scholarly journals Bending Strength and Fracture Investigations of Cu Based Composite Materials Strengthened with δ-Alumina Fibres

2013 ◽  
Vol 13 (2) ◽  
pp. 59-63 ◽  
Author(s):  
J.W. Kaczmar ◽  
K. Granat ◽  
K. Naplocha ◽  
A. Kurzawa ◽  
E. Grodzka ◽  
...  
Keyword(s):  
Composite Materials ◽  
Elevated Temperatures ◽  
Bending Strength ◽  
Copper Matrix ◽  
Casting Method ◽  
Bending Tests ◽  
Three Point Bending ◽  
Infiltration Pressure ◽  
The Matrix ◽  
Fibre Matrix

Abstract Bending strength, thermal and electric conductivity and microstructure examinations of Cu based composite materials reinforced with Saffil alumina fibres are presented. Materials were produced by squeeze casting method applying the designed device and specially elaborated production parameters. Applying infiltration pressure of 90MPa and suitable temperature parameters provided manufacturing of copper based composite materials strengthened with Saffil alumina fibres characterized by the low rest porosity and good fibre-matrix interface. Three point bending tests at temperatures of 25, 100 and 300ºC were performed on specimens reinforced with 10, 15 and 20% of Saffil fibres. Introduced reinforcement effected on the relatively high bending strengths at elevated temperatures. In relation to unreinforced Cu casting strength of composite material Cu - 15vol.% Saffil fibres increase by about 25%, whereas at the highest applied test temperature of 300oC the improvement was almost 100%. Fibres by strengthening of the copper matrix and by transferring loads from the matrix reduce its plastic deformation and hinder the micro-crack developed during bending tests. Decreasing of thermal and electrical conductivity of Cu after incorporating fibres in the matrix are relatively small and these properties can be acceptable for electric and thermal applications.

Effects on the Bending Strength of Metal-Bonded Diamond Segments in DEM Simulation

2011 ◽  
Vol 175 ◽  
pp. 201-205 ◽  
Author(s):  
Xiu Yu Chen ◽  
Yi Qing Yu ◽  
Xi Peng Xu
Keyword(s):  
Metal Matrix ◽  
Bending Strength ◽  
Connection Strength ◽  
Dem Simulation ◽  
Bending Tests ◽  
Abrasive Particles ◽  
Three Point Bending ◽  
The Matrix ◽  
The Coefficient Of Friction ◽  
Matrix Components

An attempt was taken to simulate the bending strength of diamond impregnated segments in three point bending tests by using a discrete element method (DEM). The influences of main bond matrix components (Fe and Cu), the porosity in the matrix, the coefficient of friction among the matrix particles, and the connection strength between abrasive particles and matrix particles on the bending strength were investigated through simulation. It is found that the bending strength increases with the proportion of Fe but decreases with the increase of porosity. An increase in both the friction coefficient of the matrix particles and the bonding strength between the diamond grains and metal matrix particles can also lead to the increase of bending strength.

scholarly journals Chlorine-Functional Silsesquioxanes (POSS-Cl) as Effective Flame Retardants and Reinforcing Additives for Rigid Polyurethane Foams

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3979
Author(s):  
Anna Strąkowska ◽  
Sylwia Członka ◽  
Karolina Miedzińska ◽  
Krzysztof Strzelec
Keyword(s):  
Flame Retardants ◽  
Elevated Temperatures ◽  
Bending Strength ◽  
Reaction System ◽  
Fire Retardant ◽  
Polyurethane Foams ◽  
Polymerization Reaction ◽  
Three Point Bending ◽  
One Step

The subject of the research was the production of silsesquioxane modified rigid polyurethane (PUR) foams (POSS-Cl) with chlorine functional groups (chlorobenzyl, chloropropyl, chlorobenzylethyl) characterized by reduced flammability. The foams were prepared in a one-step additive polymerization reaction of isocyanates with polyols, and the POSS modifier was added to the reaction system in an amount of 2 wt.% polyol. The influence of POSS was analyzed by performing a series of tests, such as determination of the kinetics of foam growth, determination of apparent density, and structure analysis. Compressive strength, three-point bending strength, hardness, and shape stability at reduced and elevated temperatures were tested, and the hydrophobicity of the surface was determined. The most important measurement was the determination of the thermal stability (TGA) and the flammability of the modified systems using a cone calorimeter. The obtained results, after comparing with the results for unmodified foam, showed a large influence of POSS modifiers on the functional properties, especially thermal and fire-retardant, of the obtained PUR-POSS-Cl systems.

scholarly journals Rocess Design of Fiber Reinforced Magnesium Matrix Composites

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Ding Hualun
Keyword(s):  
Composite Materials ◽  
Matrix Composites ◽  
Deposition Method ◽  
Fiber Reinforced ◽  
Casting Method ◽  
Magnesium Matrix ◽  
Preparation Methods ◽  
Magnesium Matrix Composites ◽  
The Matrix ◽  
And Performance

This paper chooses magnesium as the matrix of composite materials, selects carbon fi ber as reinforcement, anddesigns the composite scheme according to the structure and performance of Mg-based composites. The performancecharacteristics and application prospect of fiber-reinforced magnesium matrix composites are introduced. Wait. Inthis paper, the process of preparing carbon fi ber magnesium matrix composites by compression casting method andspray deposition method is designed. The process fl ow chart of these two design schemes is determined by analyzingthe principle of these two kinds of preparation methods, and the specifi c problems of the process are analyzed andsummarized.

CORRELATION DEPENDENCES OF THE BENDING STRENGTH OF POLYMER COMPOSITE MATERIALS MODIFIED IN A MICROWAVE ELECTROMAGNETIC FIELD ON THE MOISTURE CONTENT DURING EXPOSURE IN FULL-SCALE CONDITIONS

2021 ◽  
pp. 3-9
Author(s):  
I. V. Zlobina ◽  
I. S. Katsuba
Keyword(s):  
Electromagnetic Field ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Moisture Content ◽  
Bending Strength ◽  
Climatic Factors ◽  
Experimental Studies ◽  
Three Point Bending ◽  
Treated Carbon ◽  
Control Samples

Experimental studies of the influence of external climatic factors, taking into account exposure, on the change in the bending strength of control and microwave – treated carbon and fiberglass samples in the cured state were performed. An increase in the limit stresses of three – point bending of experimental carbon fiber samples compared to the control ones was found by 7…12 %, and fiberglassby 4…7 %. It is shown that with an increase in exposure to 14 months, the strength of control samples of carbon and fiberglass decreases by an average of 10 %. At the same time, the strength of the prototypes is reduced only by 4.4 %. With an increase in the moisture content of both control and experimental samples, a decrease in their strength is observed. In this case, the linear correlation is average (from– 0.44 to – 0.615). It is established that for experimental samples, the influence of the amount of absorbed moisture on the strength is manifested to a much lesser extent. For carbon fiber, the reduction is 16.6 %, for fiberglass – 12 %.

Bending Strength of Al2O3 Ceramics for Textiles Machinery and Elastic Wave Characteristics by Wavelet Analysis

2007 ◽  
Vol 353-358 ◽  
pp. 345-348
Author(s):  
Ki Woo Nam ◽  
B.G. Ahn ◽  
M.K. Kim ◽  
C.S. Son ◽  
Jin Wook Kim ◽  
...  
Keyword(s):  
Elastic Wave ◽  
Bending Strength ◽  
Test Results ◽  
Composite Ceramics ◽  
Bending Tests ◽  
Three Point Bending ◽  
Wave Signal ◽  
Al2o3 Composite ◽  
Signal Characteristics ◽  
Optimized Conditions

The optimized conditions of pressureless sintering were investigated in order to obtain the bending strength and the elastic wave signal of Al2O3 composite ceramics for textiles machinery. As sintering conditions, a temperature range from 1400°C to 1700°C and time from 30 minutes to 150 minutes were applied. Three-point bending tests were conducted on the sintered materials to obtain the strength property. From the test results, the optimum sintering condition was 1600°C, 100 minutes. Al2O3 composite ceramics showed that the elastic wave signal characteristics had a regular correlativity between the optimum sintering temperature and time as well as the maximum bending strength.

Fabrication of Composite Blocks Containing Alumina Bubble Particles for Porous CBN Abrasive Wheels

2012 ◽  
Vol 499 ◽  
pp. 229-234 ◽  
Author(s):  
Q. Pan ◽  
Wen Feng Ding ◽  
Jiu Hua Xu ◽  
B. Zhang ◽  
H.H. Su ◽  
...  
Keyword(s):  
Fracture Surface ◽  
Dwell Time ◽  
Bending Strength ◽  
Ti Alloy ◽  
Abrasive Wheel ◽  
Bending Tests ◽  
Three Point Bending ◽  
Abrasive Grains ◽  
Alumina Particles ◽  
Vitrified Cbn

Alumina (Al2O3) bubble particles were added into the mixture of CBN abrasive grains, Cu-Sn-Ti alloy and graphite particles to prepare the composite blocks for porous CBN abrasive wheels. The specimens were sintered at the temperature of 920°C for the dwell time of 30 min. The bending strength of the composite blocks was measured by the three-point bending tests. The fracture surface of the blocks was characterized. The results show that, the content of alumina bubble particles does not take significant effect on the mechanical strength of the composite blocks. Even the lowest strength of the composite blocks, 98 MPa, is higher than that of the vitrified CBN abra-sive wheels. Cu-Sn-Ti alloy has bonded firmly alumina particles and CBN grains by means of the chemical reaction and corresponding products. Finally, the chip space was formed through the re-moval of the ceramic wall of the alumina bubble particles within the CBN abrasive wheel during dressing.

scholarly journals Influence of the Infill Orientation on the Properties of Zirconia Parts Produced by Fused Filament Fabrication

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3158 ◽  
Author(s):  
Santiago Cano ◽  
Tanja Lube ◽  
Philipp Huber ◽  
Alberto Gallego ◽  
Juan Alfonso Naranjo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Complex Geometries ◽  
Fused Filament Fabrication ◽  
Moisture Evaporation ◽  
Bending Tests ◽  
Three Point Bending ◽  
Different Types ◽  
Fill Pattern ◽  
The Many

The fused filament fabrication (FFF) of ceramics enables the additive manufacturing of components with complex geometries for many applications like tooling or prototyping. Nevertheless, due to the many factors involved in the process, it is difficult to separate the effect of the different parameters on the final properties of the FFF parts, which hinders the expansion of the technology. In this paper, the effect of the fill pattern used during FFF on the defects and the mechanical properties of zirconia components is evaluated. The zirconia-filled filaments were produced from scratch, characterized by different methods and used in the FFF of bending bars with infill orientations of 0°, ±45° and 90° with respect to the longest dimension of the specimens. Three-point bending tests were conducted on the specimens with the side in contact with the build platform under tensile loads. Next, the defects were identified with cuts in different sections. During the shaping by FFF, pores appeared inside the extruded roads due to binder degradation and or moisture evaporation. The changes in the fill pattern resulted in different types of porosity and defects in the first layer, with the latter leading to earlier fracture of the components. Due to these variations, the specimens with the 0° infill orientation had the lowest porosity and the highest bending strength, followed by the specimens with ±45° infill orientation and finally by those with 90° infill orientation.

Effect of Moisture Absorption on the Bending Strength of CFRP

2012 ◽  
Vol 450-451 ◽  
pp. 482-485 ◽  
Author(s):  
A Ying Zhang ◽  
Di Hong Li ◽  
Dong Xing Zhang
Keyword(s):  
Moisture Content ◽  
Composite Laminates ◽  
Immersion Time ◽  
Moisture Absorption ◽  
Bending Strength ◽  
Experimental Results ◽  
Bending Tests ◽  
Three Point Bending ◽  
Damage Propagation ◽  
Effect Of Moisture

The effects of moisture content on the bending strength of T300/914 composite laminates that immersed in water for 7 days and 14 days was discussed in this paper. The three-point bending tests were conducted on the composite laminates. Experimental results reveal that the moisture content in the laminates increased with immersion time and that moisture absorption accelerated damage propagation in the composite laminates. The bending strength of the unaged, aged specimens were characterized and analyzed. Compared to the unaged specimens, the bending strength of the composite laminates immersed for 7 and 14 days decreased by 6.62% and 16.98%, respectively. The results revealed that the bending strength of the aged specimens decreased with the increasing immersion time.

scholarly journals Impact Strength of Composite Materials Based on EN AC-44200 Matrix Reinforced with Al2O3 Particles

2017 ◽  
Vol 17 (3) ◽  
pp. 73-78 ◽  
Author(s):  
A. Kurzawa ◽  
J.W. Kaczmar
Keyword(s):  
Composite Materials ◽  
Impact Strength ◽  
Elevated Temperatures ◽  
Al Alloy ◽  
Pressure Infiltration ◽  
Reinforcing Particles ◽  
Strength Based ◽  
Crack Mechanics ◽  
The Matrix ◽  
Microscopic Studies

AbstractThe paper presents the results of research of impact strength of aluminum alloy EN AC-44200 based composite materials reinforced with alumina particles. The research was carried out applying the materials produced by the pressure infiltration method of ceramic preforms made of Al2O3particles of 3-6μm with the liquid EN AC-44200 Al alloy. The research was aimed at determining the composite resistance to dynamic loads, taking into account the volume of reinforcing particles (from 10 to 40% by volume) at an ambient of 23°C and at elevated temperatures to a maximum of 300°C. The results of this study were referred to the unreinforced matrix EN AC-44200 and to its hardness and tensile strength. Based on microscopic studies, an analysis and description of crack mechanics of the tested materials were performed. Structural analysis of a fracture surface, material structures under the crack surfaces of the matrix and cracking of the reinforcing particles were performed.

Bending Properties and Failure Mechanisms of Tapered 3D Braided Composites

2011 ◽  
Vol 332-334 ◽  
pp. 1468-1471 ◽  
Author(s):  
Can Can Cheng ◽  
Zhao Lin Liu ◽  
Li Fang Liu ◽  
Jian Yong Yu
Keyword(s):  
Failure Modes ◽  
Bending Strength ◽  
Failure Mechanisms ◽  
Reduction Technique ◽  
Braided Composites ◽  
Bending Properties ◽  
Bending Tests ◽  
Three Point Bending ◽  
Bending Modulus ◽  
3D Braided Composites

Tapered 3D braided composites are prepared by column yarn-reduction technique, unit yarn-reduction technique and cutting, respectively. Bending properties in the tapered regions of the composites are obtained by three-point bending tests, and SEM photographs of the fracture surfaces are observed to analyze the failure mechanisms. Results show that bending modulus and bending strength of the yarn-reduction composites are significantly higher than those of the cut composites, and the unit yarn-reduction composites are slightly stronger than the column yarn-reduction composites. The saw-tooth propagation of matrix crackings and interfacial debondings are the primary failure mechanisms of the yarn-reduction composites, while yarn breakages and yarn pulling-outs are the main failure modes of the cut composites.

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