Thermal and Mechanical Properties of Hf Hydrides with Various Hydrogen Content

2009 ◽  
Vol 1215 ◽  
Author(s):  
Ken Kurosaki ◽  
Masato Ito ◽  
Yuki Kitano ◽  
Hiroaki Muta ◽  
Masayoshi Uno ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Vickers Hardness ◽  
Temperature Effects ◽  
Room Temperature ◽  
Atomic Ratio ◽  
Thermal And Mechanical Properties ◽  
Shear Moduli ◽  
Delta Phase

AbstractFine bulk samples of delta-phase Hf hydride with various hydrogen contents (CH) ranging from 1.62 to 1.72 in the atomic ratio (H/Hf) were prepared, and their thermal and mechanical properties were characterized. In the temperature range from room temperature to around 650 K, the heat capacity and thermal diffusivity of the samples were measured and the thermal conductivity was evacuated. The elastic modulus was calculated from the measured sound velocity. The Vickers hardness was measured at room temperature. Effects of CH and/or temperature on the properties of Hf hydrides were discussed. At room temperature, the thermal conductivity values of the Hf hydrides were 23 Wm−1K−1. The Young's and shear moduli and the Vickers hardness of Hf hydride decreased with increasing CH.

Thermal and Mechanical Properties of Aluminate Cementitious Functional Materials Enriched with Nano-SiO2 for Thermal Energy Storage

2014 ◽  
Vol 887-888 ◽  
pp. 77-80 ◽  
Author(s):  
Yu Shi ◽  
Hui Wen Yuan ◽  
Zhong Zi Xu ◽  
Chun Hua Lu ◽  
Ya Ru Ni ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Heat Treatment ◽  
Heat Capacity ◽  
Compressive Strength ◽  
Energy Storage ◽  
Thermal Energy ◽  
Functional Materials ◽  
Thermal And Mechanical Properties ◽  
Thermal Changes

This paper focuses on both thermal and mechanical properties of the composite pastes. Heat-treatment was carried out at temperatures up to 105 and 900 °C for 6h, respectively. Thermal conductivity of the specimens enriched with 3 wt% nanoSiO2 was approximately 60% higher than that of pure paste. Volume heat capacity of the composite pastes displayed 28% increase. Moreover, the composite pastes contributed to ~25% improvement of compressive strength. XRD, and TG-DSC were employed to investigate the cause of physical and thermal changes in the heated specimens.

scholarly journals Flame-retardant MXene/Polyimide Film with Outstanding Thermal and Mechanical Properties Based on the Secondary Orientation Strategy

2021 ◽  
Author(s):  
Yue Zhu ◽  
Qingyu Peng ◽  
Haowen Zheng ◽  
Fuhua Xue ◽  
Pengyang Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Transition Metal ◽  
Mechanical Performance ◽  
Polyimide Film ◽  
Polymeric Films ◽  
Two Dimensional ◽  
Thermal And Mechanical Properties ◽  
Metal Carbides ◽  
Transition Metal Carbides

With the development of multifunction and miniaturization in modern electronics, polymeric films with strong mechanical performance and high thermal conductivity are urgently needed. Two-dimensional transition metal carbides and nitrides (MXenes)...

Influence of additive composition on thermal and mechanical properties of β–Si3N4 ceramics

2004 ◽  
Vol 19 (11) ◽  
pp. 3270-3278 ◽  
Author(s):  
Xinwen Zhu ◽  
Hiroyuki Hayashi ◽  
You Zhou ◽  
Kiyoshi Hirao
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Fracture Toughness ◽  
Nitrogen Pressure ◽  
High Fracture Toughness ◽  
Oxygen Impurity ◽  
Thermal And Mechanical Properties ◽  
High Fracture ◽  
Doped Materials ◽  
Gas Pressure Sintering

Dense β–Si3N4 ceramics were fabricated from α–Si3N4 raw powder by gas-pressure sintering at 1900 °C for 12 h under a nitrogen pressure of 1 MPa, using four different kinds of additive compositions: Yb2O3–MgO, Yb2O3–MgSiN2, Y2O3–MgO, and Y2O3–MgSiN2. The effects of additive composition on the microstructure and thermal and mechanical properties of β–Si3N4 ceramics were investigated. It was found that the replacement of Yb2O3 by Y2O3 has no significant effect on the thermal conductivity and fracture toughness, but the replacement of MgO by MgSiN2 leads to an increase in thermal conductivity from 97 to 113 Wm-1K-1and fracture toughness from 8 to 10 MPa m1/2, respectively. The enhanced thermal conductivity of the MgSiN2-doped materials is attributed to the purification of β–Si3N4 grain and increase of Si3N4–Si3N4 contiguity, resulting from the enhanced growth of large elongated grains. The improved fracture toughness of the MgSiN2-doped materials is attributed to the increase of grain size and fraction of large elongated grains. However, the same thermal conductivity between the Yb2O3- and Y2O3-doped materials is related to not only their similar microstructures, but also the similar abilities of removing oxygen impurity in Si3N4 lattice between Yb2O3 and Y2O3. The same fracture toughness between the Yb2O3- and Y2O3-doped materials is consistent with their similar microstructures. This work implies that MgSiN2 is an effective sintering aid for developing not only high thermal conductivity (>110 Wm−1K−1) but also high fracture toughness (>10 MPa m1/2) of Si3N4 ceramics.

scholarly journals Influence of the Direction of Mixture Compaction on the Selected Properties of a Hemp-Lime Composite

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4629
Author(s):  
Przemysław Brzyski ◽  
Piotr Gleń ◽  
Mateusz Gładecki ◽  
Monika Rumińska ◽  
Zbigniew Suchorab ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Temperature Distribution ◽  
Preparation Method ◽  
Thermal And Mechanical Properties ◽  
Compaction Process ◽  
External Wall ◽  
Capillary Uptake ◽  
Parallel Direction ◽  
The Individual

The aim of the research presented in the article was to check the differences in the hygro-thermal and mechanical properties of hemp-lime composites with different shives fractions, depending on the direction of mixture compaction. The research part of the paper presents the preparation method and investigation on the composites. Thermal conductivity, capillary uptake, as well as flexural and compressive strengths were examined. Additionally, an analysis of the temperature distribution in the external wall insulated with the tested composites was performed. The results confirm that the direction of compaction influences the individual properties of the composites in a similar way, depending on the size of the shives. The differences are more pronounced in the case of the composite containing longer fractions of shives. Both thermal conductivity of the material and the capillary uptake ability are lower in the parallel direction of the compaction process. Composites exhibit greater stiffness, but they fail faster with increasing loads when loaded in the direction perpendicular to compaction.

scholarly journals Utilization of SiC and Cu Particles to Enhance Thermal and Mechanical Properties of Al Matrix Composites

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2770 ◽  
Author(s):  
Dongxu Wu ◽  
Congliang Huang ◽  
Yukai Wang ◽  
Yi An ◽  
Chuwen Guo
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
High Thermal Conductivity ◽  
Low Density ◽  
Matrix Composites ◽  
Thermal And Mechanical Properties ◽  
Cu Content ◽  
Sic Particles ◽  
Al Matrix Composites ◽  
Al Matrix

In this work, SiC and Cu particles were utilized to enhance the thermal and mechanical properties of Al matrix composites. The ball-milling and cold-compact methods were applied to prepare Al matrix composites, and the uniform distribution of SiC and Cu particles in the composite confirms the validity of our preparation method. After characterizing the thermal conductivity and the compressibility of the prepared composites, results show that small particles have a higher potential to improve compressibility than large particles, which is attributed to the size effect of elastic modulus. The addition of SiC to the Al matrix will improve the compressibility behavior of Al matrix composites, and the compressibility can be enhanced by 100% when SiC content is increased from 0 to 30%. However, the addition of SiC particles has a negative effect on thermal conductivity because of the low thermal conductivity of SiC particles. The addition of Cu particles to Al-SiC MMCs could further slightly improve the compressibility behavior of Al-SiC/Cu MMCs, while the thermal conductivity could be enhanced by about 100% when the Cu content was increased from 0 to 30%. To meet the need for low density and high thermal conductivity in applications, it is more desirable to enhance the specific thermal conductivity by enlarging the preparation pressure and/or sintering temperature. This work is expected to supply some information for preparing Al matrix composites with low density but high thermal conductivity and high compressibility.

Thermo-Physical Behaviour and Mechanical Properties of Experimentally Enhanced Rubberised Concrete Block

2014 ◽  
Vol 925 ◽  
pp. 169-174
Author(s):  
Khalid B. Najim ◽  
Ibrahim A. Al-Jumaily
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Concrete Block ◽  
Crumb Rubber ◽  
Concrete Wall ◽  
Normal Concrete ◽  
Physical Behaviour ◽  
Concrete Blocks ◽  
Rubber Concrete

The aim of the presented study is to investigate the thermo-physical behaviour and mechanical properties of mortar pre-coated crumb rubber concrete block. For this purpose, thermal conductivity, emissivity and effusively will be tested in addition to the specific heat capacity. Thereafter, dynamic calculator software will be used to study the behaviour of a wall that constructed using the suggested concrete block and a comparison with a normal concrete wall will be made. Compressive, splitting tensile and flexural strength were tested as well. The results show that concrete blocks which meet the requirement of strength can be produced with about 300 kg/m3 of crumb rubber aggregate.

Identification and enhancement of the thermal and mechanical properties of two types of plasters successively derived from gypsum: from the Safi basin and the High Atlas of Marrakech, Morocco

2020 ◽  
Author(s):  
imane baba ◽  
Mounsif Ibnoussina ◽  
Omar Witam
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Mechanical Strength ◽  
Setting Time ◽  
Density Measurement ◽  
Raw Material ◽  
Mechanical And Thermal Properties ◽  
Thermal And Mechanical Properties ◽  
X Ray Diffraction ◽  
High Atlas

<p>Over the past few decades, the construction industry has focused on sustainable, environmentally friendly and easily recyclable materials. The objective of this work is to characterize and enhance the thermal conductivity, mechanical strength and setting time of a composite material based on plaster and lime. This material is designed for use in plasters.</p><p>Two types of gypsum are studied, the first one belongs to the Safi basin, the second one characterizes the High Atlas of Marrakech and precisely Douar Tafza. Geologically speaking, the two sites have many similarities. They are characterized by a Meso-Cenozoic age coverage covering a deformed Paleozoic age basement.</p><p>The characterization of the plaster's raw material, gypsum, was necessary to determine its physical and geotechnical properties, mineralogy, thermal behaviour and microscopic structure. Several analyses have been developed such as: pycnometer density measurement, X-ray diffraction, infrared spectroscopy and scanning electron microscopy.</p><p>We made samples, of standardized dimensions, of two mixtures based on the two types of plaster reinforced by the addition of two types of lime from different localities. The latter are from Marrakech and the Agadir region. The water/plaster mass ratio was set at 0.75 and the addition of lime was achieved by increasing its percentage in slices by 12.5% and up to 50%.</p><p>The reinforcement of plaster with lime has enhanced its thermal and mechanical properties and setting time. The measurements show that the addition of lime has reduced the thermal conductivity and increased the mechanical strength of both types of plaster. In addition, following the addition of lime, the setting time has decreased and the basicity of the material has increased. Noting that the intrinsic properties of the raw material influence the mechanical and thermal properties of the material.</p><p><strong>Keywords:</strong>   plaster, enhancement, properties, mechanical, thermal, Morocco</p>

Microstructure and Mechanical Properties of Vacuum Sintered Austenitic Stainless Steel Parts

2010 ◽  
Vol 160-162 ◽  
pp. 915-920
Author(s):  
Shao Jiang Lin ◽  
Da Peng Feng ◽  
Qi Nian Shi
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Vickers Hardness ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Testing Machine ◽  
Microstructural Characterization ◽  
Tensile Testing Machine ◽  
Hardness Tester

This work presents the possibility of obtaining high density austenitic stainless steel parts by powder metallurgy (PM) and sintered in vacuum. Mechanical properties such as tensile strength, yield stress, elongation rate and Vickers hardness were measured by using a tensile testing machine and a Vickers hardness tester at room temperature. Microstructural characterization was performed by means of optical microscopy and scanning electron microscopy (SEM). The effect of sintering temperature on densification and mechanical properties of PM austenitic stainless steel has been investigated. The results show that density and mechanical properties were increased with the increase of sintering temperature, but when the sintering temperature is above 1340 °C, they increased slowly. The highest mechanical properties were obtained when sintering temperature was 1340 °C.

Nafion – Azole Composite Membranes for High Temperature PEMFC

2014 ◽  
Vol 783-786 ◽  
pp. 1692-1697
Author(s):  
Je Deok Kim ◽  
Mun Suk Jun
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
High Temperature ◽  
Proton Conductivity ◽  
Composite Membrane ◽  
Room Temperature ◽  
Composite Membranes ◽  
Thermal And Mechanical Properties ◽  
High Proton Conductivity ◽  
High Proton

Nafion-azole (benzimidazole, 1,2,4-triazole, 1,2,3-triazole) composite membranes were prepared by room temperature and autoclave solution processing for high temperature (above 100 °C) PEMFC. Among the various Nafion – azole composite membranes, Nafion – 1,2,3-triazole membrane showed excellent flexibility, thermal stability, and homogeneous structure. Nafion – 1,2,4-triazole composite membrane had high thermal and mechanical properties, and also showed high proton conductivity of 0.02 S/cm at the temperature of 160 °C under dry (N2) condition.

scholarly journals Effect of La and Sc Co-Addition on the Mechanical Properties and Thermal Conductivity of As-Cast Al-4.8% Cu Alloys

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1866
Author(s):  
Zhao-Xi Song ◽  
Yuan-Dong Li ◽  
Wen-Jing Liu ◽  
Hao-Kun Yang ◽  
Yang-Jing Cao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Grain Morphology ◽  
Cu Alloy ◽  
Average Grain Size ◽  
Sc Addition ◽  
Co Addition

The effects of La and La+Sc addition on mechanical properties and thermal conductivity of Al-4.8Cu alloy were comprehensively studied. The as-cast samples were characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and first-principles methods. The results reveal that the grain morphology of Al-4.8Cu alloy changes from dendrite to fine equiaxed grain with La, La+Sc addition. The average grain size of Al-Cu-La (Al-4.8Cu-0.4La) and Al-Cu-La-Sc (Al-4.8Cu-0.4La-0.4Sc) decreased by 37.2% (70.36 μm) and 63.3% (119.64 μm) respectively compared with Al-Cu (Al-4.8Cu). Al-Cu-La has the highest elongation among the three which is 34.4% (2.65%) higher than Al-Cu. Al-Cu-La-Sc has the highest ultimate tensile strength and yield strength which are 55.1% (80.9 MPa) and 65.2% (62.1 MPa) higher than Al-Cu, respectively. The thermal conductivity of Al-Cu-La and Al-Cu-La-Sc is 10.0% (18.797 W·m−1·k−1) and 6.5% (12.178 W·m−1·k−1) higher than Al-Cu alloy respectively. Compared with Al-Cu, Al-Cu-La has less shrinkage and porosity, the presence of Al4La and AlCu3 contribute a lot to the decrease of specific heat capacity and the increase of plasticity and toughness. The porosity of Al-Cu-La-Sc does not significantly decrease compared with Al-Cu-La, the presence of Al3Sc and AlCuSc bring about the increase of specific heat capacity and brittleness.

Sign in / Sign up

Export Citation Format

Share Document