Search results

1 – 10 of over 24000
To view the access options for this content please click here
Article
Publication date: 2 August 2021

Modupeola Dada, Patricia Popoola and Ntombi Mathe

This study aims to review the recent advancements in high entropy alloys (HEAs) called high entropy materials, including high entropy superalloys which are current…

Abstract

Purpose

This study aims to review the recent advancements in high entropy alloys (HEAs) called high entropy materials, including high entropy superalloys which are current potential alternatives to nickel superalloys for gas turbine applications. Understandings of the laser surface modification techniques of the HEA are discussed whilst future recommendations and remedies to manufacturing challenges via laser are outlined.

Design/methodology/approach

Materials used for high-pressure gas turbine engine applications must be able to withstand severe environmentally induced degradation, mechanical, thermal loads and general extreme conditions caused by hot corrosive gases, high-temperature oxidation and stress. Over the years, Nickel-based superalloys with elevated temperature rupture and creep resistance, excellent lifetime expectancy and solution strengthening L12 and γ´ precipitate used for turbine engine applications. However, the superalloy’s density, low creep strength, poor thermal conductivity, difficulty in machining and low fatigue resistance demands the innovation of new advanced materials.

Findings

HEAs is one of the most frequently investigated advanced materials, attributed to their configurational complexity and properties reported to exceed conventional materials. Thus, owing to their characteristic feature of the high entropy effect, several other materials have emerged to become potential solutions for several functional and structural applications in the aerospace industry. In a previous study, research contributions show that defects are associated with conventional manufacturing processes of HEAs; therefore, this study investigates new advances in the laser-based manufacturing and surface modification techniques of HEA.

Research limitations/implications

The AlxCoCrCuFeNi HEA system, particularly the Al0.5CoCrCuFeNi HEA has been extensively studied, attributed to its mechanical and physical properties exceeding that of pure metals for aerospace turbine engine applications and the advances in the fabrication and surface modification processes of the alloy was outlined to show the latest developments focusing only on laser-based manufacturing processing due to its many advantages.

Originality/value

It is evident that high entropy materials are a potential innovative alternative to conventional superalloys for turbine engine applications via laser additive manufacturing.

Details

World Journal of Engineering, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1708-5284

Keywords

To view the access options for this content please click here
Article
Publication date: 1 December 2004

George K. Stylios

Examines the tenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects…

Downloads
2771

Abstract

Examines the tenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.

Details

International Journal of Clothing Science and Technology, vol. 16 no. 6
Type: Research Article
ISSN: 0955-6222

Keywords

To view the access options for this content please click here
Article
Publication date: 26 April 2011

A.B. Spierings, N. Herres and G. Levy

A recent study confirmed that the particle size distribution of a metallic powder material has a major influence on the density of a part produced by selective laser…

Downloads
4602

Abstract

Purpose

A recent study confirmed that the particle size distribution of a metallic powder material has a major influence on the density of a part produced by selective laser melting (SLM). Although it is possible to get high density values with different powder types, the processing parameters have to be adjusted accordingly, affecting the process productivity. However, the particle size distribution does not only affect the density but also the surface quality and the mechanical properties of the parts. The purpose of this paper is to investigate the effect of three different powder granulations on the resulting part density, surface quality and mechanical properties of the materials produced.

Design/methodology/approach

The scan surface quality and mechanical properties of three different particle size distributions and two layer thicknesses of 30 and 45 μm were compared. The scan velocities for the different powder types have been adjusted in order to guarantee a part density≥99.5 per cent.

Findings

By using an optimised powder material, a low surface roughness can be obtained. A subsequent blasting process can further improve the surface roughness for all powder materials used in this study, although this does not change the ranking of the powders with respect to the resulting surface quality. Furthermore, optimised powder granulations lead generally to improved mechanical properties.

Practical implications

The results of this study indicate that the particle size distribution influences the quality of AM metallic parts, produced by SLM. Therefore, it is recommended that any standardisation initiative like ASTM F42 should develop guidelines for powder materials for AM processes. Furthermore, during production, the granulation changes due to spatters. Appropriate quality systems have to be developed.

Originality/value

The paper clearly shows that the particle size distribution plays an important role regarding density, surface quality and resulting mechanical properties.

Details

Rapid Prototyping Journal, vol. 17 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 1 December 2002

George K. Stylios

Looks at the eighth published year of the ITCRR and the research, from far and near, involved in this. Muses on the fact that, though all the usual processes are to the…

Abstract

Looks at the eighth published year of the ITCRR and the research, from far and near, involved in this. Muses on the fact that, though all the usual processes are to the fore, the downside part of the industry is garment making which is the least developed side. Posits that the manufacture of clothing needs to become more technologically advanced as does retailing. Closes by emphasising support for the community in all its efforts.

Details

International Journal of Clothing Science and Technology, vol. 14 no. 6
Type: Research Article
ISSN: 0955-6222

Keywords

To view the access options for this content please click here
Article
Publication date: 9 March 2015

Mumin Sahin, Cenk Misirli and Dervis Özkan

– The purpose of this paper is to examine mechanical and metallurgical properties of AlTiN- and TiN-coates high-speed steel (HSS) materials in detail.

Abstract

Purpose

The purpose of this paper is to examine mechanical and metallurgical properties of AlTiN- and TiN-coates high-speed steel (HSS) materials in detail.

Design/methodology/approach

In this study, HSS steel parts have been processed through machining and have been coated with AlTiN and TiN on physical vapour deposition workbench at approximately 6,500°C for 4 hours. Tensile strength, fatigue strength, hardness tests for AlTiN- and TiN-coated HSS samples have been performed; moreover, energy dispersive X-ray spectroscopy and X-ray diffraction analysis and microstructure analysis have been made by scanning electron microscopy. The obtained results have been compared with uncoated HSS components.

Findings

It was found that tensile strength of TiAlN- and TiN-coated HSS parts is higher than that of uncoated HSS parts. Highest tensile strength has been obtained from TiN-coated HSS parts. Number of cycles for failure of TiAlN- and TiN-coated HSS parts is higher than that for HSS parts. Particularly TiN-coated HSS parts have the most valuable fatigue results. However, surface roughness of fatigue samples may cause notch effect. For this reason, surface roughness of coated HSS parts is compared with that of uncoated ones. While the average surface roughness (Ra) of the uncoated samples was in the range of 0.40 μm, that of the AlTiN- and TiN-coated samples was in the range of 0.60 and 0.80 μm, respectively.

Research limitations/implications

It would be interesting to search different coatings for cutting tools. It could be the good idea for future work to concentrate on wear properties of tool materials.

Practical implications

The detailed mechanical and metallurgical results can be used to assess the AlTiN and TiN coating applications in HSS materials.

Originality/value

This paper provides information on mechanical and metallurgical behaviour of AlTiN- and TiN-coated HSS materials and offers practical help for researchers and scientists working in the coating area.

Details

Industrial Lubrication and Tribology, vol. 67 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

To view the access options for this content please click here
Article
Publication date: 2 March 2012

Monika Blattmeier, Gerd Witt, Johannes Wortberg, Jan Eggert and Jochen Toepker

The purpose of this paper is to provide macromechanical insight into the fatigue behaviour of laser sintered parts and to understand the influence of the laser sintered…

Downloads
1030

Abstract

Purpose

The purpose of this paper is to provide macromechanical insight into the fatigue behaviour of laser sintered parts and to understand the influence of the laser sintered surface structure on this behaviour.

Design/methodology/approach

A background on the technological maturity of manufacturing processes and the demand for structural and aesthetic properties of laser sintered plastic products is given. As the contribution of surface structure on part quality was the focus, laser sintered specimens with and without surface finishes, as well as injection moulded specimens were used. The latter simply served as a comparison and was not intended to qualify injection moulding. The study comprises the determination of short‐term tensile properties, the load increase method for investigating fracture and deformation behaviours, and fatigue crack propagation analysis.

Findings

According to the test results, the contribution of laser sintered surface structures to relevant mechanical properties can be neglected. Under dynamic loading conditions, laser sintered specimens achieved a longer lifetime but showed less deformation capabilities in contrast to injection moulded specimens. In general, laser sintered specimens presented considerable resistance to crack initiation and propagation.

Research limitations/implications

Because of the long‐term approach of the research, the number of tests conducted per lot was limited. Thus, the effects of different process settings and the reproducibility could not be fully analysed.

Practical implications

The studied fatigue behaviour of laser sintered specimens has implications for the functional testing of parts or components, for the product and process design as well as for the general compatibility of laser sintering as a manufacturing technology of end‐customer products.

Originality/value

The value of this paper lies in the better understanding of deformation and fracture behaviours of laser sintered polymers.

To view the access options for this content please click here
Article
Publication date: 11 March 2014

Grazielle de Oliveira Setti, Jorge Vicente Lopes da Silva, Marcelo Fernandes de Oliveira, Izaque Alves Maia, Dosil Pereira de Jesus, Raluca Savu, Thebano Emilio de Almeida Santos, Rita de Cássia Zacardi de Souza and Ednan Joanni

The purpose of this paper is to characterize polyamide parts prepared by the SLS process using techniques that are dependent on surface properties and compare the results…

Abstract

Purpose

The purpose of this paper is to characterize polyamide parts prepared by the SLS process using techniques that are dependent on surface properties and compare the results to density measurements in order to assess which technique better reflects the degree of densification achieved using different laser power levels.

Design/methodology/approach

Fabrication of Nylon 12 (Duraform PA) samples and their characterization by apparent density measurements, perfilometry, Raman spectroscopy, scanning electron microscopy, specific surface area and contact angle measurements.

Findings

Methods dependent on surface analysis are not suitable indicators of the degree of sample densification. Among the surface methods, the results from Raman spectroscopy are the ones with the best performance. Incipient sintering of the superficial layers and raw material powder on the surface, inherent to the parts made by the SLS process, strongly interfere with the characterization.

Originality/value

Quantitative comparison of a number of surface probing methods for monitoring densification of SLS parts. Characterization of sample surfaces with and without raw material powder.

Details

Rapid Prototyping Journal, vol. 20 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 1 February 2001

Joanne Yip, Kwong Chan, Kwan Moon Sin and Kai Shui Lau

The surface properties of materials are often the important determinants of their usefulness, and many of the chemical treatments now in use are aimed at modifying these…

Abstract

The surface properties of materials are often the important determinants of their usefulness, and many of the chemical treatments now in use are aimed at modifying these properties. The important properties of polymer materials such as adhesion, friction, wetting, penetrability and biological compatibility are strongly influenced by their surface characteristics. Low Temperature Plasma (LTP) is a technology which can produce not only interesting morphological modification on the surface of the polymers, but also can replace less environmental-friendly finishing processes. In this paper, four non-polymerizing plasma gases: oxygen, argon, tetrafluoromethane and 75%/25% nitrogen/hydrogen mixture were used to modify Nylon 6 filaments and fabrics. The results of SEM study reveals that interesting morphological changes on the surface of treated samples. Besides, with the appropriate LTP treatment, the fabric properties, such as the hydrophobicity of polyamides, surface luster, etc. can be greatly modified.

Details

Research Journal of Textile and Apparel, vol. 5 no. 1
Type: Research Article
ISSN: 1560-6074

Keywords

To view the access options for this content please click here
Article
Publication date: 1 August 2005

A. Tolga Bozdana

To review the most commonly used mechanical surface enhancement (MSE) techniques and their applications available in aerospace industry.

Downloads
6355

Abstract

Purpose

To review the most commonly used mechanical surface enhancement (MSE) techniques and their applications available in aerospace industry.

Design/methodology/approach

A brief description of each technique, as well as advantages and disadvantages over other techniques are given. The effects of those techniques on the surface characteristics and service properties of treated components are summarised. Finally, the applications of such techniques in the aerospace industry are presented with descriptive illustrations.

Findings

Provides a know‐how information and also comparison of techniques. Guides researchers and engineers to proper and appropriate use of each technique for relevant case or application.

Research limitations/implications

The list of techniques can be extended to a wider range which may perhaps include specific and special purpose surface enhancement methods. The applications given in the paper are mainly industrial examples of such techniques which may reduce its usefulness in academia.

Practical implications

A very useful source of information and reference for companies and engineers working in repair and production technologies of aerospace components, and also a valuable guidance for researchers and academia or for those who are intending to make a research on surface enhancement technologies.

Originality/value

This paper introduces the most commonly used MSE techniques and their effects on the service properties of aerospace components, and provides a practical help and information for people in the industry and academia.

Details

Aircraft Engineering and Aerospace Technology, vol. 77 no. 4
Type: Research Article
ISSN: 0002-2667

Keywords

To view the access options for this content please click here
Article
Publication date: 3 April 2017

József Hlinka, Miklós Berczeli, Gábor Buza and Zoltán Weltsch

This paper aims to discuss the effect of surface treatment on the wettability between copper and a lead-free solder paste. The industrial applications of laser…

Abstract

Purpose

This paper aims to discuss the effect of surface treatment on the wettability between copper and a lead-free solder paste. The industrial applications of laser technologies are increasing constantly. A specific laser treatment can modify the surface energy of copper and affect the wetting properties.

Design/methodology/approach

The surfaces of copper plates were treated using an Nd:YAG laser with varying laser powers. After laser surface treatment, wetting experiments were performed between the copper plates and SAC305 lead-free solder paste. The effect of laser treatment on copper surface was analysed using optical microscopy and scanning electron microscopy (SEM).

Findings

The experimental results showed that the wetting contact angles changed with the variation in laser power. Furthermore, it means that the surface energy of copper plates was changed by the laser treatment. The results demonstrated that the contact angles also changed when a different soldering paste was used.

Originality/value

Previous laser surface treatment can be a possible way to optimize the wettability between solders and substrates and to increase the quality of the soldered joints.

Details

Soldering & Surface Mount Technology, vol. 29 no. 2
Type: Research Article
ISSN: 0954-0911

Keywords

1 – 10 of over 24000