Some Properties of Stratified Composites

2010 ◽  
Author(s):  
Adrian Circiumaru ◽  
Vasile Bria ◽  
Iulian-Gabriel Birsan ◽  
Gabriel Andrei ◽  
Dumitru Dima
Keyword(s):  
Mechanical Properties ◽  
Magnetic Particles ◽  
Bending Strength ◽  
Electric Circuit ◽  
Textile Composites ◽  
Hybrid Technique ◽  
Layer By Layer ◽  
Filled Polymer ◽  
Polymer Layers ◽  
The Right

The multi-component composites could represent the cheapest solution when controllable properties are required. In order to establish the right amount of filler it is necessary to analyze not only the electro-magnetic and mechanical properties but also, the thermal ones. The filler presence in the matrix produces discontinuities at the fibre-matrix interface with consequences regarding mechanical properties. Using a single filler it is possible to improve one or two properties electrical and thermal conductivity for instance and mean time to induce a decrease of other properties as bending strength, shock resistance etc. Using polymer layers with relatively high electrical conductivity as external layers of laminate and magnetic particles filled polymer as core layers. An electric circuit might be, at the same time, the reinforcement of a composite leading to lighter structures and, based on carbon fiber’s properties might transmit information about the material’s loading, temperature or integrity. Fabric reinforced or textile composites are used in aerospace, automotive, naval and other applications. They are convenient material forms providing adequate stiffness and strength in many structures. The microstructure of composite reinforced with woven, braided, or stitched networks is significantly different from that of tape based laminates. The properties of the composite depend not only on the properties of the components but on quality and nature of the interface between the components and its properties. Reinforced composites with filled epoxy matrix were formed using a hybrid technique consisting in layer-by-layer adding of reinforcement sheets into a glass mould. Various distributions of reinforcement sheets and filled polymer layers were realized in order to point out the ways in which the final properties might be controlled. Mechanical properties were analyzed.

Influence of nozzle temperature and volumetric filling on the mechanical properties of 3D-printed PEEK

2020 ◽  
Vol 62 (4) ◽  
pp. 351-356
Author(s):  
Danny Vogel ◽  
Volker Weißmann ◽  
Leo Rührmund ◽  
Harald Hansmann ◽  
Rainer Bader
Keyword(s):  
Mechanical Properties ◽  
Fused Deposition Modeling ◽  
Bending Strength ◽  
Layer By Layer ◽  
Bending Properties ◽  
Filling Degree ◽  
Fused Deposition ◽  
3D Printed ◽  
Injection Molded ◽  
Nozzle Temperature

Abstract Fused deposition modeling is a layer-by-layer 3D printing technology used to additively manufacture polymers. A major benefit of 3D-printed polymers is the option of tailoring their mechanical properties by varying the process parameters. In addition, the present study investigates the influence of the filling degree (50 % or 100 %) and the nozzle temperature during manufacturing on the mechanical properties of 3D-printed poly-ether-ether-ketone (PEEK) material. PEEK samples were built either compact (filling degree 100 %) or closed-cell porous (filling degree 50 %), using three different nozzle temperatures (390 °C, 430 °C and 470 °C). In static bending tests, the bending properties were evaluated and compared with injection molded PEEK samples. Bending strength and modulus increased up to 21.1 %, when the nozzle temperature was increased and up to 40.8 % when the volumetric filling was altered. The results indicate that nozzle temperature and volumetric filling can be altered to tailor the bending properties of 3D-printed PEEK for particular applications. However, the mechanical properties of the 3D-printed samples determined in the current study could not achieve those of the properties of the injection molded PEEK.

Preparation and Characteristics of Gradient Silk Fibroin/Hydroxyapatite Porous Composites

2009 ◽  
Vol 610-613 ◽  
pp. 1231-1236
Author(s):  
Wei Wei Xu ◽  
Jian Bing Liu ◽  
Ming Zhong Li ◽  
Shen Zhou Lu ◽  
Miao Liang Luo
Keyword(s):  
Mechanical Properties ◽  
Silk Fibroin ◽  
Bending Strength ◽  
Bone Tissue Regeneration ◽  
Gradient Material ◽  
Layer By Layer ◽  
Porous Composite ◽  
Pressing Method ◽  
Linear Gradient ◽  
Porous Composites

The gradient silk fibroin (SF)/ hydroxyapatite (HA) porous composite used for the scaffold of cartilage-bone tissue regeneration was prepared with SF powder and HA powder by layer-by-layer mould pressing method and granular NaCl as porogent. The characteristics were performed by Electron Microprobe and Energy Dispersive Spectometer (EDS). It indicated that the distribution of SF and HA presented linear gradient along the thickness direction in the materials. The porosity of composites increased with NaCl content increasing, while the density decreased. As the result of mechanical properties measurement, the bending strength and compressive strength decreased with NaCl content increasing. Compared the mechanical properties between gradient material and non-gradient material, it indicated that bending strength of gradient SF/HA porous material was higher than non-gradient SF/HA porous material’s.

Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Grain Boundary ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Structure And Properties ◽  
Steam Turbines ◽  
Friction Forces ◽  
Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

Control of humping phenomenon and analyzing mechanical properties of Al–Si wire-arc additive manufacturing fabricated samples using cold metal transfer process

2021 ◽  
pp. 095440622199840
Author(s):  
Yashwant Koli ◽  
N Yuvaraj ◽  
Aravindan Sivanandam ◽  
Vipin
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Heat Input ◽  
Large Scale ◽  
High Deposition Rate ◽  
Bead Geometry ◽  
Layer By Layer ◽  
Cold Metal Transfer ◽  
Geometrical Shapes ◽  
Wire Arc Additive Manufacturing

Nowadays, rapid prototyping is an emerging trend that is followed by industries and auto sector on a large scale which produces intricate geometrical shapes for industrial applications. The wire arc additive manufacturing (WAAM) technique produces large scale industrial products which having intricate geometrical shapes, which is fabricated by layer by layer metal deposition. In this paper, the CMT technique is used to fabricate single-walled WAAM samples. CMT has a high deposition rate, lower thermal heat input and high cladding efficiency characteristics. Humping is a common defect encountered in the WAAM method which not only deteriorates the bead geometry/weld aesthetics but also limits the positional capability in the process. Humping defect also plays a vital role in the reduction of hardness and tensile strength of the fabricated WAAM sample. The humping defect can be controlled by using low heat input parameters which ultimately improves the mechanical properties of WAAM samples. Two types of path planning directions namely uni-directional and bi-directional are adopted in this paper. Results show that the optimum WAAM sample can be achieved by adopting a bi-directional strategy and operating with lower heat input process parameters. This avoids both material wastage and humping defect of the fabricated samples.

scholarly journals 3D Printing of High Viscosity Reinforced Silicone Elastomers

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2239
Author(s):  
Nicholas Rodriguez ◽  
Samantha Ruelas ◽  
Jean-Baptiste Forien ◽  
Nikola Dudukovic ◽  
Josh DeOtte ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
New Technologies ◽  
Three Dimensional ◽  
High Viscosity ◽  
Layer By Layer ◽  
Silicone Elastomers ◽  
Uv Curable ◽  
Octet Truss ◽  
Tunable Mechanical Properties

Recent advances in additive manufacturing, specifically direct ink writing (DIW) and ink-jetting, have enabled the production of elastomeric silicone parts with deterministic control over the structure, shape, and mechanical properties. These new technologies offer rapid prototyping advantages and find applications in various fields, including biomedical devices, prosthetics, metamaterials, and soft robotics. Stereolithography (SLA) is a complementary approach with the ability to print with finer features and potentially higher throughput. However, all high-performance silicone elastomers are composites of polysiloxane networks reinforced with particulate filler, and consequently, silicone resins tend to have high viscosities (gel- or paste-like), which complicates or completely inhibits the layer-by-layer recoating process central to most SLA technologies. Herein, the design and build of a digital light projection SLA printer suitable for handling high-viscosity resins is demonstrated. Further, a series of UV-curable silicone resins with thiol-ene crosslinking and reinforced by a combination of fumed silica and MQ resins are also described. The resulting silicone elastomers are shown to have tunable mechanical properties, with 100–350% elongation and ultimate tensile strength from 1 to 2.5 MPa. Three-dimensional printed features of 0.4 mm were achieved, and complexity is demonstrated by octet-truss lattices that display negative stiffness.

How the work of adhesion affects the mechanical properties of silica-filled polymer composites

1994 ◽  
Vol 29 (9) ◽  
pp. 2406-2416 ◽  
Author(s):  
S. W. Shang ◽  
J. W. Williams ◽  
K. -J. M. Söderholm
Keyword(s):  
Mechanical Properties ◽  
Polymer Composites ◽  
Work Of Adhesion ◽  
Filled Polymer

scholarly journals Eco-Friendly, High-Density Fiberboards Bonded with Urea-Formaldehyde and Ammonium Lignosulfonate

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 220
Author(s):  
Petar Antov ◽  
Viktor Savov ◽  
Ľuboš Krišťák ◽  
Roman Réh ◽  
George I. Mantanis
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Urea Formaldehyde ◽  
Physical And Mechanical Properties ◽  
High Density ◽  
Thickness Swelling ◽  
Formaldehyde Content ◽  
Uf Resin ◽  
Natural Wood ◽  
European Standards

The potential of producing eco-friendly, formaldehyde-free, high-density fiberboard (HDF) panels from hardwood fibers bonded with urea-formaldehyde (UF) resin and a novel ammonium lignosulfonate (ALS) is investigated in this paper. HDF panels were fabricated in the laboratory by applying a very low UF gluing factor (3%) and ALS content varying from 6% to 10% (based on the dry fibers). The physical and mechanical properties of the fiberboards, such as water absorption (WA), thickness swelling (TS), modulus of elasticity (MOE), bending strength (MOR), internal bond strength (IB), as well as formaldehyde content, were determined in accordance with the corresponding European standards. Overall, the HDF panels exhibited very satisfactory physical and mechanical properties, fully complying with the standard requirements of HDF for use in load-bearing applications in humid conditions. Markedly, the formaldehyde content of the laboratory fabricated panels was extremely low, ranging between 0.7–1.0 mg/100 g, which is, in fact, equivalent to the formaldehyde release of natural wood.

scholarly journals Effect of Sintering Temperature on Microstructure and Mechanical Properties of Hot-Pressed Fe/FeAl2O4 Composite

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 422
Author(s):  
Kuai Zhang ◽  
Yungang Li ◽  
Hongyan Yan ◽  
Chuang Wang ◽  
Hui Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Hot Press ◽  
Microstructure And Mechanical Properties ◽  
Powder Particles ◽  
Hot Press Sintering ◽  
Sintering Method

An Fe/FeAl2O4 composite was prepared with Fe-Fe2O3-Al2O3 powder by a hot press sintering method. The mass ratio was 6:1:2, sintering pressure was 30 MPa, and holding time was 120 min. The raw materials for the powder particles were respectively 1 µm (Fe), 0.5 µm (Fe2O3), and 1 µm (Al2O3) in diameter. The effect of sintering temperature on the microstructure and mechanical properties of Fe/FeAl2O4 composite was studied. The results showed that Fe/FeAl2O4 composite was formed by in situ reaction at 1300 °C–1500 °C. With the increased sintering temperature, the microstructure and mechanical properties of the Fe/FeAl2O4 composite showed a change law that initially became better and then became worse. The best microstructure and optimal mechanical properties were obtained at 1400 °C. At this temperature, the grain size of Fe and FeAl2O4 phases in Fe/FeAl2O4 composite was uniform, the relative density was 96.7%, and the Vickers hardness and bending strength were 1.88 GPa and 280.0 MPa, respectively. The wettability between Fe and FeAl2O4 was enhanced with increased sintering temperature. And then the densification process was accelerated. Finally, the microstructure and mechanical properties of the Fe/FeAl2O4 composite were improved.

Sintered High Carbon Steels: Effect of Thermomechanical Treatments on their Mechanical and Wear Performance

2008 ◽  
Vol 591-593 ◽  
pp. 271-276 ◽  
Author(s):  
M.A. Martinez ◽  
R. Calabrés ◽  
J. Abenojar ◽  
Francisco Velasco
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Powder Metallurgy ◽  
Thermomechanical Treatment ◽  
Bending Strength ◽  
Carbon Steels ◽  
Tool Steels ◽  
High Carbon ◽  
Wear Performance ◽  
Metallographic Study

In this work, ultrahigh carbon steels (UHCS) obtained by powder metallurgy with CIP and argon sintered at 1150°C. Then, they were rolled at 850 °C with a reduction of 40 %. Finally, steels were quenched at 850 and 1000 °C in oil. In each step, hardness, bending strength and wear performance were evaluated. Obtained results are justified with a metallographic study by SEM. Both mechanical properties and wear resistance are highly favoured with the thermomechanical treatment that removes the porosity of the material. Moreover, final quenching highly hardens the material. The obtained material could be used as matrix for tool steels.

In Situ Preparation and Mechanical Properties of (ZrB2+ZrC)/Zr3[Al(Si)]4C6 Composites

2014 ◽  
Vol 602-603 ◽  
pp. 438-442
Author(s):  
Lei Yu ◽  
Jian Yang ◽  
Tai Qiu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
Raw Materials ◽  
Linear Increase ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Uniform Microstructure

Fully dense (ZrB2+ZrC)/Zr3[Al (Si)]4C6 composites with ZrB2 content varying from 0 to 15 vol.% and fixed ZrC content of 10 vol.% were successfully prepared by in situ hot-pressing in Ar atmosphere using ZrH2, Al, Si, C and B4C as raw materials. With the increase of ZrB2 content, both the bending strength and fracture toughness of the composites increase and then decrease. The synergistic action of ZrB2 and ZrC as reinforcements shows significant strengthening and toughing effect to the Zr3[Al (Si)]4C6 matrix. The composite with 10 vol.% ZrB2 shows the optimal mechanical properties: 516 MPa for bending strength and 6.52 MPa·m1/2 for fracture toughness. With the increase of ZrB2 content, the Vickers hardness of the composites shows a near-linear increase from 15.3 GPa to 16.7 GPa. The strengthening and toughening effect can be ascribed to the unique mechanical properties of ZrB2 and ZrC reinforcements, the differences in coefficient of thermal expansion and modulus between them and Zr3[Al (Si)]4C6 matrix, fine grain strengthening and uniform microstructure derived by the in situ synthesis reaction.

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