Mechanical Properties and Chemical Characterization of Mortars with Halloysite Nanoclay after Exposure to Elevated Temperatures

2019 ◽  
Vol 8 (3) ◽  
pp. 20190028 ◽  
Author(s):  
Nima Farzadnia
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Chemical Characterization

Enhancing the Thermal and Mechanical Characteristics of Polyvinyl Alcohol (PVA)-Hemp Protein Particles (HPP) Composites

2021 ◽  
Vol 36 (2) ◽  
pp. 137-143
Author(s):  
S. A. Awad
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Composite Films ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Solution Casting Method ◽  
Protein Particles

Abstract This paper aims to describe the thermal, mechanical, and surface properties of a PVA/HPP blend whereby the film was prepared using a solution casting method. The improvements in thermal and mechanical properties of HPP-based PVA composites were investigated. The characterization of pure PVA and PVA composite films included tensile tests, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results of TGA and DSC indicated that the addition of HPP increased the thermal decomposition temperature of the composites. Mechanical properties are significantly improved in PVA/HPP composites. The thermal stability of the PVA composite increased with the increase of HPP filler content. The tensile strength increased from 15.74 ± 0.72 MPa to 27.54 ± 0.45 MPa and the Young’s modulus increased from 282.51 ± 20.56 MPa to 988.69 ± 42.64 MPa for the 12 wt% HPP doped sample. Dynamic mechanical analysis (DMA) revealed that at elevated temperatures, enhanced mechanical properties because of the presence of HPP was even more noticeable. Morphological observations displayed no signs of agglomeration of HPP fillers even in composites with high HPP loading.

scholarly journals Analysis of the properties of a Cu-Al2-O3 sintered system based on ultra fine and nanocomposite powders

2007 ◽  
Vol 39 (2) ◽  
pp. 145-152 ◽  
Author(s):  
Z. Andjic ◽  
M. Korac ◽  
Z. Kamberovic ◽  
A. Vujovic ◽  
M. Tasic
Keyword(s):  
Mechanical Properties ◽  
Chemical Method ◽  
Elevated Temperatures ◽  
Hydrogen Atmosphere ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Composite Powders ◽  
Nanocomposite Powders ◽  
Final Composition

In this paper synthesis of a composite based on Cu-Al2O3 by a thermo-chemical method is shown along with a comparative analysis of the properties of the obtained nanocomposite sintered samples, which are characterized by a good combination of electric-mechanical properties, suitable for work at elevated temperatures. Ultra fine and nanocrystal powder Cu-Al2O3 is obtained by a chemical method, starting from water solutions of nitrates up to achieving the requested composition with 3 and 5% of Al2O3. Synthesis of composite powders has been developed through several stages: drying by spraying, oxidation of the obtained powder of precursor and then reduction by hydrogen until the final composition of nanocomposite powder is achieved. After characterization of the obtained powders, which comprised examination by the Scanning Electronic Microscopy (SEM) method and X-ray-structure analysis (RDA), the powders were compacted with compacting pressure of 500 MPa. Sintering of the obtained samples was performed in the hydrogen atmosphere in isothermal conditions at temperatures of 800 and 900oC for 30, 60, 90 and 120 minutes. Characterization of the obtained Cu-Al2O3 of the nanocomposite sintered system comprised examination of microstructure by the Scanning Electronic Microscopy (SEM), as well as examining of electric mechanical properties. The obtained results show a homogenous distribution of dispersoides in the structure, as well as good mechanical and electric properties. .

scholarly journals Mechanical properties of mortar produced with the replacement of natural sand by scheelite residue

Cerâmica ◽  
2019 ◽  
Vol 65 (375) ◽  
pp. 443-451 ◽  
Author(s):  
B. A. Medeiros ◽  
G. A. Neves ◽  
N. P. Barbosa ◽  
R. R. Menezes ◽  
H. C. Ferreira
Keyword(s):  
Mechanical Properties ◽  
Chemical Characterization ◽  
Mechanical Tests ◽  
Cement Type ◽  
Natural Sand ◽  
Physical And Chemical Characterization ◽  
Water Absorption Test ◽  
Treatment And Disposal ◽  
Physical And Chemical

Abstract The residue generated by industrial activities represents a cost, since the generators are responsible for its management, transportation, treatment and disposal. Rio Grande do Norte State in Brazil is the greatest producer of scheelite residue. The aim of this research was to characterize this mining residue, identify its similarity with natural sand and produce a coating mortar with it. In the composition of mortar, a Brazilian Portland cement type CPII-F32 and an industrialized calcium hydroxide as a binder were used. Laser granulometry, bulk and relative density, EDX, XRD and thermal analysis were done to obtain a physical and chemical characterization of the residue. Mechanical tests (tensile bond strength and compressive strength), SEM and water absorption test were done to analyze the behavior of mortar. All tests confirmed that mechanical properties were according to standards for tile mortar.

Deposition and Properties of Doped Diamondlike Carbon Films Produced by Dual-Source Vacuum Arc Plasma Immersion

1996 ◽  
Vol 438 ◽  
Author(s):  
O. R. Monteiro ◽  
M. P. Delplancke-Ogletree ◽  
I. G. Brown ◽  
J. W. Ager
Keyword(s):  
Mechanical Properties ◽  
Chemical Characterization ◽  
Carbon Films ◽  
Vacuum Arc ◽  
Internal Stresses ◽  
Dopant Content ◽  
Dual Source ◽  
High Level ◽  
Thermal Stability Of

AbstractDiamond-like carbon films with mechanical properties approaching those of diamond have been consistently produced by cathodic vacuum arc based techniques. These films have been successfully used in applications where enhanced hardness and wear resistance are required Such DLC films have two major drawbacks that prevent their application in other areas: a high level of internal stresses, which promotes failure by spallation of thick films; and the loss of mechanical properties at temperatures higher than 300°C. In this paper we describe the effect of doping elements on the room-temperature mechanical properties and on the thermal stability of DLC films upon annealing in air. The effect of the presence of W and Ti was investigated and compared to pure DLC. The films were produced by dual-source metal plasma immersion ion implantation and deposition with magnetic filtering to remove macroparticles from the plasma; dopant content was controlled by varying the relative pulse duration of the two plasma sources. Microstructural and chemical characterization of the films are presented.

scholarly journals Mechanical and Microstructural Characterization of Quarry Rock Dust Incorporated Steel Fiber Reinforced Geopolymer Concrete and Residual Properties after Exposure to Elevated Temperatures

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6890
Author(s):  
Muhammad Ibraheem ◽  
Faheem Butt ◽  
Rana Muhammad Waqas ◽  
Khadim Hussain ◽  
Rana Faisal Tufail ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Compressive Strength ◽  
Fly Ash ◽  
Mechanical Strength ◽  
Elevated Temperatures ◽  
Strength Properties ◽  
Steel Fibers ◽  
Geopolymer Concrete

The purpose of this research is to study the effects of quarry rock dust (QRD) and steel fibers (SF) inclusion on the fresh, mechanical, and microstructural properties of fly ash (FA) and ground granulated blast furnace slag (SG)-based geopolymer concrete (GPC) exposed to elevated temperatures. Such types of ternary mixes were prepared by blending waste materials from different industries, including QRD, SG, and FA, with alkaline activator solutions. The multiphysical models show that the inclusion of steel fibers and binders can enhance the mechanical properties of GPC. In this study, a total of 18 different mix proportions were designed with different proportions of QRD (0%, 5%, 10%, 15%, and 20%) and steel fibers (0.75% and 1.5%). The slag was replaced by different proportions of QRD in fly ash, and SG-based GPC mixes to study the effect of QRD incorporation. The mechanical properties of specimens, i.e., compressive strength, splitting tensile strength, and flexural strength, were determined by testing cubes, cylinders, and prisms, respectively, at different ages (7, 28, and 56 days). The specimens were also heated up to 800 °C to evaluate the resistance of specimens to elevated temperature in terms of residual compressive strength and weight loss. The test results showed that the mechanical strength of GPC mixes (without steel fibers) increased by 6–11%, with an increase in QRD content up to 15% at the age of 28 days. In contrast, more than 15% of QRD contents resulted in decreasing the mechanical strength properties. Incorporating steel fibers in a fraction of 0.75% by volume increased the compressive, tensile, and flexural strength of GPC mixes by 15%, 23%, and 34%, respectively. However, further addition of steel fibers at 1.5% by volume lowered the mechanical strength properties. The optimal mixture of QRD incorporated FA-SG-based GPC (QFS-GPC) was observed with 15% QRD and 0.75% steel fibers contents considering the performance in workability and mechanical properties. The results also showed that under elevated temperatures up to 800 °C, the weight loss of QFS-GPC specimens persistently increased with a consistent decrease in the residual compressive strength for increasing QRD content and temperature. Furthermore, the microstructure characterization of QRD blended GPC mixes were also carried out by performing scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS).

Chemical characterization of a degradable polymeric bone adhesive containing hydrolysable fillers and interpretation of anomalous mechanical properties

2009 ◽  
Vol 5 (6) ◽  
pp. 2072-2083 ◽  
Author(s):  
Anne M. Young ◽  
Sze Man Ho ◽  
Ensanya A. Abou Neel ◽  
Ifty Ahmed ◽  
Jake E. Barralet ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Characterization

Processing and Characterization of Al2O3-YAG Composite

2012 ◽  
Vol 727-728 ◽  
pp. 1334-1339
Author(s):  
E.S. Lima ◽  
Luis Henrique Leme Louro ◽  
José Brant de Campos ◽  
R.R. de Avillez ◽  
Sérgio Neves Monteiro ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Transition ◽  
Elevated Temperatures ◽  
Eutectic Reaction ◽  
Ceramic Matrix ◽  
Oxide Ceramics ◽  
High Temperature Mechanical Properties ◽  
Wide Range ◽  
Potential Use

Oxide ceramics show better oxidation resistance at high temperatures than other ceramics; however they are more susceptible to plastic deformation at elevated temperatures [. If their high temperature mechanical properties could be improved, they would be expected to open a wide range of applications as structural material [2, 3]. Several studies have revealed [4, 5] the potential use of YAG oxides as reinforcing component oxide in a ceramic matrix. Both YAG and Al2O3 have similar thermal expansion coefficient and they are chemically stable because of their low O2 vapor pressure. In addition, there is no solid state phase transition as the temperature rises, but the eutectic reaction at 1826°C with Al2O3 molar concentration of 81.5% and 18.5% for Y2O3 which enable a fusion processing, turning the Al2O3-YAG composites very attractive. This eutectic reaction is possible in the restrictive composition from 18.5 to 20.5 mol% Y2O3 [6].

scholarly journals Microstructure and Mechanical Properties of Precipitate Strengthened High Entropy Alloy Al10Co25Cr8Fe15Ni36Ti6 with Additions of Hafnium and Molybdenum

Entropy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 169 ◽  
Author(s):  
Sebastian Haas ◽  
Anna M. Manzoni ◽  
Fabian Krieg ◽  
Uwe Glatzel
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Base Alloy ◽  
Tensile Tests ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Positive Effects ◽  
High Temperature Materials ◽  
Equiatomic Alloy

High entropy or compositionally complex alloys provide opportunities for optimization towards new high-temperature materials. Improvements in the equiatomic alloy Al17Co17Cr17Cu17Fe17Ni17 (at.%) led to the base alloy for this work with the chemical composition Al10Co25Cr8Fe15Ni36Ti6 (at.%). Characterization of the beneficial particle-strengthened microstructure by scanning electron microscopy (SEM) and observation of good mechanical properties at elevated temperatures arose the need of accomplishing further optimization steps. For this purpose, the refractory metals hafnium and molybdenum were added in small amounts (0.5 and 1.0 at.% respectively) because of their well-known positive effects on mechanical properties of Ni-based superalloys. By correlation of microstructural examinations using SEM with tensile tests in the temperature range of room temperature up to 900 °C, conclusions could be drawn for further optimization steps.

Characterization of grain boundary phases in Si3N4 sintered using Y-Si-Al-O-N additives

1990 ◽  
Vol 48 (4) ◽  
pp. 1070-1071
Author(s):  
C. Koehler ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Elevated Temperatures ◽  
Secondary Phases ◽  
Amorphous Phases ◽  
High Temperature Mechanical Properties

The usefulness of silicon nitride as a high temperature ceramic can be limited by the presence of amorphous phases at the grain boundaries. Dense silicon nitride ceramics are produced using pressureless sintering of Si3N4 with Y-Si-Al-O-N additives. When these additives are left as a glassy phase at the grain boundaries and triple grain junctions, the mechanical properties at elevated temperatures are weakened due to these low viscous glasses. Post-sintering heat treatments and close compositional control can be effective in transforming the glass into crystalline phases at the grain boundaries thereby increasing the refractoriness.To optimize high temperature mechanical properties, processing must be controlled not only to fully crystallize the grain boundaries but also to avoid certain unstable secondary phases whose oxidation leads to large molar volume changes which causes possible cracking. Transmisssion electron microscopy and x-ray microanalysis (EDS) are significant methods to characterize the amorphous grain boundary pockets and to identify the crystalline grain boundary phases.

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