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1

Three Point Bending Behavior of Woven Glass, Aramid and Carbon Fiber Reinforced Hybrid Composite Tube

100%

Ekşi S., Genel K.

Acta Physica Polonica A

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2015

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vol. 128

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issue 2B

B-59-B-61

EN

In this study, bending behavior of hybrid composites reinforced by different type of fibers is investigated experimentally. In the preparation of composite samples with different number of layers having the same thickness and woven shaped glass, aramid and carbon fibers are used and three-point bending test is carried out to determine bending behavior. It is seen from the test results that, regardless of fiber type, the load bearing capacity and energy absorption capability are increased by increasing layer number. As a result of evaluation of hybrid composites containing different fibers with respect of load-carrying capability and energy absorbing capacity, aramid-fiber reinforced composite with 2 and 4 layer provides better performance. T+2GF+2CF+2AF specimen can be preferred in between 10 layered hybrid tubes and T+2GF+2AF+6CF and T+2GF+2CF+6AF specimens in 10 layered hybrid tubes. Load carrying capacity of hybrid tubes increased 7 times and energy absorbing capacity 9.6 times, respectively.

2

Fabrication and Characterization of Tensile Deformation of Tin-Lead Open Cell Foams

100%

Belhadj A., Azzaz M., Abudura S.

Acta Physica Polonica A

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2015

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vol. 128

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issue 4

615-618

EN

This study is devoted to the investigation of metallic foams based on tin-lead alloy (with 50% of tin content) by the liquid metal infiltration process. Uniaxial tensile tests were performed at room temperature in order to study mechanical properties of foams of different relative density and cell size. The samples were concurrently characterized on a microscopic scale (metallography and hardness) in order to link the morphological and mechanical characteristics of the constitutive phases.

3

The Very High Cycle Fatigue Behaviour of Ti-6Al-4V Alloy

100%

Janeček M., Nový F., Harcuba P., Stráský J., Trško L., Mhaede M., Wagner L.

Acta Physica Polonica A

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2015

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vol. 128

|

issue 4

497-502

EN

The high cycle and very high cycle fatigue properties of the titanium alloy Ti-6Al-4V with a duplex microstructure were investigated at room temperature. High cycle fatigue tests were performed in the range from 10⁴ to 10⁷ cycles by rotating bending at the frequency of 30 Hz. The very high cycle fatigue tests were carried out in the range from 10⁷ to 10¹⁰ cycles in tension-compression on an ultrasonic fatigue testing machine at the frequency of 20 kHz. The stress amplitude was found to decrease with increasing number of cycles in the whole range from 10⁴ up to 10⁹ cycles and only at the highest number of cycles (N_{F}=10⁹) the alloy exhibits the fatigue limit of 460 MPa. The detail fractographic analysis was performed to characterize the fatigue failure mechanisms. Both subsurface and surface crack initiation were observed in very high cycle fatigue region. No inclusions, but only local chemical inhomogeneity in microstructure was observed at the locations of subsurface fatigue crack initiation in alpha-grains.

4

Comparison of Hardness and Wear Behaviour οf Boronized and Carburized AISI 8620 Steels

100%

Calik A., Duzgun A., Ekinci A., Karakas S., Ucar N.

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EN

In this study, the hardness and wear behaviour of carburized and boronized AISI 8620 steels have been studied. The boronizing treatment increased the hardness of AISI 8620 steels from 395 HV_{0.1} to a maximal 1610 HV_{0.1} compared to the carburized steels and also significantly improved its wear behaviour. From obtained results, it can be concluded that boronizing is very effective surface hardening method for improving the wear properties of AISI 8620 steels.

5

Formability Evaluation of Aluminium Alloys by FLD Diagrams

88%

Petroušek P., Kočiško R., Kvačkaj T., Bidulský R., Bidulská J., Fedoriková A., Sabol P.

Acta Physica Polonica A

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2017

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vol. 131

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issue 5

1344-1346

EN

The goal of the present work is evaluated mechanical properties and forming limit diagrams of ambient rolled aluminium alloy based on AlMgSi. Forming limit diagrams are convenient and often used as a tool for the classification of the formability and the evaluation of the forming process of sheet materials. Forming limits of sheet metal are represented in the forming limit diagrams occurring by various deformation states. The most widely used type is the Keeler-Goodwin diagram. Input data got from static tensile test are important for formability evaluating of the thin sheet by mathematical simulations, such as tensile strength, yield strength, elongation, and the strain hardening exponent. The result is a consideration of the suitability of the material for stamping technology.

6

Influence of Pre-Compression on Tensile Behaviour in Wrought Mg-Zn-Ce Alloy Studied by the Acoustic Emission Technique

88%

Dobroň P., Drozdenko D., Bohlen J., Yi S., Letzig D., Chmelík F.

Acta Physica Polonica A

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2015

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vol. 128

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issue 4

790-794

EN

Wrought Mg-Zn-Ce alloy (ZE10) has been pre-compressed and subsequently subjected to tensile loading. Due to a fibre texture of the samples, the level of pre-compression stress significantly influences the subsequent tensile behaviour. The acoustic emission technique was used for monitoring active deformation mechanisms during mechanical testing. The obtained acoustic emission results are correlated to the stress-time curves and the differences in the acoustic emission count rate were used to reveal changes in underlying deformation mechanisms. Firstly, a compression-tension cycle was monitored by the acoustic emission technique. Then, the samples were deformed to specific points on the stress-time curve, where acoustic emission exhibits strong changes in the activity. The following microstructure analysis of the samples, deformed to different strain-levels, by using electron back scattered diffraction method brought a detailed insight into active deformation mechanisms. Twinning during the pre-compression was followed by detwinning during the tensile loading. Two consecutive acoustic emission peaks, which appeared at larger strains, are explained by interplay of detwinning and dislocation slip and a nucleation of compression twins, respectively.

7

Microstructure and Properties of Spark Plasma Sintered Al-Zn-Mg-Cu Alloy

75%

Becker H., Dopita M., Stráská J., Málek P., Vilémová M., Rafaja D.

Acta Physica Polonica A

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2015

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vol. 128

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issue 4

602-605

EN

The microstructure of an aluminum alloy containing 53 wt% Zn, 2.1 wt% Mg and 1.3 wt% Cu as main alloying elements has been studied with the focus on the precipitation behavior during the spark plasma sintering process. The starting material was an atomized Al-Zn-Mg-Cu powder with the particle size below 50 μm. The particles showed a solidification microstructure from cellular to columnar or equiaxed dendritic morphology with a large fraction of the alloying elements segregated in form of intermetallic phases, mainly (Zn,Al,Cu)₄₉Mg₃₂ and Mg₂(Zn,Al,Cu)₁₁, at the cell and dendrite boundaries. The microstructure of the sintered specimens followed the microstructure of the initial powder. However, Mg(Zn,Al,Cu)₂ precipitates evolve at the expense of the initial precipitate phases. The precipitates which were initially continuously distributed along the intercellular and interdendritic boundaries form discrete chain-like structures in the sintered samples. Additionally, fine precipitates created during the sintering process evolve at the new low-angle boundaries. The large fraction of precipitates at the grain boundaries and especially at the former particle boundaries could not be solved into the matrix applying a usual solid solution heat treatment. A bending test reveals low ductility and strength. The mechanical properties suffer from the precipitates at former particle boundaries leading to fracture after an outer fiber tensile strain of 3.8%.

Refine search results

Three Point Bending Behavior of Woven Glass, Aramid and Carbon Fiber Reinforced Hybrid Composite Tube

Fabrication and Characterization of Tensile Deformation of Tin-Lead Open Cell Foams

The Very High Cycle Fatigue Behaviour of Ti-6Al-4V Alloy

Comparison of Hardness and Wear Behaviour οf Boronized and Carburized AISI 8620 Steels

Formability Evaluation of Aluminium Alloys by FLD Diagrams

Influence of Pre-Compression on Tensile Behaviour in Wrought Mg-Zn-Ce Alloy Studied by the Acoustic Emission Technique

Microstructure and Properties of Spark Plasma Sintered Al-Zn-Mg-Cu Alloy