scholarly journals Fabrication of Highly Filled Composites with an Innovative Miniaturized Spouted Bed

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 521
Author(s):  
Hannah Sophia Rothberg ◽  
Swantje Pietsch ◽  
Gerold A. Schneider ◽  
Stefan Heinrich

In nature bio-composites such as nacre show remarkable mechanical properties due to their complex hierarchical structure and high-volume fraction of its hard component. These composites are highly interesting for structural applications in different branches of industries for mechanical engineering and process technology. The aim of this work was to provide a scalable method for the production of highly filled composites by mimicking the structure of bio-composites. Therefore, composites from iron oxide (Fe2O3) and SBC-polymer (styrene-butadiene block copolymer) were fabricated by using a miniaturized spouted bed with an innovative fluidization gap design. Small iron oxide particles (25–45 μm) were fluidized in the spouted bed and coated with a polymer solution via a bottom spray nozzle. Afterwards the coated granules were hot-pressed and the mechanical properties of the obtained composites were tested. By this method composites with a bending strength of up to 6 MPa were fabricated. Although the mechanical properties of these artificial composites are still lower than those of the natural role models, it was shown that the spouted bed is a suitable technique for the fabrication of highly filled composites. For further optimization of the mechanical properties more complex and tailor-made starting materials will be used in following studies.

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1926 ◽  
Author(s):  
Lei Zhang ◽  
Zhifu Huang ◽  
Yangzhen Liu ◽  
Yupeng Shen ◽  
Kemin Li ◽  
...  

Mo2NiB2-Ni cermets have been extensively investigated due to their outstanding properties. However, studies have not systematically examined the effect of the powder milling process on the cermets. In this study, Mo, Ni, and B raw powders were subjected to mechanical ball milling from 1 h to 15 h. XRD patterns of the milled powders confirmed that a new phase was not observed at milling times of 1 h to 15 h. With the increase in the mechanical ball milling time from 1 h to 11 h, raw powders were crushed to small fragments, in addition to a more uniform distribution, and with the increase in the mechanical ball milling time to greater than 11 h, milled powders changed slightly. Mo2NiB2-Ni cermets were fabricated by reaction boronizing sintering using the milled powders at different ball milling times. The milling time significantly affected the microstructure and mechanical properties of Mo2NiB2-Ni cermets. Moreover, the Mo2NiB2 cermet powder subjected to a milling time of 11 h exhibited the finest crystal size and the maximum volume fraction of the Mo2NiB2 hard phase. Furthermore, the cermets with a milling time of 11 h exhibited a maximum hardness and bending strength of 87.6 HRA and 1367.3 MPa, respectively.


2020 ◽  
Vol 4 (1) ◽  
pp. 5
Author(s):  
Nhan Thi Thanh Nguyen ◽  
Obunai Kiyotaka ◽  
Okubo Kazuya ◽  
Fujii Toru ◽  
Shibata Ou ◽  
...  

In this research, three kinds of carbon fiber (CF) with lengths of 1, 3, and 25 mm were prepared for processing composite. The effect of submicron glass fiber addition (sGF) on mechanical properties of composites with different CF lengths was investigated and compared throughout static tests (i.e., bending, tensile, and impact), as well as the tension-tension fatigue test. The strengths of composites increased with the increase of CF length. However, there was a significant improvement when the fiber length changed from 1 to 3 mm. The mechanical performance of 3 and 25 mm was almost the same when having an equal volume fraction, except for the impact resistance. Comparing the static strengths when varying the sGF content, an improvement of bending strength was confirmed when sGF was added into 1 mm composite due to toughened matrix. However, when longer fiber was used and fiber concentration was high, mechanical properties of composite were almost dependent on the CF. Therefore, the modification effect of matrix due to sGF addition disappeared. In contrast to the static strengths, the fatigue durability of composites increased proportionally to the content of glass fiber in the matrix, regardless to CF length.


2021 ◽  
Vol 6 (1) ◽  
pp. 30-37
Author(s):  
Sri Hastuti ◽  
Herru Santosa Budiono ◽  
Diki Ilham Ivadiyanto ◽  
Muhammad Nurdin Nahar

Inovasi baru serat dari sabut kelapa dimanfaatkan untuk meningkatkan nilai ekonomis dari serat sabut kelapa, oleh karena itu dirancanglah pendayagunaan serat dari sabut kelapa untuk penguat komposit dengan material serat alam yang biodegradable. Hal ini untuk mendukung penggunaan komposit yang ramah terhadap lingkungan dan mengurangi penggunaan material komposit serat sintetis yang polutan. Tujuan penelitian adalah menganalisis sifat mekanik pada komposit serat alam bermaterial serat dari sabut kelapa yang ramah lingkungan. Metode penelitian pembuatan komposit berpenguat serat dari sabut kelapa dilakukan treatment NaOH 15% selama 5 jam dan fraksi volume serat 10 %, 15 %, dan 20 %. Komposit  serat dari sabut kelapa dengan matriks UPRs 157 BQTN dengan hardener MEXPO. Pengujian mekanik dilakukan uji bending menggunakan standar ASTM D790 dan uji impak  menggunakan standar ASTM D5941.  Pengujian impak komposit serat alam menunjukkan ketangguhan impak komposit pada fraksi volume serat 20% dengan nilai 0.017588J/mm2. Hasil pengujian menunjukkan peningkatan fraksi volume serta berpengaruh terhadap peningkatan kekuatan bending komposit serat dari sabut kelapa  dengan kekuatan optimum bending pada fraksi volume serat 10% dengan nilai 44,33N/mm2. Hal ini menunjukkan peningkatan fraksi volume serat dengan perendaman NaOH 15% akan meningkatkan sifat mekanik bending dan impak komposit. Perendaman NaOH memberikan pengaruh daya serap sabut kelapa terhadap matrik Unsaturated Polyester yang dapat meningkatkan daya rekat antara penguat serat dengan matrik sehingga meningkatkan sifat mekanik bending dan impak komposit. ABSTRACT The innovation of coco fiber is used to increase the economic value of coconut coir, therefore the utilization of coconut fiber for reinforcing composites with biodegradable natural fiber material is designed. This is to support the use of composites that are friendly to the environment and reduce the use of pollutant synthetic fiber composite materials. The research objective was to analyze the mechanical properties of natural fiber composites with environmentally friendly coconut fiber as material. The research method of making fiber-reinforced composites from coconut coir was carried out by 15% NaOH treatment for 5 hours and a fiber volume fraction of 10%, 15%, and 20%. Composite fiber from coconut coir with UPRs 157 BQTN matrix with MEXPO hardener. Mechanical testing is carried out using the ASTM D790 standard and the impact test using the ASTM D5941 standard. The impact test of natural fiber composites showed the impact toughness of the composite at a fiber volume fraction of 20% with a value of 0.017588 J/ mm2. The test results showed an increase in volume fraction and an effect on the increase in the bending strength of coconut fiber composites with the optimum bending strength at a fiber volume fraction of 10% with a value of 44.33N /mm2. This shows that the increase in fiber volume fraction by immersion in 15% NaOH will increase the bending mechanical properties and the impact of the composite. Soaking NaOH has an effect on the absorption power of coconut coir on the Unsaturated Polyester matrix which can increase the adhesion between the fiber reinforcement and the matrix thereby increasing the bending mechanical properties and impact of the composite.


2015 ◽  
Vol 813-814 ◽  
pp. 116-120
Author(s):  
K.S. Arun ◽  
T. Panneerselvam ◽  
S. Raghuraman

Now a day’s Hybrid Metal Matrix composites has a large number of applications in automobiles, aircrafts and structural applications like brake rotors, engine parts and cylinder liners. The aim of this study is to determine the mechanical properties of boron carbide (B4C) and zirconium silicate (ZrSiO4) particulate reinforced with AA6063 alloy composites. In this experimental study, B4C and ZrSiO4 particulates reinforced with AA6063 composites were manufactured by stir casting technique. Mechanical properties of these composite materials were investigated by different weight percentages, 3%, 6%, 9% of boron carbide (B4C) and 9%, 6%, 3% of zirconium silicate (ZrSiO4) respectively. The mechanical properties evaluation reveals variations in hardness and the tensile strength values with the composite combinations investigated in this work. From the experimental studies, the optimum volume fraction of hybrid reinforcement in AA6063 alloy on the basis of mechanical properties and SEM analysis is also determined.


2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Arun Krishnan ◽  
L. Roy Xu

A special mechanics/material phenomenon involving nanocomposites is the agglomeration of nanofillers at high volume fractions of nanofillers. Numerous experimental investigations on nanocomposites have indicated a significant decrease in mechanical properties, due to the agglomeration of nanofillers. This paper describes a simple effective flaw model to correlate the local mechanical behavior of agglomerated nanoparticles with the change in global strengths of nanocomposites. The estimated bending strength reduction from our model is shown to be similar to experimental results reported by previous researchers. These results can be used as a guide for future nanocomposite design and development. Future nanomaterial manufacturing should be focused on eliminating the largest agglomerates, rather than limiting the nanofiller volume fraction. Meanwhile, by reducing the nanofiller agglomerate size, we expect that a high critical nanofiller volume fraction could be obtained to delay the mechanical property reduction.


2014 ◽  
Vol 804 ◽  
pp. 239-242
Author(s):  
Muhammad Asif ◽  
Zheng Yi Fu ◽  
Shahzad Ahmad Khan ◽  
Wei Min Wang ◽  
Hao Wang ◽  
...  

Fluoridated composite Hydroxyapatite biomaterial was prepared by sintering the hydroxyapatite Ca10 (PO4)6. (OH)2[HA] powder with addition of titanium fluoride 30 wt. % -TiF3 and mixture of iron oxide and aluminum oxide [5 wt. %-Al2O3/Fe2O3 ; (5/1)]. The pellets were prepared by conventional sol-gel technique. The as-prepared samples were sintered at various temperatures and the effect of different temperature on grain size and mechanical properties has been investigated. The samples were sintered at various temperatures of 1100-1400 °C. After sintering, the sample’s mechanical properties such as compressive strength, bending strength, Vickers hardness were improved to be 49±0.26-103±0.26 MPa, 19.6±0.20-36.2±0.20 MPa, and 7.97±0.16-12.50±0.16 GPa with their grains size 4.76±0.10-17.63±0.10 μm and bulk densities 1.8944-2.2426 g/cm3.


2022 ◽  
Vol 8 ◽  
Author(s):  
Sebastian Dahle ◽  
Kavyashree Srinivasa ◽  
Jure Žigon ◽  
Arnaud Maxime Cheumani Yona ◽  
Georg Avramidis ◽  
...  

The use of wood-based materials in building and construction is constantly increasing as environmental aspects and sustainability gain importance. For structural applications, however, there are many examples where hybrid material systems are needed to fulfil the specific mechanical requirements of the individual application. In particular, metal reinforcements are a common solution to enhance the mechanical properties of a wooden structural element. Metal-reinforced wood components further help to reduce cross-sectional sizes of load-bearing structures, improve the attachment of masonry or other materials, enhance the seismic safety and tremor dissipation capacity, as well as the durability of the structural elements in highly humid environments and under high permanent mechanical load. A critical factor to achieve these benefits, however, is the mechanical joint between the different material classes, namely the wood and metal parts. Currently, this joint is formed using epoxy or polyurethane (PU) adhesives, the former yielding highest mechanical strengths, whereas the latter presents a compromise between mechanical and economical constraints. Regarding sustainability and economic viability, the utilization of different adhesive systems would be preferable, whereas mechanical stabilities yielded for metal-wood joints do not permit for the use of other common adhesive systems in such structural applications. This study extends previous research on the use of non-thermal air plasma pretreatments for the formation of wood-metal joints. The plasma treatments of Norway spruce [Picea abies (L.) Karst.] wood and anodized (E6/EV1) aluminum AlMgSi0.5 (6060) F22 were optimized, using water contact angle measurements to determine the effect and homogeneity of plasma treatments. The adhesive bond strengths of plasma-pretreated and untreated specimens were tested with commercial 2-component epoxy, PU, melamine-urea formaldehyde (MUF), polyvinyl acetate (PVAc), and construction adhesive glue systems. The influence of plasma treatments on the mechanical performance of the compounds was evaluated for one selected glue system via bending strength tests. The impact of the hybrid interface between metal and wood was isolated for the tests by using five-layer laminates from three wood lamellae enclosing two aluminum plates, thereby excluding the influence of congeneric wood-wood bonds. The effect of the plasma treatments is discussed based on the chemical and physical modifications of the substrates and the respective interaction mechanisms with the glue systems.


2021 ◽  
Vol 113 ◽  
pp. 65-73
Author(s):  
Jakub Kawalerczyk ◽  
Marcin Kuliński ◽  
Dorota Dziurka ◽  
Radosław Mirski

The possibility to use a side-timber in glulam beams manufacturing for structural applications. The aim of presented study was to determine the mechanical properties of three-layered glued structural beams manufactured with the use of side-timber pieces as an outer layers and the fragmented main yield as an inner layer. Four types of beams were pressed and tested in terms of four-point bending strength and modulus of elasticity. Variants differed from each other in the direction of the fibers in the inner layer and in the presence of adhesive layer between the fragmented wood. Studies have shown that the bending strength of the beams depended on the calculation method. Moreover, no significant effect of the inner layer arranging method on the bending strength of the beams was found. The values of modulus of elasticity (MOE) were low. The presented study is a starting point for further investigations concerning the possible way of the rational application of fragmented timber pieces and the side-timber for structural applications.


There is a considerable variation in the mineralization of bone; normal, non-pathological compact bone has ash masses ranging from 45 to 85% by mass. This range of mineralization results in an even greater range of mechanical properties. The Young modulus of elasticity can range from 4 to 32 GPa, bending strength from 50 to 300 MPa, and the work of fracture from 200 to 7000 Jm -2 . It is not possible for any one type of bone to have high values for all three properties. Very high values of mineralization produce high values of Young modulus but low values of work of fracture (which is a measure of fracture toughness). Rather low values of mineralization are associated with high values of work of fracture but low values of Young modulus and intermediate values of bending strength. The reason for the high value for the Young modulus associated with high mineralization is intuitively obvious, but has not yet been rigorously modelled. The low fracture toughness associated with high mineralization may be caused by the failure of various crack-stopping mechanisms that can act when the mineral crystals in bone have not coalesced, but which become ineffective when the volume fraction of mineral becomes too high. The adoption of different degrees of mineralization by different bones, leading to different sets of mechanical properties, is shown to be adaptive in most cases studied, but some puzzles still remain.


2015 ◽  
Vol 799-800 ◽  
pp. 794-799 ◽  
Author(s):  
Sebti Jaballi ◽  
Imed Miraoui ◽  
Hedi Hassis

This paper focuses on the optimization of flexural strength and thermal conductivity of mortar reinforced with Alfa fibers. Fibers were manually extracted from Alfa leafs to avoid the risk of degradation of mechanical properties. A first group of samples (300 x 300 x 30 mm) having a fiber volume fraction of 0.5 to 1.5% is prepared to measure the thermal conductivity.The second composite family (40 x 40 x 160 mm) cured in a wet chamber is used for measuring its bending strength. The fiber percentage varies from 0.74 to 1,85%.The results show that the thermal conductivity decreases by increasing the fiber content. While the optimal percentage of fiber for the flexural strength is estimated at 1%, corresponding to an increase of 27% in strength.


Sign in / Sign up

Export Citation Format

Share Document