Fabrication and Properties of Machinable AlN-BN Ceramic Nanocomposites

2006 ◽  
Vol 317-318 ◽  
pp. 637-640 ◽  
Author(s):  
Hai Yun Jin ◽  
Wen Wang ◽  
Ji Qiang Gao ◽  
Guan Jun Qiao ◽  
Zhi Hao Jin
Keyword(s):  
Mechanical Properties ◽  
Hot Pressing ◽  
Nitrogen Atmosphere ◽  
Weak Interface ◽  
X Ray Diffraction ◽  
Mechanical Mixing ◽  
X Ray ◽  
N2 Atmosphere ◽  
Nanocomposite Powders ◽  
Better Than

The AlN/h-BN nanocomposite powders were synthesized through the reaction of AlN powder, boric acid (H3BO3) and urea (CO(NH2)2) in a nitrogen atmosphere, and the machinable AlN/BN ceramic nanocomposite s were fabricated by hot-pressing in N2 atmosphere. The existing and distribution of h-BN phase are revealed by X-ray diffraction (XRD), TEM and SEM. For the existing of weak interface between h-BN and AlN grains, the machinability of AlN/BN composites is improved obviously. For the finer microstructures, the mechanical properties and the machinability of the composites with micrometer sized AlN coated with nano-sized BN are better than the AlN/h-BN composite of mechanical mixing type.

Machinability and Microstructure of SiC/h-BN Nano-Composites

2008 ◽  
Vol 569 ◽  
pp. 45-48
Author(s):  
Hai Yun Jin ◽  
Guan Jun Qiao ◽  
Zong Ren Peng ◽  
Ji Qiang Gao
Keyword(s):  
Fracture Strength ◽  
Nano Composites ◽  
Weak Interface ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sic Particles ◽  
N2 Atmosphere ◽  
The Matrix ◽  
Better Than

SiC particles coated with nano-BN were synthesized and the machinable SiC/BN ceramic nano-composites were fabricated by Plasma Active Sintering (PAS) in N2 atmosphere. The existing and distribution of h-BN phase were revealed by X-ray diffraction (XRD), and SEM. For the existing of weak interface between h-BN and SiC grains, the machinability of both SiC/BN micro-composites and nano-composites were improved obviously. Because the nano-sized h-BN crystals were homogeneously dispersed around the SiC grains of the matrix, the fracture strength of the nano-composites was better than the SiC/h-BN micro-composite.

Microstructure and Mechanical Properties of Fe-Cu-Ni Sinters Prepared by Ball Milling and Hot Pressing

2020 ◽  
Vol 405 ◽  
pp. 379-384
Author(s):  
Joanna Borowiecka-Jamrozek ◽  
Jan Lachowski
Keyword(s):  
Mechanical Properties ◽  
Hot Pressing ◽  
High Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Composition ◽  
Microstructure And Mechanical Properties ◽  
Static Tensile ◽  
Iron Based ◽  
Surface Observations

The main purpose of this work was to determine the effect of the powder composition on the microstructure and properties of iron-based sinters used as a matrix in diamond tools. The Fe-Cu-Ni sinters obtained from a mixture of ground powders were used for experiments. The influence of manufacturing process parameters on the microstructure and mechanical properties of sinters was investigated. Sintering was performed using hot-pressing technique in a graphite mould. The investigations of obtained sinters included: density, hardness, static tensile test, X-ray diffraction analysis, microstructure and fracture surface observations. The obtained results indicate that the produced sinters have good plasticity and relatively high hardness.

Stretching-Induced Orientation for Improving the Mechanical Properties of Electrospun Polyacrylonitrile Nanofiber Sheet

2008 ◽  
Vol 47-50 ◽  
pp. 1169-1172 ◽  
Author(s):  
Si Zhu Wu ◽  
Feng Zhang ◽  
Xiao Xiao Hou ◽  
Xiao Ping Yang
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanofibers ◽  
Molecular Orientation ◽  
High Performance ◽  
Carbon Composites ◽  
X Ray Diffraction ◽  
Fiber Alignment ◽  
X Ray ◽  
N2 Atmosphere ◽  
Potential Precursor

Partially aligned and oriented polyacrylonitrile(PAN)-based nanofibers were electrospun from PAN and CNTs/PAN in the solution of dimethylformamide(DMF) to manufacture the carbon nanofibers. The as-spun nanofibers were hot-stretched in a temperature controlled oven to enhance its crystallinity and molecular orientation. Therefore it were stabilized at 250 ( under a stress, and carbonized at 1000 ( in N2 atmosphere by fixing the length of the stabilized nanofiber to convert them into carbon nanofibers. With the hot-stretched process and with the content of CNTs, the mechanical properties will be enhanced correspondingly. The crystallinity of the stretched fibers confirmed by X-ray diffraction has also increased. For PAN nanofibers, the improved fiber alignment and crystallinity resulted in the increased mechanical properties, such as the modulus and tensile strength of the nanofibers. It was concluded that the hot-stretched nanofiber and the CNTs/PAN nanofibers can be used as a potential precursor to produce high-performance carbon composites.

Fabrication and Mechanical Properties of SiC/Cu Composites with Zn Addition by Hot Pressing Sintering

2013 ◽  
Vol 745-746 ◽  
pp. 700-705
Author(s):  
Huang Liu ◽  
Guo Qiang Luo ◽  
Pin Gan Chen ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
Mechanical Properties ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
High Volume ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zn Addition ◽  
Hot Pressing Sintering

SiC/Cu composites exhibit low density, low coefficient of thermal expansion and excellent mechanical properties. In this study, Zn of 2 wt. % was added as the sintering activator, and the high volume faction (60%) SiC/Cu composites was fabricated by hot pressing sintering technology. The phase composition and morphology of as-prepare samples were characterized by X-ray diffraction (XRD) system and scanning electron microscopy (SEM) equipped with an energy-dispersive spectroscopy (EDS) system. The as-prepared SiC/Cu composites were dense and uniform as well as void free. The results show that SiC/Cu composites can reach excellent mechanical properties of SiC/Cu composites. With the increase of sintering temperature, Vickers hardness and the bending strength of the samples increased obviously and the as-prepared SiC/Cu composites achieved a maximum Vickers hardness and bending strength respectively of 195MPa and 140MPa.

Preparation and Mechanical Properties of Rubber/Organoclay Nanocomposites

2011 ◽  
Vol 221 ◽  
pp. 200-204
Author(s):  
Guang Yi Lin ◽  
Ben Fa Gao ◽  
Chuan Sheng Wang
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Rubber Matrix ◽  
High Tensile Strength ◽  
X Ray Diffraction ◽  
Mechanical Mixing ◽  
X Ray ◽  
Mixing Method ◽  
Mooney Viscosity ◽  
Scanning Electron

The NR/SBR/oranoclay nancomposites were prepared by mechanical mixing method. The dispersion of the oranoclay in the rubber matrix was characterized by X-ray diffraction and scanning electron microscopy. And the effects of different filler and contents on the mechanical properties were investigated. The results showed that the particles of organoclay can be dispersed homogeneously in the rubber matrix. Compbination of carbon black and organoclay shows the synergistic effect which lead to high tensile strength. In addition, organoclay can decrease the Mooney viscosity which is useful for processing. The method is simple, which can be used industrially for use of organoclay in elastomer.

Study on Physical and Mechanical Properties of Cu/MoS2 Composites

2013 ◽  
Vol 575-576 ◽  
pp. 156-159
Author(s):  
Dou Qin Ma ◽  
Jing Pei Xie ◽  
Ji Wen Li ◽  
Ai Qin Wang ◽  
Wen Yan Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Diffraction Analysis ◽  
Electric Conductivity ◽  
Hot Pressing ◽  
Physical And Mechanical Properties ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vacuum Hot Pressing

Cu-3wt. %MoS2-7wt. %Mo and Cu-3wt. %MoS2 composites were prepared by repressing, re-sintering and vacuum hot pressing, respectively. Microstructures were characterized by optical metallographic microscope, EDS, SEM and X-ray diffraction analysis, respectively. The micro hardness, electric conductivity and density of samples were separately measured as well. Results show that the micro hardness of Cu-3wt. % MoS2-7wt. % Mo composites is about 33.3% higher than that of Cu-3wt. %MoS2 composites. The increase in micro hardness is attributed to the presence of Mo. The electric conductivity of Cu-3wt. %MoS2 and Cu-3wt. %MoS2-7wt. % Mo prepared by vacuum hot pressing were 80.6 % and 63.8% IACS, respectively, which is an increase compared with values of 80.2 % and 57.3% IACS of samples obtained by repressing and re-sintering.

DISPERSION AND MECHANICAL PROPERTIES OF CERIUM OXIDE FILLED INTO RUBBER COMPOSITES

2014 ◽  
Vol 87 (2) ◽  
pp. 340-347 ◽  
Author(s):  
Zhaogang Liu ◽  
Mei Li ◽  
Yanhong Hu ◽  
Hai Fu ◽  
Mitang Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cerium Oxide ◽  
Rubber Matrix ◽  
X Ray Diffraction ◽  
Small Particles ◽  
Rubber Composites ◽  
X Ray ◽  
Large Particles ◽  
Better Than ◽  
Properties Of Composites

ABSTRACT Rubber composites were synthesized by natural rubber filled with cerium oxide with different particle diameters. The dispersion morphology of cerium oxide in rubber matrix and the mechanical properties of composites were studied, and the contrast experiment of reinforcing rubber with cerium oxide was performed. The results showed that the small particles of cerium oxide had better disparity than the large particles of cerium oxide in NR. The mechanical properties of rubber filled with small particles of cerium oxide were better than those of rubber filled with large particles of cerium oxide. The crystalline rubber was measured by X-ray diffraction, which indicated that the CeO2 accelerated crystallization capacity and confined the rubber chain movement. The tensile strength of rubber was increased by this confinement.

Synthesis and Characterization of Polystyrene-Graphite Nanocomposites via Surface Raft-Mediated Polymerization

2012 ◽  
Vol 463-464 ◽  
pp. 527-532
Author(s):  
Hussein M. Etmimi ◽  
Ronald D. Sanderson
Keyword(s):  
Mechanical Properties ◽  
Miniemulsion Polymerization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reversible Addition ◽  
Raft Agent ◽  
Polymerization Method ◽  
Better Than

The synthesis of polystyrene/GO (PS-GO) nanocomposites using the reversible addition-fragmentation chain transfer (RAFT) mediated polymerization method is described. The GO was synthesized and immobilized with a RAFT agent to afford RAFT-functionalized GO nanosheets. The RAFT-immobilized GO was used for the synthesis of PS nanocomposites in a controlled manner using miniemulsion polymerization. The moelcular weight and dispersity of the PS in the nanocomposites depended on the amount of RAFT-grafted GO in the system, in accordance with the features of the RAFT-mediated polymerization. X-ray diffraction and transmission electron microscopy analyses revealed that the nanocomposites had exfoliated morphology, even at relatively high GO content. The thermal stability and mechanical properties of the PS-GO nanocomposites were better than those of the neat PS polymer. Furthermore, the mechanical properties of the nanocomposites were dependent on the RAFT grafted GO content.

Research on the Performance of the Cement Stabilized Gravel with Rubber Particles

2013 ◽  
Vol 838-841 ◽  
pp. 57-64 ◽  
Author(s):  
Ruo Chong Yang ◽  
Kai Li ◽  
Ji Peng Zhu ◽  
Shu Kai Ya ◽  
Dong Zheng
Keyword(s):  
Mechanical Properties ◽  
Frost Resistance ◽  
Primary Objective ◽  
Interface Bonding ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rubber Particles ◽  
Micro Morphology ◽  
Better Than ◽  
Sem Analyses

The primary objective of this paper was to study the mechanical properties and durability of the cement stabilized gravel which added rubber particles by using macroscopic and microscopic test. Through tests of compression, splitting and frost resistance, relationships between mechanical properties of samples and rubber particles content were studied. Scanning electron microscope (SEM) was applied to analyze the micro-morphology and elemental composition of samples, X-ray diffraction (XRD) was engaged to identify the product phases. The tests results showed that compressive strength of mixtures decreased with the rubber particles content increasing and the early strength effect was obvious, splitting strength decreased slightly. It also indicated that the addition of rubber particles can improve the frost resistance of the mixtures. As a result, the frozen stability coefficient (K) of samples was improved from 0.89 to 0.97. XRD and SEM analyses showed that calcium silicate hydrate (CSH) was resultant and the interface bonding between sand and CSH was better than rubber particles and CSH, which the latter had interface cracks.

Effect of Annealing Temperature on Austenite Stability of a δ-TRIP Steel

2019 ◽  
Vol 818 ◽  
pp. 82-86
Author(s):  
Xin Xu ◽  
Ren Dong Liu ◽  
Bao Yu Xu ◽  
Hong Liang Yi ◽  
Guo Dong Wang
Keyword(s):  
Mechanical Properties ◽  
Trip Steel ◽  
Retained Austenite ◽  
Annealing Temperature ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Austenite Stability ◽  
Poor Stability ◽  
Better Than

In this work, a novel type of δ-TRIP steel was designed, and the content and stability of retained austenite in δ-TRIP specimens under different annealing processes were detected and studied, respectively. The volume fraction of austenite was determined by X-ray diffraction (XRD). The microstructure and mechanical properties were analyzed systematically. The results show that a complex microstructure composed of three phases (ferrite, bainite and retained austenite) was obtained in the δ-TRIP steel. With the increasing of annealing temperature, both retained austenite and bainite content in the specimen increased, while the carbon content in retained austenite decreased, leading to a poor stability for retained austenite. Both tensile and yield strength improved with the increasing of annealing temperature, while the elongation reduced. The feature of retained austenite led to an excellent combination of ductility and strength, which was better than traditional TRIP steel.

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