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

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.

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Influence of Hemp Shives Size on Hygro-Thermal and Mechanical Properties of a Hemp-Lime Composite

Materials ◽

10.3390/ma13235383 ◽

2020 ◽

Vol 13 (23) ◽

pp. 5383

Author(s):

Przemysław Brzyski ◽

Mateusz Gładecki ◽

Monika Rumińska ◽

Karol Pietrak ◽

Michał Kubiś ◽

...

Keyword(s):

Thermal Conductivity ◽

Specific Heat ◽

Preparation Method ◽

Total Porosity ◽

Vapor Permeability ◽

Thermal And Mechanical Properties ◽

Lifting Capacity ◽

The Individual ◽

Industrial Hemp ◽

Properties Of Composites

Different fractions of hemp shives are used in the mixtures of the hemp–lime composite. The market offers shives of different granulation. It depends on the type of industrial hemp and on the capabilities of decortication machines. The aim of the research presented in the article is to check differences in the mechanical and hygro-thermal properties of composites with different shives fractions. The research part of the paper presents the preparation method and investigation on hemp–lime composites. Apparent density, total porosity, thermal conductivity, capillary uptake, vapor permeability, specific heat, mass absorptivity, flexural and compressive strength were examined. The results confirm that the shives fraction influences the individual properties of the composites. Hemp–lime composites with fine shives are characterized by higher water absorption, thermal conductivity, mechanical strength, vapor permeability as well as lower capillary-lifting capacity and specific heat than composites with thick shives.

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

Nanoscale Advances ◽

10.1039/d1na00415h ◽

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)...

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

Journal of Materials Research ◽

10.1557/jmr.2004.0416 ◽

2004 ◽

Vol 19 (11) ◽

pp. 3270-3278 ◽

Cited By ~ 31

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.

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

Materials ◽

10.3390/ma12172770 ◽

2019 ◽

Vol 12 (17) ◽

pp. 2770 ◽

Cited By ~ 1

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.

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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

10.5194/egusphere-egu2020-886 ◽

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

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.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.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.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%.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.Keywords: &#160;&#160;plaster, enhancement, properties, mechanical, thermal, Morocco

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Thermal and Mechanical Properties of Epoxy Resin Functionalized Copper and Graphene Hybrids using In-situ Polymerization Method

Current Nanoscience ◽

10.2174/1573413716999200820145518 ◽

2020 ◽

Vol 16 ◽

Author(s):

Nadia A. Ali ◽

Alaa M. Abd-Elnaiem ◽

Seenaa I. Hussein ◽

Asmaa Sh. Khalil ◽

Hatem R. Alamri ◽

...

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Wear Resistance ◽

Epoxy Resin ◽

Hybrid Composite ◽

Hybrid Composites ◽

Weight Ratio ◽

Epoxy Composites ◽

Thermal And Mechanical Properties ◽

Maximum Hardness

Objective: In this work, graphene (Gr) or/and Cu particles are used to improve the thermal and mechanical properties of epoxy resin. Methods: Various contents of Gr powder (0.1, 0.3, and 0.5 wt%), Cu powder (10, 30, and 50 wt%) were loaded to epoxy to form Gr/epoxy and Cu/epoxy composites, respectively. In addition, hybrids epoxy/Cu/Gr samples were prepared with a selection of lowest (0.1 and 10) and highest (0.5 and 50) ratios of Gr, and Cu, respectively. Results: The thermal conductivity increases with the increasing weight ratio of Gr and Cu as compared to the pure epoxy. The Thermogravimetric analysis (TGA) of epoxy composites and hybrid composites reveals an improvement in the thermal stability. In addition, the mechanical properties such as hardness shore D and the wear resistance are enhanced for both the epoxy composites and hybrids composites. However, the Ep+0.5wt%Gr+50wt%Cu hybrid composite has the maximum hardness 84, thermal conductivity of 3.84 W/m.K, it shows the lowest wear resistance 2.7×10-6 mm3/Nm at loading 10 N. Conclusion: The hybrid composite containing 0.5wt%Gr and 50wt%Cu shows the maximum hardness and thermal conductivity, as well as the lowest wear resistance when compared to other composites. The physical properties of the hybrid composite can be controlled by the host blend, and hence the morphology, and interfacial characteristics.

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Thermal and Mechanical Properties of Hf Hydrides with Various Hydrogen Content

MRS Proceedings ◽

10.1557/proc-1215-v18-02 ◽

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.

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Evolution of thermal and mechanical properties of mine tailings and fly ash mixtures during curing period

Canadian Geotechnical Journal ◽

10.1139/cgj-2012-0232 ◽

2014 ◽

Vol 51 (5) ◽

pp. 570-582 ◽

Cited By ~ 12

Author(s):

Joon Kyu Lee ◽

Julie Q. Shang

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Fly Ash ◽

Mine Tailings ◽

Mechanical Characteristics ◽

Early Stage ◽

Expansive Soils ◽

Thermal And Mechanical Properties ◽

Curing Period ◽

Compaction Energy

Fly ash is often used as a binder for modifying the properties of geomaterials, such as organic and expansive soils, sludge from water treatment, dredged sediments, mine tailings, etc. Changes in thermal and mechanical properties of compacted mixtures of mine tailings and fly ash are studied over a curing period of 120 h. The study includes the measurement of thermal conductivity, temperature, unconfined compressive strength, and elastic modulus. Effects of the amount of fly ash added to mine tailings, molding water content, and compaction energy on these properties are investigated. Pore-size distribution and surface texture are analyzed to characterize the microstructures of fly ash treated–mine tailings. Relationships between the thermal conductivity and properties that capture packing and mechanical characteristics of mine tailings and fly ash mixtures are established. These observations provide enhanced understanding of thermal, mechanical, and structural properties of fly ash–treated mine tailings, which is associated with the hydration process at the early stage of the mixtures.

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Incorporating MXene into Boron Nitride/Poly(Vinyl Alcohol) Composite Films to Enhance Thermal and Mechanical Properties

Polymers ◽

10.3390/polym13030379 ◽

2021 ◽

Vol 13 (3) ◽

pp. 379

Author(s):

Seonmin Lee ◽

Jooheon Kim

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Boron Nitride ◽

Composite Film ◽

Vinyl Alcohol ◽

Composite Films ◽

Poly Vinyl Alcohol ◽

Thermal And Mechanical Properties ◽

Conduction Path ◽

Thermally Conductive

Aggregated boron nitride (ABN) is advantageous for increasing the packing and thermal conductivity of the matrix in composite materials, but can deteriorate the mechanical properties by breaking during processing. In addition, there are few studies on the use of Ti3C2 MXene as thermally conductive fillers. Herein, the development of a novel composite film is described. It incorporates MXene and ABN into poly(vinyl alcohol) (PVA) to achieve a high thermal conductivity. Polysilazane (PSZ)-coated ABN formed a heat conduction path in the composite film, and MXene supported it to further improve the thermal conductivity. The prepared polymer composite film is shown to provide through-plane and in-plane thermal conductivities of 1.51 and 4.28 W/mK at total filler contents of 44 wt.%. The composite film is also shown to exhibit a tensile strength of 11.96 MPa, which is much greater than that without MXene. Thus, it demonstrates that incorporating MXene as a thermally conductive filler can enhance the thermal and mechanical properties of composite films.

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Microstructures and Mechanical Properties of Al-2Fe-xCo Ternary Alloys with High Thermal Conductivity

Materials ◽

10.3390/ma13173728 ◽

2020 ◽

Vol 13 (17) ◽

pp. 3728

Author(s):

Gan Luo ◽

Yujian Huang ◽

Chengbo Li ◽

Zhenghua Huang ◽

Jun Du

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Tensile Strength ◽

Ultimate Tensile Strength ◽

Fine Particles ◽

Ternary Alloys ◽

Thermal And Mechanical Properties ◽

Free Electrons ◽

Unmodified Alloy ◽

Cast Alloys

The microstructures, mechanical properties, and thermal conductivity (TC) of Al-2Fe-xCo (x = 0~0.8) alloys in as-cast, homogeneous annealed, and cool rolled states are systematically studied. Results indicate that appropriate Co modification (x ≤ 0.5) simultaneously improves the thermal and mechanical properties of as-cast Al-2Fe alloys. The improvement of TC is attributed to ameliorating the morphology of primary Al3Fe phases from needles to short rods and fine particles, which decreases the scattering probability of free electrons during the electronic transmission. However, further increasing the Co content (x = 0.8) decreases the TC due to the formation of a coarse plate-like Al2FeCo phase. Besides, the thermal conductivity of annealed Al-2Fe-xCo alloys is higher than that of as-cast alloys because of the elimination of lattice defects and spheroidization of Al3Fe phases. After cool rolling with 80 % deformation, thermal conductivity of alloys slightly increases due to the breaking down of Al2FeCo phases. The rolled Al-2Fe-0.3Co alloy exhibits the highest thermal conductivity, which is about 225 W/(m·K), approximately 11 % higher than the as-cast Al-2Fe sample. The ultimate tensile strength (UTS) and elongation (EL) of as-cast Al-2Fe-0.5Co (UTS: 138 MPa; EL: 22.0 %) are increased by 35 % and 69 %, respectively, compared with those of unmodified alloy (UTS: 102 MPa; EL: 13.0 %).

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