Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Fracture Toughness of Carbon Nanotube-Reinforced Metal- and Ceramic-Matrix Composites
Y. L. Chen,B. Liu,Y. Huang,K. C. Hwang
Journal of Nanomaterials , 2011, DOI: 10.1155/2011/746029
Abstract: Hierarchical analysis of the fracture toughness enhancement of carbon nanotube- (CNT-) reinforced hard matrix composites is carried out on the basis of shear-lag theory and facture mechanics. It is found that stronger CNT/matrix interfaces cannot definitely lead to the better fracture toughness of these composites, and the optimal interfacial chemical bond density is that making the failure mode just in the transition from CNT pull-out to CNT break. For hard matrix composites, the fracture toughness of composites with weak interfaces can be improved effectively by increasing the CNT length. However, for soft matrix composite, the fracture toughness improvement due to the reinforcing CNTs quickly becomes saturated with an increase in CNT length. The proposed theoretical model is also applicable to short fiber-reinforced composites.
Preparation of super-aligned carbon nanotube-reinforced nickel-matrix laminar composites with excellent mechanical properties  [PDF]
Ze-cheng Hou,Lun-qiao Xiong,Yuan-feng Liu,Lin Zhu,Wen-zhen Li
- , 2019, DOI: https://doi.org/10.1007/s12613-019-1717-9
Abstract: A homogeneous and compact super-aligned carbon nanotube (SACNT)-reinforced nickel-matrix composite was successfully prepared by electrodeposition. The mechanical properties of the laminar SACNT/Ni composites were substantially improved compared with those of pure nickel. With increasing content of SACNTs, the tensile strength of the composite increased and the elongation decreased because of the high-strength SACNTs bearing part of an applied load and the fine-grained strengthening mechanism. The nanohardness of the SACNT/Ni composites was improved from 3.92 GPa (pure nickel) to 4.62 GPa (Ni?4vol%SACNTs). The uniform distribution of SACNTs in the composites and strong interfacial bonding between the SACNTs and the nickel matrix resulted in an improvement of the mechanical properties of the SACNT/Ni composites. The introduced SACNTs refined the nickel grains, increased the amount of crystal twins, and changed the preferred orientation of grain growth.
Carbon Nanotube Reinforced Aluminium Matrix Composites – A Review
International Journal of Innovative Research in Science, Engineering and Technology , 2013,
Abstract: The present paper illustrates mixing procedures for Al-CNTs powder preparation alongside depiction of the CNTs dispersion results from the different mixing techniques. XRD analysis showed that the mean grain size of powders milled for 6 h was found to be 48.4 nm and for extrudates of CNT-Al, it is 56.6 nm. Based on the geometry and physical properties of multiwalled nanotubes, three strengthening mechanisms were considered for CNT/Al composite system. It was evident from the testing that as the content of nanotubes in the matrix increased, the micro-hardness measured on the Vickers scale also increased. The investigation of the damping behaviour of 2024Al-CNT composite showed that the damping capacity of the composite with a frequency of 0.5 Hz reaches 975 x 10-3, and the storage modulus is 82.3 GPa when the temperature is 400 C, which shows that CNTs are a promising reinforcement for metal matrix composites to obtain high damping capabilities at an elevated temperature without sacrificing the mechanical strength and stiffness of a metal matrix.
Damage analysis of the ceramic reinforced steel matrix composites sheets: experimental and numerical study  [PDF]
E. Bayraktar,F. Ayari,D. Katundi,J.-P. Chevalier
Journal of Achievements in Materials and Manufacturing Engineering , 2011,
Abstract: Purpose: of this paper reports damage analysis of TiB2 (ceramic particles) reinforced steel matrix composite sheets. This new steel composite receives much attention as potential structural materials due to their high specific strength and stiffness. The goal of the research described in this paper is to study the usage of this new steel family in the manufacture of light structures.Design/methodology/approach: therefore in this study is focused to the titanium diboride TiB2 reinforced steel matrix composite sheets that they were characterized by optical and scanning electron microscopes after the mechanical tests carried out on the base metal and welded specimens under dynamic and static test conditions.Findings: The non homogeneity of the structure in this type of composites makes deeply complexity of their numerical and analytical modelling to predict their damage during the loading. For example, the interfaces essentially play a key role in determining mechanical and physical properties. For this reason, a Finite Element (FEM) analysis is used for modelling to simulate the macroscopic behaviour of this material, taking into account the relevant microscopic scales.Practical implications: defined in this research is based on the impact dynamic behaviour of this steel sheets by using a special impact tensile test developed formerly that all details were published in this journal. This type of test gives more comprehensible information about special steel sheets (welded or base metal) in case of dynamic crash conditions.Originality/value: The present research gives detail information on the new steel matrix composite sheets reinforced TiB2 ceramic particles. This new composite was developed by ARCELOR research group and impact dynamic behaviour and weldability of the welded parts and base metals from this composite steel are discussed here in order to give practical and useful solution for industrial applications.
Ablation Properties of C Fibers and SiC Fibers Reinforced Glass Ceramic Matrix Composites Upon Oxyacetylene Torch Exposure  [PDF]
Julien Beaudet, Jonathan Cormier, André Dragon, Magali Rollin, Guillaume Benoit
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.210189
Abstract: The ablation properties of two laminated composites, having both a glass ceramic matrix and different kinds of fibers (C or SiC) with the same architecture, are evaluated and compared. Ablation tests are performed using an oxyacetylene torch on samples having two different thicknesses. Mass loss and ablation depth are measured after flame exposure. The results obtained show that the decomposition of SiC fibers during thermal exposure has a significant impact on ablation behavior. Oxidation of SiC produces a liquid SiO2 film at the top of the material during ablation. This leads to an improved ablation resistance compared to the glass ceramic matrix/C composite, especially in case of successive flame exposures where the SiO2 film consumes a substantial fraction of the heat flow during its liquefaction upon re-heating.
Effect of Carbon Nanotube Size on Compressive Strengths of Nanotube Reinforced Cementitious Composites  [PDF]
Tanvir Manzur,Nur Yazdani,Md. Abul Bashar Emon
Journal of Materials , 2014, DOI: 10.1155/2014/960984
Abstract: Application of nanoscale science to construction material has already begun. In recent times, various nanofibers have raised the interest of researchers due to their exceptional mechanical properties and high potential to be used as reinforcement within cement matrix. Carbon nanotube (CNT) is one of the most important areas of research in the field of nanotechnology. The size and exceptional mechanical properties of CNT show their high potential to be used to produce high performance next generation cementitious composites. In this study, an attempt has been made to investigate the effect of size of CNTs on compressive strengths of CNT reinforced cement composites. Seven different sizes of multiwalled nanotubes (MWNTs) were used to produce MWNT-cement composites. A trend was observed regarding the effect of nanotube size on compressive strength of composites in most cases. MWNT with outside diameter (OD) of 20?nm or less exhibited relatively better performance. Smaller MWNT can be distributed at much finer scale and consequently filling the nanopore space within the cement matrix more efficiently. This in turn resulted in stronger composites.
The Tribological Behavior of Aluminum-matrix Composites Reinforced with Ceramic Particulates in Dry Sliding against a Semi metallic Frictional Material

CHE Yue,XING Jian dong,ZHANG Yong zhen,SHEN Bai ling,NI Feng,

摩擦学学报 , 2001,
Abstract: The tribological behavior of Al alloy matrix composites reinforced with ceramic particulates (SiC p and Al 2O 3) in dry sliding against a semi metallic frictional material was investigated with a disk on block friction and wear tester. The worn surface morphologies of the composites and the counterpart semi metallic frictional material were observed with a scanning electron microscope. It has been found that the composites reinforced with SiC p are superior to the composites reinforced with Al 2O 3 in terms of the tribological behavior. The The composites reinforced with SiC p particulates of larger size and/or volume fraction show greatly increased wear resistance and slightly decreased friction coefficient. The particulate reinforced Al alloy matrix composites have wear rates as lowas 0.1% of the matrix alloy, which corresponds to largely decreased of the wear rate of the counterpart frictional material as well.
Preparation of SiBN fiber reinforced SiBN ceramic matrix composites by precursor infiltration-pyrolysis method

- , 2015, DOI: 10.13801/j.cnki.fhclxb.20140704.002
Abstract: 连续纤维增强氮化物陶瓷基复合材料是耐高温透波材料的主要发展方向,纤维是目前制约耐高温透波复合材料发展的关键,而SiBN陶瓷纤维是一种兼具耐高温、透波、承载的新型陶瓷纤维。以聚硅氮烷为陶瓷先驱体,以SiBN连续陶瓷纤维为增强体,采用先驱体浸渍-裂解法制备了SiBN陶瓷纤维增强SiBN陶瓷基复合材料,研究了复合材料的热膨胀特性、力学性能、断裂模式以及微观结构。结果表明:SiBN陶瓷纤维增强SiBN陶瓷基复合材料呈现明显的脆性断裂特征,复合材料的弯曲强度和拉伸强度分别为88.52 MPa和6.6 MPa,纤维的力学性能仍有待于提高。 Continuous fiber-reinforced nitride ceramic matrix composites are the main development direction of high-temperature wave-transparent materials, fiber is the pivotal issue which restrict the development of high-temperature wave-transparent composite materials, and SiBN ceramic fibers are a new kind of ceramic fibers which have excellent performances of high temperature resistance, wave transmission and mechanics. Polyborosilazane was used as ceramic precursor, and SiBN continuous fiber was used as reinforcement, SiBN fiber reinforced SiBN ceramic matrix composites were prepared by precursor infiltration-pyrolysis method. The thermal expansion properties, mechanical properties, fracture modes and microstructures of SiBN fiber reinforced SiBN ceramic matrix composites were investigated, and the preparation of new high-temperature wave-transparent ceramic matrix composites by precursor infiltration-pyrolysis was explored. The results show that the SiBN fiber reinforced SiBN ceramic matrix composites exhibits distinct brittle fracture characteristic, the bending strength and tensile strength of the composites are 88.52 MPa and 6.6 MPa respectively, which means the mechanical properties of the fiber still needs to be improved. 国家自然科学基金面上项目(51376189)
Fabrication and Tribological Behavior of Carbon Nanotube/Al Matrix Composites

JIANG Jin-long,DAI Jian-feng,YUAN Xiao-ming,WANG Hai-zhong,WEI Zhi-qiang,WANG Qin,

摩擦学学报 , 2007,
Abstract: Carbon nanotubes reinforced aluminum matrix composites were fabricated by powder metallurgy method. The influence of different carbon nanobube content on hardness, the friction and wear behavior under steady-state conditions of the composites were investigated. The worn surfaces of composites were observed by scanning electron microscope, and worn mechanism of composites was discussed. The results indicated that the Vikers hardness of composites increased first and then decreased with carbon nanotube content increasing. 2.0% addition by mass of carbon nanotubes to the aluminum matrix of caused increases in the Vikers hardness of about 80%. The friction coefficient of composites was low and decreased with increasing carbon nanotube content. On the other hand, wear rate of composites decreased firstly and then increased. For composite of 1.0% CNTs, the wear mechanism was characterized as abrasive wear and adhesive wear, while the delamination wear and surface fatigue were the mainly mechanism for composite of 2.0% CNTs.
Progress of a novel non-oxide Si-B-C-N ceramic and its matrix composites
Pengfei Zhang,Dechang Jia,Zhihua Yang,Xiaoming Duan,Yu Zhou
Journal of Advanced Ceramics , 2012, DOI: 10.1007/s40145-012-0017-x
Abstract: In the past twenty years, Si-B-C-N ceramic has attracted wide attention due to its special structure and outstanding properties. The ceramic generally has an amorphous or a nano-crystalline structure, and has excellent structural stability, oxidation resistance, creep resistance and high-temperature mechanical properties, etc. Thus, Si-B-C-N ceramic attracts many researchers and finds potential applications in transportation, aerocraft, energy, information, microelectronics and environment, etc. Much work has been carried out on its raw materials, preparation processes, structural evolution, phase equilibrium and high-temperature properties. In recent years, many researchers focus on its new preparation methods, the preparation of dense ceramic sample with large dimensions, ceramic matrix composites reinforced by carbon fiber or SiC whisker, or components with various applications. Research on Si-B-C-N ceramic will develop our insight into the relationship between structures and properties of ceramics, and will be helpful to the development of novel high-performance ceramics. This paper reviews the preparation processes, general microstructures, mechanical, chemical, electrical and optical properties, and potential applications of Si-B-C-N ceramic, as well as its matrix composites.
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.