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1

Mechanical property evaluation aluminium 6061 nickel coated cenosphere composites

Ahamed A., Prashanth T.

Mechanics and Mechanical Engineering

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2018

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Vol. 22, nr 4

1381--1388

EN

In recent years, among all the aluminium alloys, Al6061 is gaining much popularity as a matrix material to prepare MMCs owing to its excellent mechanical properties and good corrosion resistance. Fly ash cenospheres are primarily a by-product in power generation plants. Research is in progress to effectively use this byproduct to produce new usable and profitable materials as they pose major disposal and environmental problems. In the light of the above, the present investigation is aimed at development of metal coated cenosphere reinforced Al6061 composites and to characterize their mechanical properties. Al6061 nickel coated composites have been prepared by liquid metallurgy route by varying percentage of nickel coated cenospheres between 2-10% by weight in steps of 2%. Density, hardness and tensile behaviour of the composites is carried out. It is observed that there is an increase in the values of hardness, density of the composite with an increasing percentage of the nickel coated cenosphere reinforcements. There is also a notable increase in the tensile strength as well as reduction in ductility of the prepared composite. Fractographs to indicate the behaviour of the composites have also been depicted in the paper.

2

Effect of Repeated Austenitisation and Cooling on the Microstructure, Hardness and Tensile Behaviour of 0.16 wt % Carbon Steel

Subhani A. R., Mondal D. K.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 3

1141--1152

EN

Repeated austenitisation and furnace cooling of homogenised 0.16 wt. % carbon steels result in ferrite grain sizes between 27 μm and 24 μm. Similarly, repeated austenitisation and normal-air cooling produces ferrite grain sizes between 17 μm and 12 μm; while repeated austenitisation and forced-air cooling produces a minimum grain size of 9.5 μm. Furnace cooling decomposes the austenite eutectoidally to lamellar pearlite; while normal-air cooling and forced-air cooling after austenitisation cause degen eration of pearlite regions producing grain boundary network as well as cluster of cementite and other carbides. Forced-air cooled samp les provide the highest YS (364 MPa) and UTS (520 MPa); while furnace cooling provides the lowest (290 MPa and 464 MPa) leaving the normal-air cool performance in between. Hardness values depict the role of individual ferrite and pearlite content and the extent of pearlite degeneration occurring after each cyclic treatment.

3

The effect of welding defects to the tensile behavior in corrosive environment of AISI 304L stainless steel joined with shielded metal electrode

Türkan M., Karakaş Ö.

Journal of Achievements in Materials and Manufacturing Engineering

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2017

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Vol. 85, nr 1

26--30

EN

Purpose: Determination of the tensile behavior of welded constructions made of austenitic stainless steel in corrosive environments is of great importance for the safer use of the construction. When austenitic stainless steels are welded together, welding defects can occur in some cases. And stainless steels are used in corrosive environments. Thus, we are aimed to investigate the effect of welding defects the tensile behavior in corrosive environment of AISI 304 L stainless steel joined with shielded metal electrode. Design/methodology/approach: Hardness measurements and micro-macro structures examination were made before the corrosion test to characterize the structure of the weld zone. Corrosion tests were carried out in accordance with EN ISO 9227 by exposing the welded tensile specimens to salt spray for 24-96-240-480-720-1000 hours. After the salt spray test, tensile tests were performed. The fractured surfaces were examined following the tensile tests by scanning electron microscope (SEM). Findings: A significant decrease in the tensile strength of the material was observed with the increase of the salt spraying period as a result of the tests. It is worth noting that corrosion products were occurred especially in the areas of welding defects. Research limitations/implications: This study was performed on materials containing welding defects. In addition, the corrosive environment was provided by salt spraying. It should not be forgotten that the materials may behave differently in different corrosive environments. Originality/value: While there are studies regarding effects of welding defects and corrosion individually, no study has been found in the literature which considers the effect of welding defects within corrosive environments on the material strength. Therefore, this study presents novel findings by considering both detrimental effects at the same time. The study shows significant decrease in strength of the material due to welding defects and corrosive environment.

4

Finite Element Modelling for Tensile Behaviour of Thermally Bonded Nonwoven Fabric

Gao X., Wang L.

Autex Research Journal

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2015

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Vol. 15, no. 1

48--53

EN

A nonwoven fabric has been widely used in geotextile engineering in recent years; its tensile strength is an important behaviour. Since the fibre distributions in nonwoven fabrics are random and discontinuous, the unit-cell model of a nonwoven fabric cannot be developed to simulate its tensile behaviour. This article presents our research on using finite element method (FEM) to study the tensile behaviour of a nonwoven fabric in macro-scale based on the classical laminate composite theory. The laminate orientation was considered with orientation distribution function of fibres, which has been obtained by analysing the data acquired from scanning electron microscopy with Hough Transform. The FE model of a nonwoven fabric was developed using ABAQUS software; the required engineering constants of a nonwoven fabric were obtained from experimental data. Finally, the nonwoven specimens were stretched along with machine direction and cross direction. The experimental stress-strain curves were compared with the results of FE simulations. The approximate agreement proves the validity of an FE model, which could be used to precisely simulate the stress relaxation, strain creep, bending and shear property of a nonwoven fabric.

5

Prediction of formability of adhesive bonded steel sheets and experimental validation

Satheeshkumar V., Ganesh Narayanan R.

Archives of Civil and Mechanical Engineering

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2015

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Vol. 15, no. 1

30--41

EN

The main aim of the present work is to predict the formability of adhesive bonded sheets and validate the same with experimental results at different adhesive properties. The tensile and in-plane plane-strain formability tests are carried out to predict the formability of adhesive bonded sheets. The forming limit strains are predicted using thickness gradient necking criterion (TGNC) and effective strain rate criterion (ESRC), and validated with the experimental limit strains. A simulation methodology has been analyzed thoroughly in the present work, and the prediction accuracies are compared and discussed. The results show that the adhesive bonded blanks show improved elongation and forming limit strains as compared to un-bonded base materials with increase in hardener/resin ratio of adhesive. The true stress–strain predictions are accurate as compared to experimental data. There is a moderate difference in adhesive bonded sheets limit strains between predictions and experiments. This may be due to the absence of interface bonding between adhesive and base materials during predictions. The necking criterion, TGNC, shows better prediction as compared to ESRC.

6

Effect of processing parameters on the tensile behavior of laminated composites synthesized using titanium and aluminum foils

Konieczny M., Szwed B.

Journal of Achievements in Materials and Manufacturing Engineering

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2014

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Vol. 66, nr 2

61--66

EN

Purpose: This study describe effect of processing parameters on the tensile behaviour of laminated composites synthesized using titanium and aluminium foils. Design/methodology/approach: 50, 100 and 150 μm thick titanium and 50 μm thick aluminium foils have been used to fabricate Ti-Al3Ti and Ti-(Al3Ti+Al) composites. These laminated materials were synthesized in vacuum with controlled treating time and temperature. All composites were synthesized at 650°C. Treating time was a main factor determining the composition and tensile behaviour of the composites. Tensile tests were performed on the materials with different microstructures to establish their properties and fracture behaviour. Findings: Since the examinations showed that Al3Ti was the only intermetallic phase formed during the reaction between titanium and aluminium, the initial foil thicknesses affected only the volume fraction of the resultant Ti, Al and Al3Ti layers. Aluminium layers reacted completely after 60 minutes resulting in microstructures with Ti residual layers alternating with the Al3Ti layers. After 60 minutes of treating all composites had higher yield strength and higher ultimate tensile strength than composites after 20 minutes of treating produced with the same thickness of starting Ti foil. On the other hand, strain at fracture behaved conversely. Research limitations/implications: The results of investigations indicated that tensile behaviour of the composites depended strongly on the thickness of individual Ti layers and the presence of residual Al layers at the intermetallic centrelines. Originality/value: In the present study, the reaction synthesis was employed to fabricate laminated composites in vacuum using Ti foils with different original thicknesses and Al foils with one constant thickness.

7

Experimental Study on the Mechanic Behaviour of Weft Knitted Fabrics

Ciobanu L., Filipescu F.

Fibres & Textiles in Eastern Europe

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2012

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Vol. 20, no. 2 (91)

34-39

EN

The paper presents the results of an extensive investigation regarding the tensile behaviour of knitted fabrics with basic evolutions, made of two types of yarns: classic acrylic yarn (used for garments) and PES HT yarn (used for technical applications). Samples were produced according to an experimental matrix containing technological variables considered significant. The fabrics were tested for tensile strain in both the weft and warp directions, and the values were compared and discussed. Conclusions regarding the tensile behaviour of weft knitted fabrics are drawn based on the experimental data.

PL

Badano właściwości wytrzymałościowe dzianin rządkowych wykonanych z dwóch typów przędz - klasycznych: przędz akrylowych używanych do produkcji wyrobów odzieżowych oraz wysoko wytrzymałych przędz poliestrowych używanych do wyrobów technicznych. Próbki wykonano na podstawie opracowanej macierzy zawierającej zmienne wielkości procesu technologicznego. Badano wytrzymałość uzyskanych próbek zarówno w kierunku osnowy jak i wątku. Na podstawie porównania i analizy wyników opracowano wnioski dotyczące wytrzymałości dzianin.

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Studies on corn starch filled poly (styrene-co-butyl acrylate) latex reinforced polyester nonwoven fabric composites

Satheesh Kumar M. N., Siddaramaiah

Autex Research Journal

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2005

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Vol. 5, no. 4

228--235

EN

Poly (styrene-co-butyl acrylate) latex was prepared with a 70:30 weight ratio of styrene to butyl acrylate. Various weight percentages of cornstarch were incorporated into the prepared copolymer latex. Polyester nonwoven fabric reinforced-cornstarch-filled copolymer latex composites were manufactured by the impregnation method. The pickup ratio of latex to fabric was maintained at 3.2:1. The composites' physico-mechanical properties, percent water absorption and percent thickness swelling were studied. The manufactured cornstarch-filled composites were evaluated for their ability to retain their shape after being moulded to the desired shape by measuring the percentage area, shape retention, hardness and resilience. It was observed that the manufactured thermoplastic composite specimens retained or increased their mechanical properties up to 20 wt% cornstarch loading.