Toward highly compressible graphene aerogels of enhanced mechanical performance with polymer

RSC Advances ◽  
2016 ◽  
Vol 6 (49) ◽  
pp. 43007-43015 ◽  
Author(s):  
Hao Lu ◽  
Chenwei Li ◽  
Baoqing Zhang ◽  
Xin Qiao ◽  
Chen-Yang Liu
Keyword(s):  
Mechanical Performance ◽  
Casting Process ◽  
Freeze Casting ◽  
Binding Effect ◽  
Graphene Aerogels

The highly compressive durable graphene aerogels with enhanced strength was prepared by combining the freeze-casting process with the binding effect of polymer.

scholarly journals Effect of flake size on the mechanical properties of graphene aerogels prepared by freeze casting

RSC Advances ◽  
2017 ◽  
Vol 7 (53) ◽  
pp. 33600-33605 ◽  
Author(s):  
Weiwei Gao ◽  
Nifang Zhao ◽  
Weiquan Yao ◽  
Zhen Xu ◽  
Hao Bai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fatigue Resistance ◽  
Mechanical Performance ◽  
Freeze Casting ◽  
Graphene Flake ◽  
Graphene Aerogels

Graphene flake size has a profound effect on the mechanical performance of the assembled graphene aerogels, particularly their strength, modulus and fatigue resistance under compression.

scholarly journals Variation of Mechanical Characteristics of Polyurethane Foam: Effect of Test Method

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2672 ◽  
Author(s):  
Ki-Beom Park ◽  
Hee-Tae Kim ◽  
Nam-Yong Her ◽  
Jae-Myung Lee
Keyword(s):  
Polyurethane Foam ◽  
Evaluation Method ◽  
Mechanical Performance ◽  
Cell Structure ◽  
Extreme Environments ◽  
Evaluation Criteria ◽  
Test Method ◽  
Material Behavior ◽  
Insulation Material ◽  
Binding Effect

Polyurethane foam (PUF), a representative insulation material, not only prevents heat conduction but can also support a load. Particular interest in rigid PUF proliferated over the past several years in fields where extreme environments are applied. A closed-cell structure which forms the interior of rigid PUF serves to maximize the utilization of these polymeric foams. Rigid PUF is more sensitive to external conditions such as temperature or restraint than other structural materials such as steel. Depending on the market trends in which utilization of a cryogenic environment is expanding, the tendency of material behavior resulting from the binding effect also needs to be investigated. However, most conventional compression test method standards applicable to rigid PUF do not adequately reflect the restraints. Therefore, this study proposes a method for evaluating the mechanical performance of materials in a more reliable manner than that of conventional tests. Experimental observation and analysis validated this compression evaluation method in which constraints are considered. Consequently, the compressive strength of rigid PUF compared to the results of the conventional test showed a difference of up to 0.47 MPa (approximately 23%) at cryogenic temperatures. This result suggests that there are important factors to consider when assessing performance from a material perspective in an environment where rigid PUF insulation is utilized. It is believed that the test methods newly proposed in this study will provide an experimental framework that can be applied to the evaluation criteria of material properties and reflected in structural design.

Combined multi-nozzle deposition and freeze casting process to superimpose two porous networks for hierarchical three-dimensional microenvironment

2014 ◽  
Vol 6 (1) ◽  
pp. 015007 ◽  
Author(s):  
Jessica E Snyder ◽  
Philipp M Hunger ◽  
Chengyang Wang ◽  
Qudus Hamid ◽  
Ulrike G K Wegst ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Casting Process ◽  
Freeze Casting ◽  
Porous Networks

Preparation, Microstructure and Properties of ZrO2 Gradient Porous Ceramics by Freeze-Casting Process

2015 ◽  
Vol 816 ◽  
pp. 226-230 ◽  
Author(s):  
Tao Tao Ai
Keyword(s):  
Electron Microscopy ◽  
Compressive Strength ◽  
Porous Structure ◽  
Cross Section ◽  
Lamellar Structure ◽  
Sintering Temperature ◽  
Casting Process ◽  
Porous Ceramics ◽  
Freeze Casting ◽  
Scanning Electron

The ZrO2gradient porous ceramics were prepared by a novel freeze-casting process. The porous structure of the ZrO2ceramics was investigated by scanning electron microscopy (SEM). And the porosity and compressive strength were also measured. Experimental results indicated that the porous structure of the specimens was remarkably affected by the sintering temperature. The dendritic pores were obtained after sintered at 1300 °C. The porosity and compressive strength of the specimen were 56.79% and 4.37 MPa, respectively. As the sintering temperature reached to 1500 °C, a lamellar structure was obtained on the cross-section of the specimen. Meanwhile, the porosity decreased to 26.77% and the compressive strength increased to 8.26 MPa. The ceramics can be divided subsequently into three distinctive zones along the solidification direction, i.e. lamellar zone, transition zone and cellular zone.

A Comparison of Deep Drawing and Ironing of Metal Alloy Strip Produced Conventionally and Non-Conventionally via Semi Solid Material Processing

2008 ◽  
Vol 141-143 ◽  
pp. 49-54 ◽  
Author(s):  
Antonio de Pádua Lima Filho ◽  
Márcio Iuji Yamasaki ◽  
Leandro Akita Ono ◽  
Lourenço Nampo ◽  
Alcides Padilha
Keyword(s):  
Deep Drawing ◽  
Mechanical Performance ◽  
Phase Segregation ◽  
Casting Process ◽  
Solid Material ◽  
Thin Strip ◽  
Hypoeutectic Alloy ◽  
Drawing Ratio ◽  
Cooling Slope ◽  
Semi Solid

A semi solid thin strip continuous casting process was used to obtain 50%wt Pb/50%wtSn strip by single and twin roll processing at speed of 15 m/min. A 50%wt Pb/50%wtSn plate ingot was also cast for rolling conventionally into strips of 1.4 mm thickness and 45 mm width for comparison with those achieved non-conventionally. This hypoeutectic alloy has a solidification interval and fusion temperature of approximately 31°C and 215°C respectively. The casting alloy temperature was around 280°C as measured by a type K immersion thermocouple prior to pouring into a tundish designed to maintain a constant melt flow on the cooling slope during semi solid material production. A nozzle with a weir ensures that the semi solid material is dragged smoothly by the lower roll, producing strip with minimum contamination of slag/oxide. The temperatures of the cooling slope and the lower roll were also monitored using K type thermocouples. The coiled semi solid strip, which has a thickness of 1.5 mm and 45 mm width, was rolled conventionally in order to obtain 1.2 mm thick strip. The coiled thixorolled strip had a thickness of 1.2 mm and achieved practically the same width as the conventional strips. Blanks of 40 mm diameter were cut from the strips in a mechanical press, ready for deep drawing and ironing for mechanical characterization. All the strips achieved from non-conventional processing had the same mechanical performance as those achieved conventionally. The limiting drawing ratio (LDR) achieved was approximately 2.0 for all strips. Microscopy examination was made in order to observe phase segregation during processing.

Production of fire clay porous structure with no aligned macro porosity from water-based slurry by freeze casting process: A new approach

2016 ◽  
Vol 42 (7) ◽  
pp. 9278-9282 ◽  
Author(s):  
Marcelo Strozi Cilla ◽  
Juliana de Melo Cartaxo ◽  
Romualdo Rodrigues Menezes ◽  
Lisiane Navarro deLima Santana ◽  
Gelmires de Araujo Neves
Keyword(s):  
Porous Structure ◽  
Casting Process ◽  
Freeze Casting ◽  
New Approach ◽  
Water Based ◽  
Fire Clay

scholarly journals Freeze casting process for the generation of graded porosity in Al2O3 ceramics

Cerâmica ◽  
2020 ◽  
Vol 66 (377) ◽  
pp. 65-73
Author(s):  
E. Pagano ◽  
A. S. A. Chinelatto ◽  
A. L. Chinelatto
Keyword(s):  
Fracture Mode ◽  
Pore Formation ◽  
Mechanical Response ◽  
Casting Process ◽  
Ceramic Materials ◽  
Processing Route ◽  
Uniaxial Compression Test ◽  
Freeze Casting ◽  
Casting Method ◽  
Pore Characteristics

Abstract Alumina ceramic materials with graded functional porosity were prepared by the freeze casting method and characterized. The effects of processing route parameters on the pore formation were studied. Pore characteristics were investigated concerning morphology and distribution in the ceramic matrix. The mercury intrusion method was used to evaluate the porosity. Mechanical properties, as well as the fracture mode, were investigated by the uniaxial compression test. Scanning electron microscopy was used to analyze and correlate the created interface between the layers with the mechanical response. The results suggested that the porosity obtained in all samples was similar, even with varying parameters (different suspension solidification configurations). When evaluating the mechanical behavior, these distinct parameters showed drastic differences in compressive strength and failure mode. This was due to the formation of interfaces between the layers of different porosities, according to the solidification configuration. The interfaces modified the fracture mode, changing from a longitudinal-directed to an interface-directed fracture. The pore microstructure and morphology indicated highly connected pore channels.

Preparation Technology of Al-Fe-V-Si Heat-Resistant Aluminum Alloy with Single Roller Spinning Method

2013 ◽  
Vol 433-435 ◽  
pp. 2081-2084
Author(s):  
Jin Jun Tang ◽  
Zhao Hui Gong ◽  
Liang Jun Fei ◽  
Xiu Rong Zhu ◽  
Hong Xia Shi
Keyword(s):  
Aluminum Alloy ◽  
Mechanical Performance ◽  
Temperature Stability ◽  
High Strength ◽  
Casting Process ◽  
Atomic Fraction ◽  
High Temperature Stability ◽  
Phase Coarsening ◽  
Cooling Speed ◽  
Precipitated Phases

High strength aluminum alloy is mainly traditional alloy hypoeutectic composition, containing the solid solubility of alloy elements atomic fraction is greater than 2, and reached the alloy trengthening effect by the precipitation of intermetallic compounds in the process of aging. But in more than 150°C, the precipitated phases coarsening, the material performance dramatically, thus limiting its use scope. In the preparation process, the planar flow casting process will melt thrown by 35-80um thick slices with, because the cooling speed can reach 105K/s the process of melt, so the microstructure is very fine, after extrusion. Grain size of about 1um, precipitates spherical and uniform distribution, the size of about 50nm, Al12(Fe,V)3Si phase coarsening rate is low, so the alloy has comprehensive mechanical performance and excellent high temperature stability.

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