Effect of boronizing on the structural, mechanical and tribological properties of CoCrW dental alloy produced by selective laser melting

2019 ◽  
Vol 71 (3) ◽  
pp. 348-356
Author(s):  
Yakup Uzun ◽  
Halim Kovacı ◽  
Ali Fatih Yetim ◽  
Ayhan Çelik

PurposeThis paper aims to investigate the effects of boriding on the structural, mechanical and tribological properties of CoCrW dental alloy manufactured by the method of selective laser melting.Design/methodology/approachIn this study, CoCrW alloy samples that are used in dentistry were manufactured by the method of laser melting, and boriding treatment was made on the samples at 900°C and 1,000°C for 1, 4 and 8 h. The structural, mechanical and tribological effects of boriding on the samples were analyzed using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, microhardness and an abrasion test device.FindingsAccording to the results, the best outcomes in terms of abrasion strength and hardness were obtained in the sample that was subjected to boriding at 1,000°C for 4 h.Originality/valueThis study produced CoCrW alloys, which are fundamental biomaterials that are used in dentistry, by a different production method called selective laser melting and improved their surface characteristics by boriding.

2018 ◽  
Vol 24 (9) ◽  
pp. 1554-1562 ◽  
Author(s):  
Luo Zhang ◽  
Haihong Zhu ◽  
Jiahe Liu ◽  
Xiaoyan Zeng

Purpose The purpose of this paper is to investigate the track evolution and surface characteristics of selective laser melting Ti6Al4V. Design/methodology/approach In the present paper, Ti6Al4V single-track, multi-track and bulk sample were formed at different scanning speed by selective laser melting (SLM). Then, the surface morphology, three-dimension profile and surface roughness were evaluated. The width of the single and multi-track was measured and compared. Findings The results showed that the heat accumulation played a great role on the evolution of tracks and surface characteristics from single-track to multi-track and to bulk. The surface morphology of the subsequent tracks became more regular when the single-track was irregular at the same high scanning speed. The width of last track Wn was always larger than that of the first track W1. The Ra of the top of the bulk increased with the increase of the scanning speed, this trend was as same as the Ra of the single-track, but the trend of Ra of the side was opposite. Originality/value The effect of heat accumulation on the track evolution and surface characteristics is obtained. The results can help to derive a smooth surface with a regular and continuous track in SLM.


Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 946
Author(s):  
Ph. V. Kiryukhantsev-Korneev ◽  
A. D. Sytchenko ◽  
S. A. Vorotilo ◽  
V. V. Klechkovskaya ◽  
V. Yu. Lopatin ◽  
...  

Coatings in the Ta-Zr-Si-B-C-N system were produced by magnetron sputtering of a TaSi2-Ta3B4-(Ta,Zr)B2 ceramic target in the Ar medium and Ar-N2 and Ar-C2H4 gas mixtures. The structure and composition of coatings were studied using scanning electron microscopy, glow discharge optical emission spectroscopy, energy-dispersion spectroscopy, and X-ray diffraction. Mechanical and tribological properties of coatings were determined using nanoindentation and pin-on-disk tests using 100Cr6 and Al2O3 balls. The oxidation resistance of coatings was evaluated by microscopy and X-ray diffraction after annealing in air at temperatures up to 1200 °C. The reactively-deposited coatings containing from 30% to 40% nitrogen or carbon have the highest hardness up to 29 GPa and elastic recovery up to 78%. Additionally, coatings with a high carbon content demonstrated a low coefficient of friction of 0.2 and no visible signs of wear when tested against 100Cr6 ball. All coatings except for the non-reactive ones can resist oxidation up to a temperature of 1200 °C thanks to the formation of a protective film based on Ta2O5 and SiO2 on their surface. Coatings deposited in Ar-N2 and Ar-C2H4 demonstrated superior resistance to thermal cycling in conditions 20-T−20 °C (where T = 200–1000 °C). The present article compares the structure and properties of reactive and “standard-inert atmosphere” deposited coatings to develop recommendations for optimizing the composition.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ruben B.O. Acevedo ◽  
Klaudia Kantarowska ◽  
Edson Costa Santos ◽  
Marcio C. Fredel

Purpose This paper aims to generate a review of available techniques to measure Residual Stress (RS) in Ti6Al4V components made by Ti6Al4V. Design/methodology/approach State of the art; literature review in the field of Residual Stress measurement of Ti6Al4V parts made by selective laser melting (SLM). Findings Different Residual Stress measurement techniques were detailed, regarding its concept, advantages and limitations. Regarding all researched references, hole drilling (semi destructive) and X-ray diffraction (nondestructive) were the most cited techniques for Residual Stress measurement of Ti6Al4V parts made by SLM. Originality/value An extensive analysis of RS measurement techniques for Ti6Al4V parts made by SLM.


2019 ◽  
Vol 40 ◽  
pp. 249
Author(s):  
Max Amorim Brum ◽  
Fábio Beck ◽  
Oreci Escobar da Silva ◽  
Gustavo Luiz Callegari ◽  
Marcos André Carara ◽  
...  

The search for materials with well-defined characteristics is very important for any engineering project. In addition, it is known that the various types of manufacturing processes directly influence in properties of the parts. In this work, the X-ray diffraction technique was used to study the structural characteristics of Ti-6Al-4V samples manufactured by the forging and Selective Laser Melting techniques. We found that the samples made by FSL were able to present a reduction of 1% in the lattice parameter perpendicular to the studied plane, when compared with the forged samples. Since most of the parts manufactured by Selective Laser Melting meet the demands of aeronautical and aerospace projects, where residual stresses are generally undesirable for making the parts more fragile, studies like these acquire great relevance.


2020 ◽  
Vol 34 ◽  
pp. 101194 ◽  
Author(s):  
Samy Hocine ◽  
Steven Van Petegem ◽  
Ulrich Frommherz ◽  
Gemma Tinti ◽  
Nicola Casati ◽  
...  

2018 ◽  
Vol 24 (3) ◽  
pp. 670-676 ◽  
Author(s):  
Urska Kostevsek ◽  
Tomaz Brajlih ◽  
Joze Balic ◽  
Žiga Kadivnik ◽  
Igor Drstvensek

Purpose Fixed structures in prosthetic dentistry are highly customized products, manufactured individually for patients who have missing teeth. When choosing the technology for fixed dental structure manufacturing, three viable options are available (precise casting, milling and selective laser melting [SLM]). All these technologies can be used to produce a dental structure from CoCr alloy. Besides materials and availability of technologies, economic efficiency is an important factor when choosing a production method. The purpose of this study is to develop an estimation model for achievable productivity of selective laser melting and compare the results with the productivity of conventional manufacturing. Design/methodology/approach Results presented in this paper are based on manufacturing time analysis of an individual case with each of the technologies mentioned above. Because of the efficiency of SLM is highly dependent on how efficiently the work space of the machine is used, this issue was also included in the research. Data used for research were acquired from practical use of each technology in dental applications. Findings Analysis of achievable SLM manufacturing speeds is based on the previous research into manufacturing speeds of additive manufacturing technologies. The presented results present a model that can be used to estimate the productivity of the SLM technology. Research limitations/implications Research was limited to a specific SLM machine type with a fixed workspace volume. Nevertheless, the results show that any SLM machine has to be used as efficiently as possible to be able to be competitive regarding the conventional manufacturing technologies. Practical implications The presented results show clearly at least a rough estimation of what kind of parts and in what volume will be manufactured with an SLM machine prior to buying one. Social implications Results can help to widen the economically efficient way of running SLM machines, replacing conventional manufacturing for medical applications especially with complicated cases. Originality/value A method is presented to adapt the estimation model to a particular real-life production scenario. This method can be used to establish how efficiently selective laser sintering can be used and if using SLM machine instead of conventional manufacturing would be economically viable.


Author(s):  
Kyriaki Polychronopoulou ◽  
Claus Rebholz ◽  
Nicholaos G. Demas ◽  
Andreas A. Polycarpou ◽  
Lefki Theodorou ◽  
...  

This study describes the correlation between the microstructure, mechanical and tribological properties of Ti1−xCx coatings (with x being in the range of 0–0.5), deposited by reactive magnetron sputtering from a Ti target in Ar/C2H2 mixtures at ∼200 °C. The mechanical and tribological properties were found to strongly depend on the chemical composition and the microstructure present. Very dense structures and highest hardness and elastic modulus, combined with low wear rates, were observed for films with chemical composition close to TiC. X-ray diffraction (XRD) studies showed that the coating deposited at high C2H2 flow rates composed of randomly oriented TiC crystallites. Morphological investigations by scanning electron microscopy (SEM) indicate that the morphology is strongly dependent on the carbon content of the coating. Coatings composition and bonding environment was investigated using X-ray photoelectron spectroscopy (XPS). Both the mechanical properties and tribological performance of the coatings were found to be dependent on carbon content.


Sign in / Sign up

Export Citation Format

Share Document