scholarly journals Mineral Composition, Pore Structure, and Mechanical Characteristics of Pyroxene Granite Exposed to Heat Treatments

Minerals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 553 ◽  
Author(s):  
Shang ◽  
Zhang ◽  
Xu ◽  
Liu ◽  
Xing
Keyword(s):  
Thermal Expansion ◽  
Elastic Modulus ◽  
High Temperature ◽  
Pore Structure ◽  
Failure Mechanism ◽  
Mineral Composition ◽  
Mechanical Characteristics ◽  
P Wave ◽  
Rock Porosity ◽  
Granite Samples

In deep geoengineering, including geothermal development, deep mining, and nuclear waste geological disposal, high temperature significantly affects the mineral properties of rocks, thereby changing their porous and mechanical characteristics. This paper experimentally studied the changes in mineral composition, pore structure, and mechanical characteristics of pyroxene granite heated to high temperature (from 25 °C to 1200 °C). The results concluded that (1) the high-temperature effect can be roughly identified as three stages: 25–500 °C, 500–800 °C, 800–1200 °C. (2) Below 500 °C, the maximum diffracted intensities of the essential minerals are comparatively stable and the porous and mechanical characteristics of granite samples change slightly, mainly due to mineral dehydration and uncoordinated thermal expansion; additionally, the failure mechanism of granite is brittle. (3) In 500–800 °C, the diffraction angles of the minerals become wider, pyroxene and quartz undergo phase transitions, and the difference in thermal expansion among minerals reaches a peak; the rock porosity increases rapidly by 1.95 times, and the newly created pores caused by high heat treatment are mainly medium ones with radii between 1 μm and 10 μm; the P-wave velocity and the elastic modulus decrease by 62.5% and 34.6%, respectively, and the peak strain increases greatly by 105.7%, indicating the failure mode changes from brittle to quasi-brittle. (4) In 800–1200 °C, illite and quartz react chemically to produce mullite and the crystal state of the minerals deteriorate dramatically; the porous and mechanical parameters of granite samples all change significantly and the P-wave, the uniaxial compressive strength (UCS), and the elastic modulus decrease by 81.30%, 81.20%, and 92.52%, while the rock porosity and the shear-slip strain increase by 4.10 times and 11.37 times, respectively; the failure mechanism of granite samples transforms from quasi-brittle to plastic, which also was confirmed with scanning electron microscopy (SEM).

scholarly journals Experimental Research on the Mechanical Characteristics and the Failure Mechanism of Coal-Rock Composite under Uniaxial Load

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Ke Yang ◽  
Zhen Wei ◽  
Xiaolou Chi ◽  
Yonggang Zhang ◽  
Litong Dou ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Acoustic Emission ◽  
Elastic Modulus ◽  
Crack Propagation ◽  
Failure Mechanism ◽  
Poisson’S Ratio ◽  
Mechanical Characteristics ◽  
Poisson's Ratio ◽  
Energy Value ◽  
Coal Rock

Due to the influence of the component structure and combination modes, the mechanical characteristics and failure modes of the coal-rock composite show different characteristics from the monomer. In order to explore the effect of different coal-rock ratios on the deformation and the failure law of the combined sample, the RMT rock mechanics test system and acoustic emission real-time monitoring system are adopted to carry out uniaxial compression tests on coal, sandstone, and three kinds of combined samples. The evolution rules of the mechanical parameters of the combined samples, such as the uniaxial compressive strength, elastic modulus, and Poisson’s ratio, are obtained. The expansion and failure deformation characteristics of the combined sample are analyzed. Furthermore, the evolution laws of the fractal and acoustic emission signals are combined to reveal the crack propagation and failure mechanism of the combined samples. The results show that the compressive strength and elastic modulus of the combined sample increase with the decrease of the coal-rock ratios, and Poisson’s ratio decreases with the decrease of the coal-rock ratios. The strain softening weakens at the postpeak stage, which shows an apparent brittle failure. The combined sample of coal and sandstone has different degrees of damages under load. The coal is first damaged with a high degree of breakage, with obvious tensile failure. The acoustic emission energy value presents different stage characteristics with increasing load. Crackling sound occurs in the destroy section before the sample reaches the peak, along with small coal block ejection and the partial destruction. The energy value fluctuates violently, with the appearance of several peaks. At the postpeak stage, the coal samples expand rapidly with a loud crackling sound in the destroy section, and the energy value increases dramatically. The crack propagation induces the damage in the sandstone; when the energy reaches the limit value, the instantaneous release of elastic energy leads to the overall structural instability.

High Temperature Thermal Expansion and Elastic Modulus of Steels Used in Mill Rolls

2011 ◽  
Vol 21 (2) ◽  
pp. 271-279 ◽  
Author(s):  
Alexander Laptev ◽  
Bernd Baufeld ◽  
Akhilesh Kumar Swarnakar ◽  
Stanislav Zakharchuk ◽  
Omer van der Biest
Keyword(s):  
Thermal Expansion ◽  
Elastic Modulus ◽  
High Temperature

scholarly journals INFLUENCE OF ELEVATED TEMPERATURES ON MECHANICAL PROPERTIES OF CONCRETE

2018 ◽  
Vol 14 (1) ◽  
pp. 178-184 ◽  
Author(s):  
Vladimir I. Andreev ◽  
Lyudmila S. Polyakova
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Elastic Modulus ◽  
Shear Deformation ◽  
Mechanical Characteristics ◽  
Elevated Temperatures ◽  
Strength Functions ◽  
Deformation Coefficient

he paper considers the influence of elevated temperatures in the range from 20°C to 800°C in the mechanical properties of the concrete the thermal expansion, elastic modulus, shear deformation coefficient, strength. Functions describing the dependences of the mechanical characteristics of concrete on temperature as well as functions approximating the nonlinear diagram deformation of concrete at elevated temperatures are pro-posed.

Ceramic Nano Composites for Thermal Insulators

2014 ◽  
Vol 960-961 ◽  
pp. 126-129
Author(s):  
Hae Noo Ree Jung ◽  
Yoon Kwang Lee ◽  
Hyung Ho Park
Keyword(s):  
Heat Treatment ◽  
Mechanical Property ◽  
Elastic Modulus ◽  
High Temperature ◽  
Mechanical Strength ◽  
Thermal Property ◽  
Pore Structure ◽  
Nano Composites

In this research, nanopore composite had an effect on enhancing thermal property and mechanical property. The nanopore composite maintained the pore structure and enhanced mechanical property. Al2O3 xerogel was collapsed after heat treatment over 1000°C and they had weak mechanical strength because of pores. For maintenance of pore at high temperature and improvement of mechanical strength, Al2O3 whisker was hybridized. The Al2O3 whiskers in nanopore composite play the role of pillar during heat treatment. The mechanical property of Al2O3 xerogel was improved through complexation with Al2O3 whisker. The elastic modulus of nanopore composite increased 225 % from Al2O3 xerogel.

scholarly journals Effect of Gd2O3 Addition on the Microstructure and Properties of Gd2O3-Yb2O3-Y2O3-ZrO2 (GYYZO) Ceramics

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7470
Author(s):  
Pei-Hu Gao ◽  
Sheng-Cong Zeng ◽  
Can Jin ◽  
Bo Zhang ◽  
Bai-Yang Chen ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Fracture Toughness ◽  
Thermal Expansion ◽  
Elastic Modulus ◽  
High Temperature ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Thermal Barrier ◽  
High Temperature Stability ◽  
Coating Materials

Gd and Yb elements have high chemical stability, which can stabilize the solid solution in ZrO2. Gd2O3 and Yb2O3 have high melting points, and good oxidation resistance in extreme environments, stable chemical properties. Therefore, Gd2O3 and Yb2O3 were added to ZrO2 to stabilize oxides, improve the high temperature stability, and effectively decrease the thermal conductivity at high temperature. In this work, 5 wt% Yb2O3 and 5 wt%, 10 wt%, 15 wt% Gd2O3 were doped into 8 wt% Y2O3 stabilized ZrO2 (8YSZ) powders as thermal barrier coating materials, and sintered at 1650 °C for 6 h, 12 h, 24 h. The effects of Gd2O3 addition on the microstructure, density, thermal conductivity, hardness, and fracture toughness of Gd2O3-Yb2O3-Y2O3-ZrO2 (GYYZO) bulk composite ceramics were investigated. It was found that the densification of the 8YSZ bulk and GYYZO bulk with 15 wt% Gd2O3 reached 96.89% and 96.22% sintered at 1650 °C for 24 h. With the increase of Gd2O3 addition, the hardness, elastic modulus and fracture toughness of the GYYZO bulk increased and the thermal conductivity and thermal expansion coefficient of the GYYZO bulk decreased. GYYZO bulk with 15 wt% Gd2O3 sintered at 1650 °C for 24h had the highest hardness, elastic modulus and fracture toughness of 15.61 GPa, 306.88 GPa, 7.822 MPa·m0.5, and the lowest thermal conductivity and thermal expansion coefficient of 1.04 W/(m·k) and 7.89 × 10−6/°C at 1100 °C, respectively. The addition of Gd2O3 into YSZ could not only effectively reduce the thermal conductivity but also improve the mechanical properties, which would improve the thermal barrier coatings’ performances further.

Evaluating High Temperature Modulus and Strength of Alumina Tube in Vacuum by a Modified Split Ring Method

2016 ◽  
Vol 680 ◽  
pp. 9-12
Author(s):  
Zhao Liu ◽  
Yi Wang Bao ◽  
Chun Lin Hu ◽  
De Tian Wan ◽  
Yuan Tian
Keyword(s):  
Thermal Expansion ◽  
Elastic Modulus ◽  
High Temperature ◽  
Ambient Temperature ◽  
Room Temperature ◽  
Bending Strength ◽  
Heating Furnace ◽  
Alumina Tube ◽  
Split Ring ◽  
Ring Method

Alumina is a typical ceramic material and possesses high strengthand stiffness at both room temperature and high temperature. The split ring methodhad been established to evaluate the elastic modulus and bending strength of aluminatube materials at ambient temperature. However, both equations for modulus andstrength became lightly inapplicable with the increased temperature. For theelastic modulus, it was lack of precise approaches and advices for deformationmeasurement in the heating furnace. For the bending strength, changes of sampledimensions due to thermal expansion would take an effect on the calculatingresults. In this work, several improvements have been taken into account tocalibrate the above deviations. Results revealed that the modulus and strengthregularly decreased from room temperature to 1300 °C and accorded well with other conventional testing methods.It proved the accuracy and reliability of this modified split ring method,which might be used to evaluate other ceramic tube materials at hightemperature.

NILO ALLOY 36

Alloy Digest ◽  
1987 ◽  
Vol 36 (8) ◽  
Keyword(s):  
Thermal Expansion ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Constant Coefficient ◽  
Coefficient Of Thermal Expansion ◽  
Heat Treating ◽  
Temperature Performance ◽  
Iron Nickel

Abstract NILO alloy 36 is a binary iron-nickel alloy having a very low and essentially constant coefficient of thermal expansion at atmospheric temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Fe-79. Producer or source: Inco Alloys International Inc..

UNISPAN LR35

Alloy Digest ◽  
1971 ◽  
Vol 20 (1) ◽  
Keyword(s):  
Thermal Expansion ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Coefficient Of Thermal Expansion ◽  
Heat Treating ◽  
Temperature Performance ◽  
Operational Level

Abstract UNISPAN LR35 offers the lowest coefficient of thermal expansion of any alloy now available. It is a low residual modification of UNISPAN 36 for fully achieving the demanding operational level of precision equipment. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and surface treatment. Filing Code: Fe-46. Producer or source: Cyclops Corporation.

RED X-20

Alloy Digest ◽  
1960 ◽  
Vol 9 (2) ◽  
Keyword(s):  
Wear Resistance ◽  
Thermal Expansion ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Coefficient Of Thermal Expansion ◽  
Heat Treating ◽  
Aluminum Silicon Alloy ◽  
Temperature Performance

Abstract RED X-20 is a heat treatable hypereutectic aluminum-silicon alloy with excellent wear resistance and a very low coefficient of thermal expansion. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-89. Producer or source: Apex Smelting Company.

CARPENTER INVAR 36 ALLOY

Alloy Digest ◽  
2004 ◽  
Vol 53 (8) ◽  
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Carbon Steel ◽  
Physical Properties ◽  
Iron Alloy ◽  
Nickel Iron ◽  
Temperature Performance ◽  
Technology Corporation ◽  
Carpenter Technology Corporation ◽  
Nickel Iron Alloy

Abstract Carpenter Invar 36 alloy is a 36% nickel-iron alloy with a rate of thermal expansion approximately one-tenth that of carbon steel at temperatures up to 204 deg C (400 deg F). This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on low and high temperature performance. Filing Code: FE-131. Producer or source: Carpenter Technology Corporation.

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