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1 – 10 of 247
Article
Publication date: 3 August 2021

Jie Chen, Yongqiang Yang, Shibiao Wu, Mingkang Zhang, Shuzhen Mai, Changhui Song and Di Wang

In this paper, the mechanical properties and corrosion resistance of CoCr alloy fabricated by selective laser melting (SLM) were studied, and the changes of performance after…

Abstract

Purpose

In this paper, the mechanical properties and corrosion resistance of CoCr alloy fabricated by selective laser melting (SLM) were studied, and the changes of performance after porcelain sintering process were also analysed. This study is to point out the relationship between the microstructure, mechanical properties and corrosion resistance of CoCr alloys prepared by SLM after porcelain sintering process. In addition, the biosafety of the sintered CoCr alloy was evaluated.

Design/methodology/approach

The microscopic feature changes of CoCr alloy samples after porcelain sintering process were observed by DMI 5000 M inverted metallographic microscope and Nova Nano430 FE-SEM. Moreover, phase identification and determination were conducted by X-ray diffraction (XRD) using Smartlab X-ray diffractometer. The Vickers microhardness was measured on the HVS-30 microhardness tester, and tensile tests were carried out on a CM3505 electronic universal testing machine. The corrosion resistance was tested by a classical three-point electrode system electrochemical method, then the ion precipitation was measured by using an atomic absorption spectrometer of Z2000 7JQ8024.

Findings

The XRD results indicate that the transition of γ phase (FCC) to e phase (HCP) occurs during the porcelain sintering processing of CoCr alloy. Moreover, the Vickers microhardness of the upper surface and the side surface of the CoCr alloy sample was improved by more than 36%. In addition, the ultimate strength of CoCr alloy via porcelain sintering treatment was increase to 1,395.3 ± 53.0 MPa compared to 1,282.7 ± 10.1 MPa of unprocessed CoCr alloy. However, the corrosion resistance of CoCr alloy samples decreases after porcelain sintering process.

Originality/value

There are few studies on the relationship of microstructure, mechanical properties and corrosion resistance of CoCr alloys prepared by SLM after porcelain sintering process. In this study, the microstructure, mechanical properties and corrosion resistance of CoCr alloy after porcelain sintering process were studied, and the biosafety of the alloy was evaluated. The research found that it is feasible to apply CoCr alloy fabricated by SLM to dental medicine after porcelain sintering process.

Details

Rapid Prototyping Journal, vol. 27 no. 8
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 31 December 2019

Bassam Abdallah, M. Kakhia and W. Alsadat

TiN and TiAlVN films have been prepared by DC magnetron sputtering technique at room temperature. TiN target has been used to deposit TiN thin film under pure argon (100 percent…

Abstract

Purpose

TiN and TiAlVN films have been prepared by DC magnetron sputtering technique at room temperature. TiN target has been used to deposit TiN thin film under pure argon (100 percent Ar) gas. Additionally, Ti6Al4V alloy target has been used to deposit TiAlVN under nitrogen and argon gas (50 percent Ar and 50 percent N2). In this paper, two substrate types have been used: stainless steel 304 and Si(100). This analysis has confirmed that the nitride films, (TiN/Si) and TiAlVN in both cases, have been produced. Energy Depressive X-ray Spectroscopy (EDX) measurement confirmed that the TiN/Si was stoichiometry, where the N/Ti ratio was about 1 with low oxygen contamination. The results obtained have indicated that the TiAlVN has more resistance to corrosion than TiN film in 3.5 percent NaCl at 25°C (seawater). Both films, TiAlVN/SS304 and TiN/SS304, have shown improved corrosion resistance compared with virgin 304 substrate. Microhardness was carried out using Vickers method; the microhardness values for TiN/SS304 and TiAlVN/SS304 were approximately 7.5 GPa and 25.3 GPa, respectively. The paper aims to discuss these issues.

Design/methodology/approach

The films were prepared by a DC magnetron sputtering system starting from high pure (99.99 percent) Ti6Al4V target (Al 6wt%, V 4wt% and balance Ti) in plasma discharge argon/nitrogen (50 percent Ar and 50 percent N2) for deposition of TiAlVN film. Pure TiN target (99.99 percent) was used for preparation of TiN film in pure argon plasma. The diameter of target was 50 mm and the power applied for preparation of the two films was 100 W. A cylindrical high-vacuum chamber (Figure 2) made of stainless steel 316, with height 363 mm diameter, was fabricated locally. Scanning electron microscope images have been used to discover the films morphology. The composition of the films has been determined by EDX technique for films deposited on Si substrate. The electrochemical corrosion test was carried out using conventional three-electrode cell of 300 ml capacity by using Voltalab PGZ 301 system (France) using Tafel extrapolation method and electrochemical impedance spectroscopy techniques.

Findings

TiN and TiAlVN films have been prepared by DC magnetron sputtering technique without heating of the substrates holder. The effects of the composition of nitride films on mechanical and corrosion properties were investigated. The composition of the films has been determined by EDX technique. The effect of using titanium alloy (Ti with Al and V) on the composition and crystalline quality has been investigated. The microhardness is strongly dependent on the addition of the Al and V elements, and it consequently improves mechanical proprieties. The microhardness values for TiN/SS304 were approximately 7.5 GPa and 25.3 GPa for TiAlVN/SS304. They indicate that prepared films prevent the aggressive action of corrosion media.

Originality/value

TiN and TiAlVN films have been prepared by DC magnetron sputtering method at room temperature. Titanium nitride film, especially TiAlVN, is an effective method to improve the corrosion resistance of SS304. TiAlVN film has exhibited enhanced corrosion resistance and higher microhardness. Independent time-of-flight elastic recoil detection analysis has been used to determine the composition of the film.

Details

International Journal of Structural Integrity, vol. 11 no. 6
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 25 February 2014

Ghodsieh Mashouf, Morteza Ebrahimi and Saeed Bastani

The purpose of this work was to perform a systematic study on the effect of formulation on the physical and mechanical properties of ultaviolet (UV) curable urethane acrylate…

Abstract

Purpose

The purpose of this work was to perform a systematic study on the effect of formulation on the physical and mechanical properties of ultaviolet (UV) curable urethane acrylate resins. In addition, the authors wanted to derive mathematical formula for the prediction of physical and mechanical properties for the aforementioned system.

Design/methodology/approach

The experiments were carried out based on mixture experimental design to determine the effect of different multifunctional acrylates (i.e. 1,6-hexanediol diacrylate (HDDA), tripropylene glycol diacrylate (TPGDA), trimethyolpropane triactylate (TMPTA)) concentration on the physical and mechanical properties of a UV curable polyurethane acrylate system. The urethane oligomer was synthesized and characterized by the research team. Microhardness, adhesion strength and scratch resistance of the cured films were evaluated as the physical and mechanical properties.

Findings

The results revealed that the resin and TMPTA concentrations had the most significant effects on the microhardness property. Adhesion strength of the films showed a linear trend with respect to all variables. Moreover, all components also had a significant and complex influence on the scratch resistance of the cured systems. In addition, mathematical equations proposed by mixture experimental design were derived for all the mentioned properties.

Research limitations/implications

Other multifunctional acrylate monomers (i.e. more than three functional) can be used in the formulations. The kinetics of the curing can affect on the network formation and consequently on the properties of the cured films.

Practical implications

The obtained results can be used by the researchers who are active in the field of structure-property relationship of polymers and surface coatings. The reported data and the mathematical equations can also be used for the formulating of an appropriate formulation based on a specific application.

Originality/value

A systematic and statistical-based approach, i.e. mixture experimental design, was used to evaluate the effect of formulation on some of the properties of a UV curable polyurethane acrylate system. A urethane oligomer and three different multifunctional acrylate monomers as reactive diluents were used in the formulations. Noteworthy to mention that several mathematical models were derived by using analysis of variance for the prediction of the properties studied in this system.

Details

Pigment & Resin Technology, vol. 43 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 2 August 2021

Peipei Lu, Meiping Wu, Xin Liu, Xiaojin Miao and Weipeng Duan

Ti6Al4V is a widely used metal for biomedical application due to its excellent corrosion resistance, biocompatibility and mechanical strength. However, a coupling reaction of…

Abstract

Purpose

Ti6Al4V is a widely used metal for biomedical application due to its excellent corrosion resistance, biocompatibility and mechanical strength. However, a coupling reaction of friction and corrosion is the critical reason for the failure of implants during the long-term service in human body, shortening the life expectancy and clinical efficacy of prosthesis. Hence, this study aims to find a feasible approach to modify the service performances of Ti6Al4V.

Design/methodology/approach

Selective laser melting (SLM), as one of the emerging metal-based additive manufacturing (AM) technologies is capable for fabricating patient-specific personalized customization of artificial prosthesis joints, owing to its high adaptability for complex structures. This study is concerned with the tribocorrosion behavior of SLM fabricated Ti6Al4V substrate enhanced by laser rescanning and graphene oxide (GO) mixing. The tribocorrosion tests were performed on a ball-on-plate configuration under the medium of simulated body fluid (SBF). Moreover, the surface morphologies, microstructures, microhardness and contact angle tests were used to further reveal the in-situ strengthening mechanism of GO/Ti6Al4V nanocomposites.

Findings

The results suggest that the strengthening method of GO mixing and laser rescanning shows its capability to enhance the wear resistance of Ti6Al4V by improving surface morphologies and promoting the generation of hard phases. The wear volume of R-GO/Ti6Al4V is 5.1 × 10−2 mm3, which is 25.0% lower than that of pure SLM-produced Ti6Al4V. Moreover, a wear-accelerated corrosion of the Ti6Al4V occurs in SBF medium, leading to a drop in the open circuit potential (OCP), but R-GO/Ti6Al4V has the lowest tendency to corrosion. Compared to that of pure Ti6Al4V, the microhardness and contact angle of R-GO/Ti6Al4V were increased by 32.89% and 32.60%, respectively.

Originality/value

Previous investigations related to SLM of Ti6Al4V have focused on improving its density, friction and mechanical performances by process optimization or mixing reinforcement phase. The authors innovatively found that the combination of laser rescanning and GO mixing can synergistically enhance the tribocorrosion properties of titanium alloy, which is a feasible way to prolong the service lives of medical implants.

Details

Rapid Prototyping Journal, vol. 28 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 19 May 2012

Mohammad Ismail, Bala Muhammad, Esah Hamzah and TanWui Keong

The purpose of this paper is to present results of an evaluation of dual‐phase and galvanized steel reinforcements in corrosive environments.

Abstract

Purpose

The purpose of this paper is to present results of an evaluation of dual‐phase and galvanized steel reinforcements in corrosive environments.

Design/methodology/approach

Low carbon steels were intercritically annealed at 740°C followed by water quenching to obtain dual‐phase structures with 37 per cent volume fraction of martensite dispersed in ferrite matrix. Dual‐phase and galvanized steel rebars were embedded in concrete cubes and immersed in 5 per cent NaCl solution for up to 100 days. Corrosion rate, tensile and macro as well as microhardness tests were performed. The dual‐phase and galvanized zinc layers were observed under scanning electron microscopy (SEM).

Findings

From all of the tests carried out it was found that dual‐phase steels exhibited better corrosion resistant properties and superior strength compared to galvanized steels.

Originality/value

The results reported show that dual‐phase steel can be a good candidate for reinforcement in concrete especially in aggressive and corrosive environments.

Details

Anti-Corrosion Methods and Materials, vol. 59 no. 3
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 9 November 2010

Antonyraj Arockiasamy, Dan Eliezer, Paul T. Wang, M.F. Horstemeyer and Roger L. King

The aim of this paper is to investigate the effect of cathodic charging and corrosion behavior of Ti‐48Al‐2Cr‐2Nb alloy in hydrochloric acid solutions.

Abstract

Purpose

The aim of this paper is to investigate the effect of cathodic charging and corrosion behavior of Ti‐48Al‐2Cr‐2Nb alloy in hydrochloric acid solutions.

Design/methodology/approach

TiAl alloy specimens of thickness 0.5 mm were cathodically charged in 0.1 M HCl solution at room temperature. The prominent current densities selected for this investigation were 25 and 50 mA cm−2 for durations of 24‐120 h. The change in weight of the specimen after charging was measured by a microbalance with an accuracy of ±1 μg.

Findings

The nature of the specimen surfaces was characterized by X‐ray diffraction (XRD), auger electron spectroscopy (AES) and scanning electron microscopy (SEM) equipped with energy dispersive X‐ray spectroscopy (EDS). XRD revealed the phase transformation from microcrystalline to nano‐crystalline, particularly after high charging times (120 h) and high current density (50 mA cm−2). AES and EDS further assessed the compositional fluctuations on both cathodically charged and potentiodynamically polarized specimens. Surface corrosion leading to the generation of microcracks throughout the surface region was observed by SEM. Cathodic charging and the polarization process were responsible for embrittlement and pitting. Decreases in both weight and Vickers hardness values with an increase in charging time revealed that surface erosion depended strongly upon charging density.

Originality/value

The results presented in this work shed light on the role of alloying elements the passive behavior and their implications on their stability in hydrochloric acid environments.

Details

Anti-Corrosion Methods and Materials, vol. 57 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 29 May 2009

Luca Facchini, Emanuele Magalini, Pierfrancesco Robotti and Alberto Molinari

The purpose of this paper is the microstructural and mechanical characterization of a biomedical Ti‐6Al‐4V alloy produced by electron beam melting, and the study of the stability…

5899

Abstract

Purpose

The purpose of this paper is the microstructural and mechanical characterization of a biomedical Ti‐6Al‐4V alloy produced by electron beam melting, and the study of the stability of the as‐built microstructure upon heat treatment.

Design/methodology/approach

Ti‐6Al‐4V alloy produced by electron beam melting has been mechanically characterized through tensile and fatigue testing. Its microstructure has been investigated by optical observation after etching and by X‐ray diffractometry analysis. The stability of the microstructure of the as‐built material has been deepened carrying out suitable heat treatments, after an analysis by dilatometry test.

Findings

The microstructure of a Ti‐6Al‐4V alloy produced by electron beam melting has a very fine and acicular morphology, because of the intrinsically high‐solidification rate of the process. This microstructure is very stable, and the traditional thermal treatments cannot modify it; the microstructure changes significantly only when an amount of strain is introduced in the material. However, the mechanical properties of the alloy produced by electron beam melting are good.

Originality/value

The paper provides evidence of the microstructural stability of the material produced by electron beam melting. Even if the microstructure of the as‐built material is not recommended by the specific ISO standard, the related mechanical properties are fully satisfactory. This is a significant indication from the point of view of the production of Ti‐6Al‐4V orthopaedic and dental prostheses by electron beam melting.

Details

Rapid Prototyping Journal, vol. 15 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 8 August 2020

Qiqiang Cao, Jiong Zhang, Shuai Chang, Jerry Ying Hsi Fuh and Hao Wang

This study aims to further the understanding of support structures and the likely impacts on maraging steel MS1 parts fabricated by selective laser melting (SLM) at 45°, 60° and…

Abstract

Purpose

This study aims to further the understanding of support structures and the likely impacts on maraging steel MS1 parts fabricated by selective laser melting (SLM) at 45°, 60° and 75° building angles.

Design/methodology/approach

Two groups of samples, one group with support structures and the other group without support structures, were designed with the same specifications and printed under the same conditions by SLM at 45°, 60° and 75° building angles. Differences in dimensional accuracy, surface roughness, Vickers microhardness, residual stress and microstructure were compared between groups.

Findings

The results showed that with support structures, more accurate dimension and slightly higher Vickers microhardness could be obtained. Larger compressive stress dominated and was more uniformly distributed on the supporting surface. Without support structures, the dimension became more precise as the building angle increased and alternating compressive and tensile stress was unevenly distributed on the supporting surface. In addition, the surface roughness of the outer surface decreased with the increase of the built angle, regardless of the support structures. Furthermore, whether the building angle was 45°, 60° or 75°, the observed microstructures revealed that the support structures altered the orientation of the molten pool and the direction of grain growth.

Originality/value

This paper studies the influence of support structures on the workpieces printed at different building angles. Support structures affect the residual stress distribution, heat dissipation rate and microstructure of the parts, and thus affecting the printing quality. Therefore, it is necessary to balance the support strategy and printing quality to better apply or design the support structures in SLM.

Details

Rapid Prototyping Journal, vol. 26 no. 9
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 7 June 2022

Fredrik Bjørheim, Dimitrios Pavlou and Sudath C. Siriwardane

Brinell, Vickers and low-force Vickers hardness measurements are herein adopted to investigate and quantify the fatigue damage evolution in specimens made of S355J2+AR ferritic…

Abstract

Purpose

Brinell, Vickers and low-force Vickers hardness measurements are herein adopted to investigate and quantify the fatigue damage evolution in specimens made of S355J2+AR ferritic pearlitic steel. Though nano and microhardness measurements have been well adopted, they require a strict preparation routine, whereas macroscopic hardness measurements are not as stringent.

Design/methodology/approach

The feasibility of adopting macroscopic hardness measurements as a means of measuring fatigue damage is investigated through a combination of experimental tests and finite element analyses with both Brinell and Vickers hardness indenter.

Findings

It is found that the Brinell hardness measurements method seems more feasible, regarding finding a continuous and significant change during the fatigue life, in comparison to both Vickers and low-force Vickers. Thereafter, the question regarding the feasibility of the hardness measurements as a method of assessing accumulated fatigue damage in situ is discussed.

Originality/value

Much work has previously been performed towards correlation of the micro and nano hardness indentations, which generally has stringent preparation requirements before testing. Herein, the adoption of macroscopic hardness measurements as a means of assessing accumulated fatigue damage is considered both experimentally and theoretically.

Details

International Journal of Structural Integrity, vol. 13 no. 4
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 1 March 2013

Elias P. Koumoulos, Costas A. Charitidis, Nikolaos M. Daniolos and Dimitrios I. Pantelis

The purpose of this paper is to determine if the nanoindentation technique is a reliable method and whether it can be used to measure the surface hardness (H) in friction stir…

Abstract

Purpose

The purpose of this paper is to determine if the nanoindentation technique is a reliable method and whether it can be used to measure the surface hardness (H) in friction stir welded aluminum alloys. In order to test the reliability of nanoindentation technique, nanohardness values for friction stir welded aluminum alloys were compared to microhardness values. Additionally, the onset of plasticity (yielding) is investigated.

Design/methodology/approach

Nanoindentation experiments were performed for the determination of onset on plasticity (yielding) and comparison of local mechanical properties of both welded alloys. In order to test the reliability of nanoindentation technique, nanohardness values for friction stir welded AA6082 were compared to microhardness values. The specimen was tested using two different instruments – a Vickers microhardness tester and a nanoindenter tester for fine scale evaluation of H.

Findings

The results of this study indicate that nanohardness values with a Berkovich indenter reliably correlate with Vickers microhardness values. Nanoindentation technique can provide reliable results for analyzing friction stir welded aluminum alloys. The welding process definitely affects the material mechanical properties.

Originality/value

Microhardness and nanohardness obtained values can be correlated carefully, regarding the similarities and the differences of the two above mentioned techniques.

Details

International Journal of Structural Integrity, vol. 4 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

1 – 10 of 247