matrix. This compositional dependence was associated with an independent measurement of the fibre-matrix interfacial shear strength and was related to the degree of fibre-matrix reaction taking place during composite fabrication. 相似文献
7.
《材料科学技术学报》2017,(9)
Al_(65)Cu_(20)Ti_(15)metallic glass(AMG) reinforced Al matrix composites were consolidated by equal channel angular pressing(ECAP) process. The effects of ECAP consolidation temperature ranging from room temperature to just below the first crystallization temperature of metallic glass on the consolidation of composites were investigated in terms of the relative densities, structural evolutions and mechanical properties of composites. Some intermetallic compounds included Al_5CuTi_2, Al_3Ti and Al_4Cu_9 precipitated from metallic glass particles at consolidation temperature of 300?C. Consolidation temperature did not affect the matrix grains size of the composite. Quantitative analysis revealed that the distribution of reinforcing particles was considerably dependent on consolidation temperature. Density of the composite was increased by increasing the consolidation temperature to 250?C. The composite consolidated at250?C through ECAP process, exhibited the best combination of yield strength and ductility of 184 MPa and 48%, respectively. 相似文献
8.
Cu-coatedwoven carbon fibers/aluminum alloy composite (Cf/Al) was prepared by spark plasma sintering. Microstructure and mechanical properties of the composite were investigated. Microstructure observation indicates that the interface reaction is evidently inhibited by Cu coating. Woven carbon fibers are adhered to the matrix alloy by anchor locking effect of matrix alloy immersing into the interstices between carbon fibers. Under the quasi-static and dynamic compressive conditions, the composite exhibits excellent ductility even when the strain reaches 0.8. Adding carbon fibers into ZL205A alloy has no obvious influence on compressive flow stress of the composite. The compressive true stress–true strain curves show that the composite is a strain rate insensitive material. During the tensile tests, the elongation of the composite shows a sharp increase from 4.5% to 13.5% due to the adding of woven carbon fibers. Meanwhile, the tensile strength of the composite is increased slightly from 168 MPa to 202 MPa compared to that of ZL205A alloy. The good ductility of the composite is ascribed to the cracks deflection, fibers pulling out, debonding and breakage mechanisms. 相似文献
9.
Industrial pure aluminum (0.5 wt% impurity elements) was utilized in many investigations of aluminum matrix composites at
home and abroad. However, impurity elements in industrial pure aluminum may influence the interface during fabrication of
composite at high temperature. Thereby, it is necessary to use high-purity aluminum (impurity elements less than 0.01%) as
matrix to enable study the interface reaction between reinforcement and matrix. In this study, stretches of brittle Al4C3 at the fiber/matrix interfaces in Grf/Al composite were observed. The fracture surface of the composite after tensile and bending tests was flat with no fiber
pull-out, which revealed characteristic of brittle fracture. This was related to Al4C3, as this brittle phase may break before the fiber during loading and become a crack initiation point, while the corresponding
crack may propagate in the fiber and the surrounding aluminum matrix, finally resulting in low stress fracture of composites. 相似文献
10.
11.
Flexural properties of glass fiber reinforced composite with multiphase biopolymer matrix 总被引:6,自引:0,他引:6
Väkiparta M Yli-Urpo A Vallittu PK 《Journal of materials science. Materials in medicine》2004,15(1):7-11
The aim of this study was to evaluate flexural properties of glass fiber-reinforced composites with a multiphase biopolymer matrix. Continuous unidirectional E-glass fibers were preimpregnated with a novel biopolymer of poly(hydroxyproline) amide and ester. The preimpregnated fibers were then further impregnated in a co-monomer system of Bis-GMA-TEGDMA, which formed semi-interpenetrating polymer networks (semi-IPN) with the preimpregnated polymer. After light initiated polymerization of the monomer system, rectangular shaped bar specimens (n = 4) were tested by the three-point bending test. The control material was a fiber-reinforced composite with a Bis-GMA-TEDGMA-matrix only. The mean flexural strength of poly(hydroxyproline) amide preimpregnated fiber composite was higher than that of the control (FS = 888 vs. 805 MPa). The poly(hydroxyproline) ester preimpregnated fibers resulted in lower strength (FS = 541 MPa). The results of this study suggest that preimpregnation of glass fibers with poly(hydroxyproline) amide and the use of such fibers in fiber-reinforced composites with IPN polymer matrices, can reach relatively high mechanical properties. 相似文献
12.
通过填加造孔剂方法制备了碳纳米管(CNTs)增强铝基复合泡沫,采用热机械分析仪研究了测试温度、频率、外加振幅、泡沫的孔隙率和CNTs含量对其阻尼性能的影响,并分析了相关阻尼机制。结果表明:复合泡沫铝的阻尼性能随孔隙率和振幅的增大而提高,随着频率的增加而下降。在环境测试温度25~200℃范围内,复合泡沫的损耗因子变化较小;当温度高于200℃后,损耗因子随温度升高有明显的提高。CNTs的加入可以显著提高泡沫铝的阻尼性能,常温下3.0% CNTs增强的铝基复合泡沫的损耗因子达0.27,为泡沫铝的3.71倍。复合泡沫的阻尼机制主要为位错阻尼、晶界阻尼、孔隙阻尼、CNTs的本征阻尼和CNTs-Al间界面阻尼,其中本征和界面阻尼发挥了重要的增强作用。 相似文献
13.
《Materials Letters》2004,58(3-4):333-336
The microstructure and micro-yield strength of sub-micron Al2O3 particle reinforced 2024Al composites and the effect of the thermal-cold cycling treatment on the microstructure and properties were studied. The results show that the dislocations are rare in the microstructure of the sub-micron Al2O3p/2024Al composite in the squeeze casting condition. Aging and thermal-cold cycling treatment does not change this phenomenon. The Al2O3 particles are fine, so the thermal misfit between particles and the matrix is very small during the temperature change, resulting in decreased dislocations. The tiny and uniformly dispersed S′ precipitates and sub-micron particles can effectively pin dislocations, therefore, the micro-yield strength of the composite increases. Depending on the condition of the thermal-cold cycling treatment after aging, both the size and distribution of the S′ precipitates in the composite change, and they have great effect on the micro-yield strength of the composite. 相似文献
14.
Aluminum (Al) matrix composite materials reinforced with carbon nanotubes (CNT) and silicon carbide nanoparticles (nano-SiC) were fabricated by mechanical ball milling, followed by hot-pressing. Nano-SiC was used as an active mixing agent for dispersing the CNTs in the Al powder. The hardness of the produced composites was dramatically increased, up to eight times higher than bulk pure Al, by increasing the amount of nano-SiC particles. A small quantity of aluminum carbide (Al(4)C(3)) was observed by TEM analysis and quantified using x-ray diffraction. The composite with the highest hardness values contained some nanosized Al(4)C(3). Along with the CNT and the nano-SiC, Al(4)C(3) also seemed to play a role in the enhanced hardness of the composites. The high energy milling process seems to lead to a homogeneous dispersion of the high aspect ratio CNTs, and of the nearly spherical nano-SiC particles in the Al matrix. This powder metallurgical approach could also be applied to other nanoreinforced composites, such as ceramics or complex matrix materials. 相似文献
15.
《Composites Science and Technology》2006,66(11-12):1793-1802
The tensile properties and thermal expansion behaviors of continuous molybdenum fiber reinforced aluminum matrix composites (Mof/Al) have been studied. The Mof/Al composites containing different volume percents of Mo fibers were processed by diffusion bonding. The strengths of unidirectional Mof/Al composites were close to the rule-of-mixtures. The strengths of 0°/90° dual-directional composites increased with fiber content, while those of 45°/135° composites remained relatively low. The coefficients of thermal expansion (CTEs) of the composites decreased as the fiber content increased, close to the values of Mo fibers. With increasing temperature, the CTEs of unidirectional composites increased, while those of dual-directional composites decreased due to large accumulated thermal stresses. The CTEs of 45°/135° composites were lower than those of 0°/90° composites because of contraction effect. At temperatures above 250 °C, the CTEs of the dual-directional composites gradually increased due to matrix yielding and interfacial decohesion. 相似文献
16.
17.
18.
ZnO-coated aluminum borate whiskers reinforced 2024Al composite was fabricated by squeeze casting. Interfacial microstructures and tensile properties of the composite in as-cast and after thermal exposure were investigated. Fracture mechanisms of the composite in as-cast and after thermal exposure were also investigated. The results show that ZnO coating of the whiskers reacts with molten 2024Al and MgAl2O4 forms at the interface during squeeze casting. On the one hand, the interfacial reaction between ZnO and 2024Al can improve the wettability of the whiskers by molten 2024Al, increasing the tensile properties of as-cast composite. On the other hand, during thermal exposure, MgAl2O4 at the interface can effectively hinder serious interfacial reactions between the whiskers and magnesium in the matrix of 2024Al, improving the thermal stability of the composite at high temperatures. 相似文献
19.
Fabrication and evaluation of mechanical and tribological properties of boron carbide reinforced aluminum matrix nanocomposites 总被引:1,自引:0,他引:1
In this study, fabrication and characterization of bulk Al–B4C nanocomposites were investigated. B4C nanoparticles were mixed with pure Al powder by ball milling to produce Al–B4C powder. Al–B4C powders containing different amounts of B4C (5, 10 and 15 wt.%) were subsequently hot pressed to produce bulk nanocomposite samples. Consolidated samples were characterized by hardness, compression and wear tests. Results showed that the sample with 15 wt.% B4C had the optimum properties. This sample had a value of 164 HV which is significantly higher than 33 HV for pure Al. Also, ultimate compressive strength of the sample was measured to be 485 MPa which is much higher than that for pure Al (130 MPa). The wear resistance of the nanocomposites increased significantly by increasing the B4C content. Dominant wear mechanisms for Al–B4C nanocomposites were determined to be formation of mechanical mixed layer on the surface of samples. 相似文献
20.
Metal matrix composites comprising aluminum matrix and multi-wall carbon nanotubes (MWCNTs) as reinforcements are fabricated
using cold uniaxial compaction followed by sintering and cold extrusion as secondary processes. The MWCNTs are pretreated
with sodium dodecyl sulfate for improved adhesion with aluminum powder. The effect of sintering temperature on the microstructure
is explored using differential scanning calorimetric spectrum. The tensile yield and ultimate strength of Al-MWCNTs increased
to 90% with 2 wt% addition of MWCNTs. Various theories for the strengthening and stiffening of Al-MWCNTs composites are explored. 相似文献