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Article
Publication date: 9 March 2015

B. S. Yilbas, Ihsan-ul-Haq Toor, Jahanzaib Malik and F. Patel

The purpose of the present study is to report the results of the laser treatment of high-strength low-alloy (HSLA) steel surface and corrosion response of the treated…

Abstract

Purpose

The purpose of the present study is to report the results of the laser treatment of high-strength low-alloy (HSLA) steel surface and corrosion response of the treated surface that was carried out. Metallurgical and morphological changes in the laser-treated layer are also examined. Laser treatment of the alloy surface improves the surface properties; however, development of high thermal stress field in the treated layer can exceed the yielding limit of the alloy lowers, particularly, the corrosion resistance of the resulting surface.

Design/methodology/approach

Pre-prepared workpiece surfaces are laser-treated and electrochemically tested in an electrolytic solution. Corrosion rate of the resulting surface is analyzed and pit sites are examined.

Findings

It is found that the presence of nitride compounds and fine grains acts like as a self-protective layer at the laser-treated surface while lowering the corrosion resistance. Consequently, laser gas-assisted treatment provides a positive effect on the corrosion properties of the treated surface through lowering the corrosion current. The pits are shallow and do not form a regular pattern at the workpiece surface. The secondary pitting is prevented by the protective layer formed at the laser-treated surface.

Research limitations/implications

The study can be extended to include laser treatment including the hard particles, such as carbides, at the surface. However, this extension is left to another study.

Practical implications

Laser treatment can be used for protection of surfaces from wear and corrosive environments. The findings of this study give insight into the improvement of the surface characteristics for this purpose. It serves to industry for the practical solution of the surface protection from corrosive environments.

Social implications

The researchers and scientists working in the area get the benefit from the outcome of this work.

Originality/value

It is an original work and gives insight into the enhancement of the corrosion resistance of HSLA steel after the laser treatment process.

Details

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

Keywords

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

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

Article
Publication date: 26 October 2012

O. Momin, S.Z. Shuja and B.S. Yilbas

A model study of laser heating process including phase change and molten flow in the melt pool gives physical insight into the process and provides useful information on…

Abstract

Purpose

A model study of laser heating process including phase change and molten flow in the melt pool gives physical insight into the process and provides useful information on the influence of melting parameters. In addition, the predictions reduce the experimental cost and minimize the experimental time. Consequently, investigation into laser control melting of the titanium alloy becomes essential. The purpose of this paper is to do this.

Design/methodology/approach

Laser repetitive pulse heating of titanium surface is investigated and temperature field as well as Marangoni flow in the melt pool is predicted using finite volume approach. The influence of laser scanning speed and laser pulse parameter (defining the laser pulse intensity distribution at the workpiece surface) on temperature distribution and melt size is examined. The experiment is carried out to validate temperature predictions for two consecutive laser pulses.

Findings

The influence of laser scanning speed is significant on the melt pool geometry, which is more pronounced for the laser pulse parameter β=0. Temperature predictions agree with the thermocouple data obtained from the experiment.

Research limitations/implications

Although temperature dependent properties are used in the simulations, isotropy in properties may limit the simulations. The laser canning speed is limited to 0.3 m/s, which is good for surface treatment process, but it may slow for annealing treatments.

Practical implications

The results are very useful to capture insight into the melting process. In addition, the influence of laser scanning speed and laser pulse intensity distribution on the melt formation in the surface vicinity is well presented, which will be useful for those working on laser surface treatment process.

Originality/value

The work is original and findings are new, which demonstrate the influence of laser parameters on the melt pool formation and resulting Marangoni flow.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 22 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 24 May 2011

Reza Shoja Razavi, Gholam Reza Gordani and H.C. Man

The purpose of this paper is to consider the corrosion properties of laser nitrided Ti‐6Al‐4V alloys that have been reported previously by several researchers.

1052

Abstract

Purpose

The purpose of this paper is to consider the corrosion properties of laser nitrided Ti‐6Al‐4V alloys that have been reported previously by several researchers.

Design/methodology/approach

Different kinds of surface nitriding methods of titanium alloys, such as plasma nitriding, ion nitriding, gas and laser nitriding, are introduced. Microstructure changes, such as phase formation and the influence of laser processing parameters in laser nitriding layers of Ti‐6Al‐4V alloys, were investigated using scanning electron microscope, transmission electron microscope, X‐ray photo‐electron spectroscopy, and X‐ray diffraction. Based on investigations presented in the literature, the effect of laser nitriding on the corrosion behavior of Ti‐6Al‐4V alloy was reviewed.

Findings

By regulating the laser processing parameter, the microstructure of the nitrided layer can be controlled to optimize corrosion properties. This layer improves corrosion behavior in most environments, due to the formation of a continuous TiNxOy passive film, which can retard the ingress of corrosive ions into the substrate and can maintain a constant value of a current density. Therefore, the laser gas nitrided specimens have a relatively noble corrosion potential and a very small corrosion current, as compared to untreated specimens.

Originality/value

This paper comprises a critical review, and its collection of references is useful. It summarizes current knowledge in laser surface treatment research.

Details

Anti-Corrosion Methods and Materials, vol. 58 no. 3
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 21 June 2011

Bekir Sami Yilbas, Cihan Karataş, Bahadır Ersu and Sevil Gurgan

The purpose of this paper is to investigate the morphological and metallurgical changes of laser gas‐assisted nitriding of titanium implants.

Abstract

Purpose

The purpose of this paper is to investigate the morphological and metallurgical changes of laser gas‐assisted nitriding of titanium implants.

Design/methodology/approach

Laser gas‐assisted nitriding of titanium implant is carried out and the metallurgical as well as the morphological changes in the nitride layer are examined using optical microscopy, SEM, XRD, and X‐ray photoelectron spectroscopy. Temperature and thermal stress fields are computed during the laser heating process adopting the finite element method. The residual stress formed in the nitride layer is measured using the XRD technique while micro‐indentation tests are carried out to determine the fracture toughness of the surface after the laser treatment process.

Findings

It is found that nitride depth layer extends to 40 μm below the surface and it is free from the cracks and micro‐voids. The residual stress formed on the surface region is higher than at some depth below the surface in the nitride layer, provided that the maximum residual stress is less than the elastic limit of the substrate material.

Originality/value

The paper contains original findings and the findings are not submitted any other journal for publication.

Details

Industrial Lubrication and Tribology, vol. 63 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 January 1994

M. Picasso and A.F.A. Hoadley

A two‐dimensional, macroscopic, stationary, finite element modelis presented for both laser remelting and laser cladding of materialsurfaces. It considers, in addition to…

Abstract

A two‐dimensional, macroscopic, stationary, finite element model is presented for both laser remelting and laser cladding of material surfaces. It considers, in addition to the heat transfer, the important fluid motion in the melt pool and the deformation of the liquid—gas interface. The velocity field in the melt is driven by thermocapillary forces for laser remelting, but also by forces due to powder injection for laser cladding. For a given velocity field within the liquid region, the stationary enthalpy (or Stefan) equation is solved. An efficient scheme allows the LU decomposition of the finite element matrix to be performed only once at the first iteration. Then, the velocity is updated using the Q1—P0 element with penalty methods for treating both the incompressibility condition and the slip boundary conditions. Numerical results for three different processing speeds for both laser remelting and laser cladding demonstrate the efficiency and robustness of the numerical approach. The influence of the thermocapillary and powder injection forces on the fluid motion and subsequently on the melt pool shape is seen to be important. This kind of calculations is thus necessary in order to predict with precision the temperature gradients across the solidification interface, which are essential data for microstructure calculations.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 4 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 9 August 2018

Milda Juciene, Virginijus Vytautas Urbelis, Žaneta Juchneviciene, Virginija Saceviciene and Vaida Dobilaite

The purpose of this paper is to determine the influence made by complex finishing of denim fabrics, i.e. laser treatment and industrial washing, on the change in tension…

Abstract

Purpose

The purpose of this paper is to determine the influence made by complex finishing of denim fabrics, i.e. laser treatment and industrial washing, on the change in tension properties of fabric.

Design/methodology/approach

Test specimens were treated by a laser JG-10050. Lasers main technological parameters: maximum laser beam power is 65 W, laser types are hermetic and detached CO2, laser tube wavelength is 10.62 µm. The test specimens processed by different laser energy density have been exposed to industrial washing and their tensile characteristics have been investigated.

Findings

The results of the research have demonstrated that complex finishing reduces the breaking force; however, material extensibility remains almost unchanged. Mechanical behaviour and composition characteristics of fabric are determined both by laser motion direction in respect of warp or weft and laser energy density.

Originality/value

The carried-out analysis of scientific literature has shown that the effect of laser on the fabric surface is relevant both in scientific and practical terms: the scientific literature contains studies on absorptive properties of laser treated materials; however, the behaviour of materials after complex finishing has not been widely investigated thus far.

Details

International Journal of Clothing Science and Technology, vol. 30 no. 4
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 8 March 2011

Uroš Trdan, Sebastjan Žagar, Janez Grum and José Luis Ocan˜a

The purpose of this paper is to investigate the effect of shock waves and strain hardening effect of laser and shot peening on precipitation‐hardened aluminium alloy AA 6082‐T651.

Abstract

Purpose

The purpose of this paper is to investigate the effect of shock waves and strain hardening effect of laser and shot peening on precipitation‐hardened aluminium alloy AA 6082‐T651.

Design/methodology/approach

The hardened layer was evaluated by means of surface integrity with optical microscopy, scanning electron microscope (SEM), energy dispersive spectroscopy, analysis of microhardness and residual stress profiles. Corrosion anodic polarization tests in a 3.5 per cent NaCl water solution were carried out to express a pitting potential and the degree of pitting attack, which was verified on SEM and with 3D metrology.

Findings

Research results indicated significant differences between two treatment techniques which had an important influence on the final condition of the surface layer. Potentiodynamic polarization tests inferred that laser peening enabled shift of the pitting potential to more positive values, which ensures higher corrosion resistance.

Originality/value

Results confirmed that the higher corrosion resistance of the laser‐peened specimens against pitting corrosion depends on the modification of the surface, due to ablation during plasma generation. Despite increased surface roughness, laser‐peened specimen exhibits beneficial increase of the pitting/breakdown potential and in reduction of pitting attack degree at the specimen surface.

Details

International Journal of Structural Integrity, vol. 2 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 13 September 2011

Kasturie Premlall, J. Herman Potgieter and S. Potgieter‐Vermaak

The effect of chlorides on corrosion of reinforcing steel is well documented in the literature. However, few studies have focused attention on the effect of sulphates on…

Abstract

Purpose

The effect of chlorides on corrosion of reinforcing steel is well documented in the literature. However, few studies have focused attention on the effect of sulphates on the corrosion of low carbon steel in alkaline media. This paper aims to address this issue.

Design/methodology/approach

This paper describes the results of the investigation into the corrosion behaviour of low carbon steel (typically used as reinforcing steel), exposed to alkaline media at a pH of 9 and 12 with varying concentrations of sulphate and chloride ions, as well as, in sulphate only solutions. An attempt was made to inhibit corrosion of steel exposed to the corrosive media using laser surface treatment of the steel specimens. Mass loss tests and electrochemical tests were conducted to evaluate the effect of sulphate only and the combined effect of sulphate and chloride ions in an alkaline media on steel.

Findings

It was found that sulphate ions could cause corrosion of steel in alkaline media. The severity of the attack increased with increasing sulphate ion concentrations, as well as with combinations of sulphate and chloride ions. The pH 12 conditions seem to show much more critical attack with evidence of pitting corrosion as compared to uniform corrosion for test conditions at a pH of 9. The attempt to inhibit the observed corrosion of steel exposed to the corrosive high alkaline media containing sulphate ions on their own and in combination of chloride ions by laser surface treatment proved to be successful.

Originality/value

The research undertaken here adds to the body of knowledge relating to the effect of sulphate ions on reinforcing steel corrosion in highly alkaline media. Most literature points out that sulphate ions on their own do not have a corrosive effect, but rather, a passivating effect!

Details

Anti-Corrosion Methods and Materials, vol. 58 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

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