Mechanical Characteristics of Tunnel Concrete Lining Made with Dredged Sediment Subjected to High Temperatures

2021 ◽  
pp. 341-347
Author(s):  
Fatiha Kazi Aoual-Benslafa ◽  
Kawther Touhami
Keyword(s):  
High Temperatures ◽  
Mechanical Characteristics ◽  
Concrete Lining ◽  
Dredged Sediment

Investigation of the Properties of Alumina-Zirconia Ceramics

2014 ◽  
Vol 1040 ◽  
pp. 245-249
Author(s):  
Aleksander S. Ivashutenko ◽  
Alexandr V. Kabyshev ◽  
Nikita Martyushev ◽  
Igor G. Vidayev
Keyword(s):  
Dielectric Constant ◽  
Electric Conductivity ◽  
High Temperatures ◽  
Electrostatic Field ◽  
Mechanical Characteristics ◽  
Ferroelectric Properties ◽  
Dissipation Factor ◽  
Zirconia Ceramics ◽  
Measurement Results ◽  
Dielectric Dissipation Factor

The article focuses on the investigation of the properties of alumina-zirconia ceramics possessing high mechanical characteristics and good conductivity at high temperatures. Measurement results of the dielectric dissipation factor, dielectric constant, electric conductivity when using direct and alternating current for the ceramics samples of 80%(ZrO2-3%Y2O3)-20% Al2O3 composition are presented in the paper. Measurements were conducted simultaneously in the electrostatic field in vacuum while heating the samples to the temperatures ranging from 300 to 1700K. Investigations showed that alumina-zirconia ceramics at high temperatures obtains ferroelectric properties not typical of these structures.

The Effect of the Deformation Method of the Billets on Mechanical Properties of Molybdenum Bars and Wire

2020 ◽  
Vol 864 ◽  
pp. 204-210
Author(s):  
Sergey Gorbatyuk ◽  
Dmitry Efremov ◽  
Sergei Albul ◽  
Natalya Kirillova
Keyword(s):  
Mechanical Properties ◽  
Comparative Analysis ◽  
High Temperatures ◽  
Rolling Mill ◽  
Mechanical Characteristics ◽  
New Technology ◽  
Deformation Resistance ◽  
Helical Rolling ◽  
Deformation Method ◽  
High Deformation

A procedure has been developed for calculating the geometric, kinematic and energy-power parameters of helical rolling, which allows a comparative analysis of the processes carried out in stands of various designs. Based on the results of this analysis, a helical rolling mill was designed and manufactured which allows to roll materials with high deformation resistance at high temperatures. The results of the study of the mechanical characteristics of molybdenum bars and wires made by new technology are presented.

TRENDS IN THE DEVELOPMENT OF CAST MAGNESIUM ALLOYS WITH AN INCREASED IGNITION TEMPERATURE (review)

2021 ◽  
pp. 3-9
Author(s):  
A.A. Leonov ◽  
◽  
N.V. Trofimov ◽  
V.A. Duyunova ◽  
Z.P. Uridiya ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloys ◽  
High Temperatures ◽  
Fire Resistance ◽  
Ignition Temperature ◽  
Mechanical Characteristics ◽  
Chemical Characteristics ◽  
Increased Temperature ◽  
Cast Magnesium Alloys ◽  
Cast Magnesium

Trends in the development of cast magnesium alloys with increased temperature, ignition and fire resistance are presented. The main world companies and institutions - developers of casting magnesium alloys are presented. The developed alloys are considered, indicating their chemical characteristics, mechanical characteristics at high and high temperatures and corrosion resistance, as well as the use of materials and design aspects of industry. The presented magnesium alloys with an increased ignition temperature allow expanding the scope of their use.

Integration of Port Dredged Sediments Into the Production of Fired Clay Bricks

2019 ◽  
Vol 45 (4) ◽  
pp. 428-440
Author(s):  
Ikram Frar ◽  
Houdaifa Bakkali ◽  
Mohammed Ammari ◽  
Laïla Ben Allal
Keyword(s):  
Compressive Strength ◽  
Substitution Rate ◽  
Mechanical Characteristics ◽  
Raw Materials ◽  
Partial Substitution ◽  
Dredged Sediment ◽  
Natural Clay ◽  
Dredged Sediments ◽  
Clay Bricks ◽  
Fired Bricks

Bricks manufactured, based on dredged sediments extracted from Tangier and Larache ports in Morocco were investigated. Chemical, physical, geotechnical, mineralogical and environmental characterizations studies of ports dredged sediments were performed. Partial substitution of natural clay by dredged sediments was achieved with different substitution rates by weight (20%, 40%, 50%, 60% and 70%) to manufacture brick samples at the laboratory scale. The compressive strength was the factor determining the optimal substitution rate of the natural clay. Compressive strength values of fired bricks with different rates of sediments incorporated show that the manufactured bricks have mechanical characteristics relatively close to natural clay until 60% substitution for Larache port dredged sediment (SL) and until 50% for Tangier port dredged sediment (ST). The results in this study confirm that dredged sediments from the ports of Tangier and Larache can be used as an alternative raw materials resource for the manufacturing of fired bricks.

Changes in physical and mechanical properties of limestone and marble after exposure to different high temperatures

2019 ◽  
Vol 53 (3) ◽  
pp. 378-385
Author(s):  
Weiqiang Zhang ◽  
Chenchen Xu ◽  
Jishi Geng
Keyword(s):  
Mechanical Properties ◽  
Thermal Diffusivity ◽  
High Temperatures ◽  
Mechanical Characteristics ◽  
Heating Temperature ◽  
Physical And Mechanical Properties ◽  
P Wave ◽  
High Temperature Treatment ◽  
Peak Strain ◽  
Physical And Mechanical Characteristics

Under or after high-temperature treatment, the physical and mechanical characteristics of limestone and marble change significantly. This study seeks to understand the effect of high temperatures on physical and mechanical properties (such as density, porosity, permeability, P-wave velocity, thermal diffusivity, elastic modulus, uniaxial compressive strength, peak strain and Poisson's ratio) of limestone and marble. The results indicate that, from room temperature to 300°C, most of the physical and mechanical indices of limestone and marble change relatively little, except for thermal diffusivity. Above 300°C (especially at 400–600°C), physical and mechanical characteristics change significantly, corresponding to the changes to minerals between 400 and 600°C. These results confirm the important link between physical and mechanical properties and heating temperature, and can provide the basis of theory and reference for related engineering.

Study on Al-Si Alloys Properties Enhancement

2015 ◽  
Vol 754-755 ◽  
pp. 634-638
Author(s):  
Dragoş Cristian Achiţei ◽  
Petrică Vizureanu ◽  
Mirabela Georgiana Minciună ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Ioan Gabriel Sandu
Keyword(s):  
High Temperatures ◽  
Mechanical Characteristics ◽  
Heat Treatments ◽  
Temperature Curve ◽  
Mg Alloys ◽  
Cu Alloys ◽  
Intermediate Phases ◽  
Successive Heating ◽  
Structural Hardening

The paper presents a study about aluminum alloy, allied with Si, Cu, Mn, Mg. The Al-Si-Cu-Mg alloys for foundry are used for parts strongly required and which work at high temperatures, due to their good wear resistance. The industrial Al-Cu alloys contain 12 % cooper, are hipo-eutectic and may be for foundry or deformable. By alloying with magnesium, the Al-Cu alloys become with remarkable properties of resistance and plastic deformation processing. The improvement of mechanical characteristics for Al-Si alloys is realized with metals which forms the intermediate phases with silicon or aluminum, with variable solubility in solid state and which permits the structural hardening by heat treatments (quenching and ageing). From the analysis of dilatogramms, grouped for each sample, with the specific initial length, subjected to successive heating, from ambiance temperature up to 500°C, it is found that, with the appearance of ageing phenomena, on the samples aren’t significant modifications for elongation (few microns), only different may be the form of elongation-temperature curve. This analysis permits the determination of experimental data, regarding the behavior of Al-Si alloy subjected to heat treatments and repeated warming. Therefore, the Al-Si-Cu-Mg alloys, for foundry, are used for manufacture the parts strong required and which work at high temperatures, like pistons for engines with internal burn, parts for machines and reinforcements construction, due to their high usage resistance.

Evaluation of Mechanical Properties and Various Pile-Up of Plate-Type Polymer Using Nanoindenter

2011 ◽  
Vol 264-265 ◽  
pp. 675-680
Author(s):  
Y.N. Joung ◽  
Chung Gil Kang ◽  
S.M. Lee
Keyword(s):  
Mechanical Properties ◽  
Molecular Electronics ◽  
High Temperatures ◽  
Room Temperature ◽  
Mechanical Characteristics ◽  
Structure And Properties ◽  
Pile Up ◽  
Extreme Variation ◽  
Quantitative Properties ◽  
Plate Type

For producing high-quality components through a nanoimprint lithographic (NIL) process, it is important to measure quantitative properties about the behavior of polymers with regard to thermal-nano variation. NanoScale indents can be used as cells for molecular electronics and drug delivery and slots for integration into nanodevices; they can be used to detect defects for tailoring the structure and properties. This study evaluates the mechanical characteristics of polymers, such as Polymethylmetacrylate (PMMA) and COP (Cyclo-olefin Polymer), at high temperatures for the manufacture of nano/micro-sized polymers through thermal nanoindentation at high temperatures. At high temperatures, the mechanical properties of polymers exhibit extreme variation. When a polymer is heated, it becomes softer than at room temperature. In this regard, it is especially important to study the mechanical properties of polymers at high temperatures.

scholarly journals Influence of heating to high temperatures on mechanical properties of boride-based refractory materials

2021 ◽  
Vol 2 (1(58)) ◽  
pp. 21-25
Author(s):  
Anastasiia Lokatkina ◽  
Tetiana Prikhna ◽  
Viktor Moshchil ◽  
Pavlo Barvitskyi ◽  
Oleksandra Borimsky ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperatures ◽  
Mechanical Characteristics ◽  
Aerospace Industry ◽  
Initial Mixture ◽  
Refractory Materials ◽  
Melting Temperatures ◽  
Before And After ◽  
Sintered Materials

The object of research is HfB2, ZrB2 and ceramics composition HfB2-30 % SiC and ZrB2-20 % SiC, ZrB2-20 % SiC-4 % Si3N4 obtained under high pressure, their mechanical characteristics before and after heating to high temperatures and temperatures of beginning of melting. The research was conducted in order to create new effective refractory materials for use in the aerospace industry. Therefore, the melting temperatures of sintered materials and the effect of heating on their mechanical properties were also studied. Additives (ZrB2-20 % SiC and HfB2-30 % SiC) although led to a decrease in specific gravity. But increased hardness (by 17 % and 46 % in the case of ZrB2 and HfB2, respectively) and fracture toughness (by 40 % and 21 % in the case of ZrB2 and HfB2, respectively). However, significantly reduced the onset of melting temperature in vacuum to 2150–2160 °C. Materials sintered from ZrB2 and HfB2 was not melted after heating to 2970 °C. After heating to a melting point of 2150–2160 °C (in the case of materials with additives) and to temperatures of 2970 °C (in the case of materials sintered with ZrB2 or HfB2), the hardness and fracture toughness decreased. Thus, the hardness of the material prepared from ZrB2 decreased by 19 % and its fracture toughness – by 18 %, and of that prepared from ZrB2–20 % SiC – by 46 % and 32 %, respectively. The hardness of the material prepared from HfB2 decreased by 46 %, its fracture toughness – by 55 %, and of that prepared from HfB2-30 % SiC, after heating decreased by 40 %, but its fracture toughness increased by 15 %. The sintered HfB2 (with a density of 10.4 g/cm3) before heating showed a hardness of HV(9.8 N)=21.27±0.84 GPa, HV(49 N)=19.29±1.34 and HV(98 N)=19.17±0.5, and fracture toughness K1C(9.8 N)=0.47 MH·m0.5, and ZrB2 with a density of 6.2 g/cm3 was characterized by HV(9.8 N)=17.66±0.60 GPa, HV(49 N)=15.25±1.22 GPa and HV(98 N)=15.32±0.36 GPa, K1C(9.8 N)=4.3 MH·m0.5. Material sintered with HfB2-30 % SiC (density 6.21 g/cm3) had Hv(9.8 N)=38.1±1.4 GPa, HV(49 N)=27.7±2.8 GPa, and K1C(9.8 N)=8.1 MH·m0.5, K1C(49 H)=6.8 MH·m0.5. The sintered with ZrB2-20 % SiC material had density of 5.04 g/cm3, HV(9.8 N)=24.2±1.9 GPa, HV(49 N)=16.7±2.8 GPa, K1C(49 H)=7.1 MH·m0.5. The SiC addition to the initial mixture significantly reduces the elasticity of the materials.

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