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Metals
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Surface Engineering of Metals and Alloys
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Surface Engineering of Metals and Alloys

A special issue of Metals (ISSN 2075-4701). This special issue belongs to the section "Corrosion and Protection".

Deadline for manuscript submissions: closed (31 January 2022) | Viewed by 58660

Special Issue Editor

Prof. Dr. Krzysztof Rokosz

E-Mail Website
Guest Editor
Department of Mechanical Engineering, Koszalin University of Technology, 75-453 Koszalin, Poland
Interests: plasma electrolytic oxidation (PEO); micro arc oxidation (MAO); electropolishing (EP); magnetoelectropolishing (MEP); biomaterials (titanium, tantalum, niobium, and their alloys); surface characterization; XPS, GDOES, SEM, EDS; corrosion studies; 2D and 3D roughness measurements
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Nowadays, the surface treatments of metals and alloys allow to obtain on them the films or coatings with different physical and chemical properties from the substrate. The most often used surface modification methods are as follows electropolishing (EP, MEP) and plasma electrolytic oxidation (PEO), also known as Micro Arc Oxidation (MAO), electrophoretic deposition (EPD) and ion implantation (IM), chemical or physical vapor deposition (CVD, PVD), anodic oxidation, carburization nitrocarburization and passivation, laser treatments, hydrothermal treatments, abrasive treatments and shot peening as well as thermoreactive deposition and sol-gel coatings.

It must be pointed out that that present Special Issue in Metals is a continuation of closed already subject Surface Treatment Technology of Metals and Alloys, in which some aspects of surface modification by selected methods were presented. That way, I would like to invite all researchers interested in widely understood surface engineering of metals and alloys to present their results in papers related to both experimental and theoretical studies.

Prof. Dr. Krzysztof Rokosz
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Metals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • surface functionalization and modification
  • electropolishing (EP, MEP) and plasma electrolytic oxidation (micro arc oxidation)
  • electrophoretic deposition (EPD) and ion implantation (IM)
  • chemical or physical vapor deposition (CVD, PVD)
  • anodic oxidation and passivation
  • laser treatments, hydrothermal treatments
  • sol-gel coatings and thermoreactive deposition
  • biomaterials and self-assembling structures
  • abrasive treatments and shot peening

Published Papers (21 papers)

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Editorial

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5 pages, 197 KiB  
Editorial
Surface Engineering of Metals and Alloys
by Krzysztof Rokosz
Metals 2022, 12(4), 542; https://doi.org/10.3390/met12040542 - 23 Mar 2022
Cited by 2 | Viewed by 1498
Abstract
Nowadays, the surface treatments of metals and alloys allow us to obtain from them the films or coatings with different physical and chemical properties from the substrate [...] Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)

Research

Jump to: Editorial, Review

11 pages, 2780 KiB  
Article
Structural Characterization of Ion Nitrided 316L Austenitic Stainless Steel: Influence of Treatment Temperature and Time
by Ozkan Gokcekaya, Celaletdin Ergun, Turgut Gulmez, Takayoshi Nakano and Safak Yilmaz
Metals 2022, 12(2), 306; https://doi.org/10.3390/met12020306 - 10 Feb 2022
Cited by 4 | Viewed by 1973
Abstract
The ion nitriding behavior of AISI 316L austenite stainless steel was investigated at different nitriding times (2 h, 4 h, and 9 h) and temperatures (450 °C, 500 °C, and 550 °C). The structural characterization has been assessed by several considerations which can [...] Read more.
The ion nitriding behavior of AISI 316L austenite stainless steel was investigated at different nitriding times (2 h, 4 h, and 9 h) and temperatures (450 °C, 500 °C, and 550 °C). The structural characterization has been assessed by several considerations which can be listed: (i) the evaluation of phase distribution through Rietveld analysis of X-ray diffraction patterns and accompanying peak fitting process, (ii) hardness profile and related nitride layer thickness by microhardness and microscopic measurements, and (iii) displacement measurements to assess the residual stress accumulation. The diffusion of nitrogen atomic species into the sample surface caused a transformation of the γ phase matrix into an expanded austenite (γN) phase, which is recognized with its high hardness and wear resistance. Furthermore, depending on the nitriding condition, chromium nitride (Cr1-2N) and iron nitride (ε-Fe2-3N and γ′-Fe4N) phases were detected, which can be detrimental to the corrosion resistance of the 316L austenite stainless steel. The γN phase was observed in all nitriding conditions, resulting in a significant increase in the surface hardness. However, decomposition of the γN phase with an increase in nitriding temperature eventually altered the surface hardness distribution in the nitriding layer. Considering the phase-type and distribution with the consequent hardness characteristics in the nitride layer, to our best knowledge, this is the first report in which an ion-nitriding temperature of 500 °C (higher than 450 °C) and time of 9 h can be proposed as ideal processing parameters leading to optimal phase composition and hardness distribution for 316L austenite stainless steels particularly for the applications requiring a combination of both wear and corrosion resistance. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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14 pages, 2377 KiB  
Article
Corrosion Behaviour and J774A.1 Macrophage Response to Hyaluronic Acid Functionalization of Electrochemically Reduced Graphene Oxide on Biomedical Grade CoCr
by Belén Chico, Blanca Teresa Pérez-Maceda, Sara San José, María Lorenza Escudero, María Cristina García-Alonso and Rosa María Lozano
Metals 2021, 11(7), 1078; https://doi.org/10.3390/met11071078 - 05 Jul 2021
Cited by 6 | Viewed by 1641
Abstract
Improvements in the lubrication of metal–metal joint prostheses are of great clinical interest in order to minimize the particles released during wear–corrosion processes. In this work, electrochemically reduced graphene oxide (ErGO) on CoCr was functionalized with hyaluronic acid (ErGOHA). Functionalization was carried out [...] Read more.
Improvements in the lubrication of metal–metal joint prostheses are of great clinical interest in order to minimize the particles released during wear–corrosion processes. In this work, electrochemically reduced graphene oxide (ErGO) on CoCr was functionalized with hyaluronic acid (ErGOHA). Functionalization was carried out by soaking for 24 h in phosphate buffer saline (PBS) solution containing 3 g/L hyaluronic acid (HA). The corrosion performance of CoCrErGO and CoCrErGOHA surfaces was studied by electrochemical impedance spectroscopy (EIS) for 7 days in PBS. Biocompatibility and cytotoxicity were studied in mouse macrophages J774A.1 cell line by the measurement of mitochondrial activity (WST-1 assay) and plasma membrane damage (LDH assay). The inflammatory response was examined through TNF-α and IL-10 cytokines in macrophages culture supernatants, used as indicators of pro-inflammatory and anti-inflammatory responses, respectively. EIS diagrams of CoCrErGOHA revealed two time constants: the first one, attributed to the hydration and diffusion processes of the HA layer adsorbed on ErGO, and the second one, the corrosion resistance of ErGOHA/CoCr interface. Macrophage assays showed better behavior on CoCrErGOHA than CoCr and CoCrErGO surfaces based on their biocompatible, cytotoxic, and inflammatory responses. Comparative analysis of IL-10 showed that functionalization with HA induces higher values of anti-inflammatory cytokine, suggesting an improvement in inflammatory behavior. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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17 pages, 7816 KiB  
Article
Improving the Corrosion Behavior of Biodegradable AM60 Alloy through Plasma Electrolytic Oxidation
by Abdulrahman I. Alateyah, Talal A. Aljohani, Majed O. Alawad, Sally Elkatatny and Waleed H. El-Garaihy
Metals 2021, 11(6), 953; https://doi.org/10.3390/met11060953 - 11 Jun 2021
Cited by 22 | Viewed by 2403
Abstract
Magnesium (Mg) alloys have unique properties. However, their applications are limited in working environments due to their poor corrosion resistance. Plasma electrolytic oxidation (PEO) is one of the most environmentally friendly and cost-effective ways that has been promoted to treat Mg alloys. In [...] Read more.
Magnesium (Mg) alloys have unique properties. However, their applications are limited in working environments due to their poor corrosion resistance. Plasma electrolytic oxidation (PEO) is one of the most environmentally friendly and cost-effective ways that has been promoted to treat Mg alloys. In this study, we investigated the effect of electrical parameters on the microstructure, as well as the mechanical and corrosion resistance of AM60 alloy coated with PEO. The electrical parameters studied were current mode (unipolar and bipolar), frequency and duty ratio. The microstructure evolution of the coated AM60 substrates was studied using X-ray diffraction and scanning electron microscopy. Subsequently, the mechanical properties were determined using compression tests and microhardness measurements. The potentiodynamic polarization curves indicated that the PEO-coated samples experienced a significant decrease of 99.9% in the corrosion rate compared to the base metal. The electrochemical impedance spectroscopy findings showed that PEO coating increased the corrosion resistance of the AM60 magnesium alloy by 1071870% compared to the base metal. On the other hand, the PEO coated samples showed superior adhesion to the substrate. Moreover, the PEO coating led to an improvement in the hardness value by 114% compared to base metal, coupled with insignificant change in the compressive properties. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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14 pages, 6276 KiB  
Article
Laser Cavitation Peening and Its Application for Improving the Fatigue Strength of Welded Parts
by Hitoshi Soyama
Metals 2021, 11(4), 531; https://doi.org/10.3390/met11040531 - 24 Mar 2021
Cited by 16 | Viewed by 2119
Abstract
During conventional submerged laser peening, the impact force induced by laser ablation is used to produce local plastic deformation pits to enhance metallic material properties, such as fatigue performance. However, a bubble, which behaves like a cavitation, is generated after laser ablation, known [...] Read more.
During conventional submerged laser peening, the impact force induced by laser ablation is used to produce local plastic deformation pits to enhance metallic material properties, such as fatigue performance. However, a bubble, which behaves like a cavitation, is generated after laser ablation, known as “laser cavitation.” On the contrary, in conventional cavitation peening, cavitation is generated by injecting a high-speed water jet into the water, and the impacts of cavitation collapses are utilized for mechanical surface treatment. In the present paper, a mechanical surface treatment mechanism using laser cavitation impact, i.e., “laser cavitation peening”, was investigated, and an improvement in fatigue strength from laser cavitation peening was demonstrated. The impact forces induced by laser ablation and laser cavitation collapse were evaluated with a polyvinylidene fluoride (PVDF) sensor and a submerged shockwave sensor, and the diameter of the laser cavitation was measured by observing a high-speed video taken with a camera. It was revealed that the impact of laser cavitation collapse was larger than that of laser ablation, and the peening effect was closely related to the volume of laser cavitation. Laser cavitation peening improved the fatigue strength of stainless-steel welds. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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18 pages, 7235 KiB  
Article
Subsurface Microstructural Evolution of High-Pressure Diecast A365: From Cast to Cold-Sprayed and Heat-Treated Conditions
by Alino Te, Bryer C. Sousa, Brajendra Mishra and Danielle L. Cote
Metals 2021, 11(3), 432; https://doi.org/10.3390/met11030432 - 05 Mar 2021
Cited by 2 | Viewed by 2239
Abstract
The use of cold spray deposition, coupled with diffusion-driven thermal postprocessing, is considered herein as a surface modification process such that near-surface microstructural, micromechanical, and microchemical property improvements can be procured for cost-effective and common aluminum alloy castings. Since the present work was [...] Read more.
The use of cold spray deposition, coupled with diffusion-driven thermal postprocessing, is considered herein as a surface modification process such that near-surface microstructural, micromechanical, and microchemical property improvements can be procured for cost-effective and common aluminum alloy castings. Since the present work was an exploratory investigation into the realm of cold spray induced, high-pressure diecast aluminum subsurface property development and evolution, as well as surface modification, one significant aim was to formalize a set of fundamental observations for continued consideration of such an approach to achieving premium aluminum alloy properties from cost-effective alternatives. Nickel, copper, and titanium cold spray modified near-surface regions of the cost-effective high-pressure diecast A365 system was considered. Near-surface, subsurface, and surface evolution was documented across each of the three pure metal coatings. The analysis was continued across two postprocessing coating-substrate atomic diffusion inspired heat-treated conditions as well. Using energy-dispersive X-ray spectroscopy, field-emission scanning electron microscopy, optical microscopy, and various insights gleaned from an original contextualization of the relevant cold spray literature, noteworthy results were recorded and discussed herein. When copper feedstock was employed alongside thermal postprocessing, diverse surface-based intermetallic compounds formed alongside exotic diffusion zones and severely oxidized regions, thus eliminating thermally activated copper cold-sprayed consolidations from future work too. However, both nickel and titanium cold spray surface modification processing demonstrated potential and promise if correct processing stages were performed directly and chronologically. Consequently, a platform is presented for further research on cold sprayed surface microstructural and property modification of cost-effective alloyed aluminum castings. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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23 pages, 13011 KiB  
Article
Finite Element Analysis of the Magnetic Field Distribution in a Magnetic Abrasive Finishing Station and its Impact on the Effects of Finishing Stainless Steel AISI 304L
by Michał Marczak and Józef Zawora
Metals 2021, 11(2), 194; https://doi.org/10.3390/met11020194 - 21 Jan 2021
Cited by 4 | Viewed by 2001
Abstract
In this article, we present a numerical model of a magnetic abrasive finishing station, which was analyzed using the finite element method (FEM). The obtained results were compared with the real values measured on an experimental station of our own design. The prepared [...] Read more.
In this article, we present a numerical model of a magnetic abrasive finishing station, which was analyzed using the finite element method (FEM). The obtained results were compared with the real values measured on an experimental station of our own design. The prepared station had the option of adjusting the magnetic flux density inside the machining gap, the width of which could be changed from 10 to 30 mm. The maximum value of the magnetic flux density inside the air gap was 0.8 T. The real distribution of magnetic flux density in the finishing area was also analyzed. A design of experiment was carried out with the following variables: abrasive grain concentration, width of the machining gap, and process duration. The results are presented in the form of regression equations and characteristics for selected roughness parameters. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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18 pages, 6434 KiB  
Article
Hydrophobic Modification of Graphene Oxide and Its Effect on the Corrosion Resistance of Silicone-Modified Epoxy Resin
by Wei Yuan, Qian Hu, Jiao Zhang, Feng Huang and Jing Liu
Metals 2021, 11(1), 89; https://doi.org/10.3390/met11010089 - 05 Jan 2021
Cited by 18 | Viewed by 3058
Abstract
This study modified graphene oxide (GO) with hydrophilic octadecylamine (ODA) via covalent bonding to improve its dispersion in silicone-modified epoxy resin (SMER) coatings. The structural and physical properties of ODA-GO were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction analysis (XRD), Fourier [...] Read more.
This study modified graphene oxide (GO) with hydrophilic octadecylamine (ODA) via covalent bonding to improve its dispersion in silicone-modified epoxy resin (SMER) coatings. The structural and physical properties of ODA-GO were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle tests. The ODA-GO composite materials were added to SMER coatings by physical mixing. FE-SEM, water absorption, and contact angle tests were used to evaluate the physical properties of the ODA-GO/SMER coatings, while salt spray, electrochemical impedance spectroscopy (EIS), and scanning Kelvin probe (SKP) methods were used to test the anticorrosive performance of ODA-GO/SMER composite coatings on Q235 steel substrates. It was found that ODA was successfully grafted onto the surfaces of GO. The resulting ODA-GO material exhibited good hydrophobicity and dispersion in SMER coatings. The anticorrosive properties of the ODA-GO/SMER coatings were significantly improved due to the increased interfacial adhesion between the nanosheets and SMER, lengthening of the corrosive solution diffusion path, and increased cathodic peeling resistance. The 1 wt.% ODA-GO/SMER coating provided the best corrosion resistance than SMER coatings with other amounts of ODA-GO (including no addition). After immersion in 3.5 wt.% NaCl solution for 28 days, the low-frequency end impedance value of the 1 wt.% ODA-GO/SMER coating remained high, at 6.2 × 108 Ω·cm2. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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21 pages, 6613 KiB  
Article
Influence of Exposure to Environment on Degradation of a Friction Stir Welded Aluminum Alloy
by Shengli Lv, Zhi Li, Xiaosheng Gao and Tirumalai S. Srivatsan
Metals 2020, 10(11), 1437; https://doi.org/10.3390/met10111437 - 29 Oct 2020
Cited by 3 | Viewed by 1641
Abstract
We carried out a comparative study on both the stress corrosion response and corrosion damage characteristics of aluminum alloy 2219, both the base material and a friction stir welding (FSW) counterpart upon exposure to exfoliation corrosion (EXCO) solution. The results reveal that the [...] Read more.
We carried out a comparative study on both the stress corrosion response and corrosion damage characteristics of aluminum alloy 2219, both the base material and a friction stir welding (FSW) counterpart upon exposure to exfoliation corrosion (EXCO) solution. The results reveal that the test specimen containing an FSW joint reveals better electrochemical corrosion resistance than that taken from the base metal. When test specimens upon exposure to EXCO solution are concurrently subjected to a tensile stress, since the mechanical properties of the FSW joint are lower than the base metal, a test specimen containing an FSW joint is more easily prone to the early initiation of fine microscopic cracks. This makes the test specimen containing the FSW joint to be less resistant to stress corrosion damage than that taken from the base metal for the various levels of applied stress and exposure time to EXCO solution. The average corrosion depth of the test specimen containing the FSW joint is less than that of the base metal, while the maximum corrosion depth of it is greater than that of the base metal. This reveals that test specimen containing the FSW joint is more susceptible to damage and degradation than test specimen taken from the base metal. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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14 pages, 6127 KiB  
Article
Influencing Microstructure of Vanadium Carbide Reinforced FeCrVC Hardfacing during Gas Metal Arc Welding
by Karsten Günther and Jean Pierre Bergmann
Metals 2020, 10(10), 1345; https://doi.org/10.3390/met10101345 - 08 Oct 2020
Cited by 14 | Viewed by 2697
Abstract
Vanadium carbide (VC) reinforced FeCrVC hardfacings have become important to improve the lifetime of tools suffering abrasive and impact loads. This is because the microstructural properties of such hardfacings enable the primary VCs to act as obstacles against the penetrating abrasive. Because dilution [...] Read more.
Vanadium carbide (VC) reinforced FeCrVC hardfacings have become important to improve the lifetime of tools suffering abrasive and impact loads. This is because the microstructural properties of such hardfacings enable the primary VCs to act as obstacles against the penetrating abrasive. Because dilution is supposed to be the key issue influencing the precipitation behaviour of primary carbides during surfacing, the development of deposit welding processes exhibiting a reduced thermal impact, and hence lower dilution to the base material, is the primary focus of the current research. By inserting an additional hot wire in the melt, an approach was developed to separate the material and energy input during gas metal arc welding (GMAW), and hence realised low dilution claddings. The carbide content could be increased, and a grain refinement was observed compared with conventional GMAW. These effects could be attributed to both the reduced dilution and heterogeneous nucleation. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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16 pages, 4761 KiB  
Article
Surface Pretreatment and Fabrication Technology of Braided Carbon Fiber Rope Aluminum Matrix Composite
by Jun Liang, Chunjing Wu, Hang Ping, Ming Wang and Weizhong Tang
Metals 2020, 10(9), 1212; https://doi.org/10.3390/met10091212 - 09 Sep 2020
Cited by 4 | Viewed by 3006
Abstract
Carbon fiber is mainly distributed in the shape of short fibers and continuous fiber bundles as the reinforcing phase in metal matrix composites, and it is seldom studied as braided rope shaped to reinforce the matrix. For this paper, the pretreatment and the [...] Read more.
Carbon fiber is mainly distributed in the shape of short fibers and continuous fiber bundles as the reinforcing phase in metal matrix composites, and it is seldom studied as braided rope shaped to reinforce the matrix. For this paper, the pretreatment and the surface metallization of the carbon fiber braided rope were studied. Besides, the casting experiments of aluminum-based carbon fiber braided rope composites were performed without external pressure. XPS analysis shows that the surface of the carbon fiber braided rope treated with ultrasonic degumming contains many hydrophilic oxygen-containing functional groups C-OH, C=O, COOH, etc., which can effectively improve the wettability between the carbon fiber braided rope and the aluminum matrix. SEM, EDS, and XRD were used to analyze the micromorphology and structure of the copper plating on the surface of carbon fiber braided ropes obtained from different pH plating solutions. When pH is 12, a continuous, uniform, and dense layer was formed on the surface of carbon fiber braided ropes. In addition, copper coating can effectively inhibit the formation of Al4C3 brittle phase. Finally, the mechanical properties results indicated that the tensile strength of the carbon fiber bundle and carbon fiber rope reinforced composite materials were 69 MPa and 83 MPa, respectively, indicating that the reinforcing effect of the carbon fiber rope is better than that of the carbon fiber bundle. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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15 pages, 4612 KiB  
Article
Characterization of Magnetoelectropolished Stainless Steel Surfaces’ Texture by Using the Angle-Resolved Scattering and Image Processing Analysis Methods
by Wojciech Kapłonek, Krzysztof Rokosz and Danil Yurievich Pimenov
Metals 2020, 10(8), 1098; https://doi.org/10.3390/met10081098 - 13 Aug 2020
Cited by 5 | Viewed by 2186
Abstract
In this article, the results of preliminary experimental studies related to a fast, non-contact assessment of the AISI 316L stainless austenitic steel surfaces after electrochemical polishing in a magnetic field have been presented. The experiments were realized with the use of a modified [...] Read more.
In this article, the results of preliminary experimental studies related to a fast, non-contact assessment of the AISI 316L stainless austenitic steel surfaces after electrochemical polishing in a magnetic field have been presented. The experiments were realized with the use of a modified angle-resolved scattering (ARS) method based on the analysis of angular distribution of the scattered light intensity. Digital images of such distribution were acquired for selected areas of examined samples—base surface and surface after magnetoelectropolishing (MEP) process. Parametric analysis oriented toward the calculation of selected key geo- and photometric parameters carried out in Image Pro®-Plus software allowed for characterization of the surface conditions of the assessed samples in terms of their scattering properties. The obtained experimental results confirmed the usefulness of the ARS method used in the presented studies as well as the possibility of its practical use (after appropriate modifications) on a wider scale, especially in industrial applications. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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13 pages, 3683 KiB  
Article
Evaluation of Surface Integrity in 18CrNiMo7-6 Steel after Multiple Abrasive Waterjet Peening Process
by Yun Zou, Yafeng Xu, Jingkai Li, Shuhao Liu, Dong Wang and Yang Li
Metals 2020, 10(6), 844; https://doi.org/10.3390/met10060844 - 26 Jun 2020
Cited by 14 | Viewed by 2562
Abstract
Abrasive waterjet peening (AWJP) as an important surface strengthening method can effectively improve surface properties. In this study, after multiple AWJP, the distribution of compressive residual stress and roughness on the surface of 18CrNiMo7-6 steel has been evaluated by an X-ray diffraction (XRD) [...] Read more.
Abrasive waterjet peening (AWJP) as an important surface strengthening method can effectively improve surface properties. In this study, after multiple AWJP, the distribution of compressive residual stress and roughness on the surface of 18CrNiMo7-6 steel has been evaluated by an X-ray diffraction (XRD) method and a 3D surface topography system, respectively. Compared with the single AWJP, multiple AWJP can obviously increase the surface residual stresses (−1024 MPa to −1455 MPa) and the depth of maximum compressive residual stress (100 μm to 120 μm), as well as make the stress distribution more uniform. In terms of the surface roughness, multiple AWJP influences its uniform distribution and reduces the surface roughness (Sa = 0.69 μm), compared with a single AWJP (Sa = 2.96 μm), due to the smaller shot balls and a uniform deformation during multiple AWJP. In addition, we have studied the effects of multiple AWJP on the hardness of the surface layer. The results show that multiple AWJP increases the hardness by up to 15.9%, compared to the single AWJP. These studies provide useful insight into improving the surface properties of 18CrNiMo7-6 steel by multiple AWJP. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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12 pages, 8342 KiB  
Article
A Mechanism for Inducing Compressive Residual Stresses on a Surface by Laser Peening without Coating
by Yuji Sano, Koichi Akita and Tomokazu Sano
Metals 2020, 10(6), 816; https://doi.org/10.3390/met10060816 - 18 Jun 2020
Cited by 27 | Viewed by 3704
Abstract
Laser peening without coating (LPwC) involves irradiating materials covered with water with intense laser pulses to induce compressive residual stress (RS) on a surface. This results in favorable effects, such as fatigue enhancement; however, the mechanism underlying formation of the compressive RS is [...] Read more.
Laser peening without coating (LPwC) involves irradiating materials covered with water with intense laser pulses to induce compressive residual stress (RS) on a surface. This results in favorable effects, such as fatigue enhancement; however, the mechanism underlying formation of the compressive RS is not fully understood. In general, tensile RS is imparted on the surface of the material due to shrinkage after heating by laser irradiation. In this study, we assessed the thermo-mechanical effect of single laser pulse irradiation and introduce a phenomenological model to predict the outcome of LPwC. To validate this model, RS distribution across the laser-irradiated spot was analyzed using X-ray diffraction with synchrotron radiation. In addition, the RS was evaluated across a line and over an area, following irradiation by multiple laser pulses with partial overlapping. Large tensile RSs were found in the spot irradiated by the single pulse; however, compressive RSs appeared around the spot. In addition, the surface RS state shifted to the compressive side due to an increase in overlap between neighboring laser pulses on the line and over the area of irradiation. The compressive RSs around a subsequent laser spot effectively compensated the tensile component on the previous spot by controlling the overlap, which may result in compressive RSs on the surface after LPwC. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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20 pages, 5415 KiB  
Article
Analytical Prediction of Residual Stress in the Machined Surface during Milling
by Caixu Yue, Xiaole Hao, Xia Ji, Xianli Liu, Steven Y. Liang, Lihui Wang and Fugang Yan
Metals 2020, 10(4), 498; https://doi.org/10.3390/met10040498 - 09 Apr 2020
Cited by 14 | Viewed by 3483
Abstract
An analytical prediction model for residual stress during milling is established, which considers the thermal-mechanical coupling effect. Considering the effects of thermal-mechanical coupling, the residual stress distribution in the workpiece is determined by the stress loading history according to McDowell′s hybrid algorithm. Based [...] Read more.
An analytical prediction model for residual stress during milling is established, which considers the thermal-mechanical coupling effect. Considering the effects of thermal-mechanical coupling, the residual stress distribution in the workpiece is determined by the stress loading history according to McDowell′s hybrid algorithm. Based on the analysis of the geometric relationship of orthogonal cutting, the prediction model for milling force and residual stress in the machined surface is established. The research results can provide theoretical basis for stress control during milling. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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13 pages, 4866 KiB  
Article
Micro-Machining Characteristics in High-Speed Magnetic Abrasive Finishing for Fine Ceramic Bar
by Joonhyuk Song, Takeo Shinmura, Sang Don Mun and Minyoung Sun
Metals 2020, 10(4), 464; https://doi.org/10.3390/met10040464 - 02 Apr 2020
Cited by 13 | Viewed by 2413
Abstract
The research aims to describe the micro-machining characteristics in a high-speed magnetic abrasive finishing, which is applicable for achieving the high surface accuracy and dimensional accuracy of fine ceramic bars that are typically characterized by strong hardness and brittle susceptibility. In this paper, [...] Read more.
The research aims to describe the micro-machining characteristics in a high-speed magnetic abrasive finishing, which is applicable for achieving the high surface accuracy and dimensional accuracy of fine ceramic bars that are typically characterized by strong hardness and brittle susceptibility. In this paper, the high-speed magnetic abrasive finishing was applied to investigate how the finishing parameters would have effects on such output parameters as surface roughness, variation of diameters, roundness, and removed weight. The results showed that, under variants of diamond abrasives sizing between (1, 3 and 9 µm), 1 µm showed comparatively good values as for surface roughness and roundness within shortest processing time. When the optimal condition was used, the surface roughness Ra and roundness (LSC) were improved to 0.01 µm and 0.14 µm, respectively. The tendency of diameter change could be categorized into two regions—stable and unstable. The finding from the study was that the performance of ultra-precision processing linear controlling was possibly achievable for the stable region of diameter change, while linearly controlling diameters in the workpiece. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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10 pages, 2102 KiB  
Article
Characterization and Corrosion Resistance Behavior of Shape Memory Stainless Steel Developed by Alternate Routes
by David Dias, Sandra Nakamatsu, Carlos Alberto Della Rovere, Jorge Otubo and Neide Aparecida Mariano
Metals 2020, 10(1), 13; https://doi.org/10.3390/met10010013 - 20 Dec 2019
Cited by 7 | Viewed by 2863
Abstract
The microstructural characterization and corrosion resistance behavior of Fe-Mn-Si-Cr-Ni alloy with shape memory effect was studied under different mechanical processing conditions and heat treatments, which were produced using conventional casting and routing methods to reduce costs and make production viable. Microstructural characterization was [...] Read more.
The microstructural characterization and corrosion resistance behavior of Fe-Mn-Si-Cr-Ni alloy with shape memory effect was studied under different mechanical processing conditions and heat treatments, which were produced using conventional casting and routing methods to reduce costs and make production viable. Microstructural characterization was performed with electron microscopy and x-ray diffraction techniques, electrochemical tests with polarization, and thermogravimetry techniques. The cast condition presented a dendritic structure and the presence of the secondary phases: ferrite-δ and Chi-X phase. The heat treatment eliminated phases, reincorporated elements in the matrix, and increased the austenitic grain. After the hot rolling process, the alloy exhibited a refined microstructure with recrystallized austenitic grains. The heat-treated condition presented better oxidation resistance than the other conditions, while the hot-rolled condition showed repassivation of the pits, raising them to higher levels. All conditions presented low corrosion resistance in environments containing chloride ions. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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17 pages, 4999 KiB  
Article
Fiber Laser Surface Melting of a NiTi Superelastic Alloy: Influence on Structural and Mechanical Properties
by David Dias, Osmar Sousa Santos, Wellington Alves, Milton Sergio Fernandes Lima and Maria Margareth da Silva
Metals 2019, 9(12), 1268; https://doi.org/10.3390/met9121268 - 27 Nov 2019
Cited by 5 | Viewed by 2816
Abstract
The surface melting of a NiTi superelastic alloy using a high-power laser Yb:Fiber was investigated. The influence of this process on the microstructural and mechanical properties was also examined. The reference material was a 3 mm nitinol strip with a homogeneous austenitic B2 [...] Read more.
The surface melting of a NiTi superelastic alloy using a high-power laser Yb:Fiber was investigated. The influence of this process on the microstructural and mechanical properties was also examined. The reference material was a 3 mm nitinol strip with a homogeneous austenitic B2 phase. For the laser surface melting process, input fluences were applied from 17.5 to 45 J/mm2. The morphology of the structure and the chemical composition of several regions were determined by optical microscopy, scanning electron microscopy, dispersive energy spectra, and X-ray diffraction techniques. The mechanical properties, such as modulus of elasticity and hardness, were determined using nanoindentation and microindentation techniques. The greatest surface finishing of the fusion zone was observed for the condition 35 J/mm2. Three well-defined regions (fusion zone (FZ), heat-affected zone (HAZ), base metal (BM)) could be observed and dimensions of grain size, width, and depth of the melted pool were directly affected by the laser fluence. The geometry of the molten pool could be controlled by the optimization of the laser parameters. High laser fluence caused preferential volatilization of nickel, dynamic precipitation of intermetallic phases, including Ti2Ni, Ni3Ti, and Ni4Ti3, as well as solubilization of TiC in the matrix, which led to grain refinement. Thus, high laser fluence is a suitable technique to enhance mechanical properties such as hardness and Young’s modulus. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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Review

Jump to: Editorial, Research

14 pages, 2324 KiB  
Review
An Introduction on the Laser Cladding Coatings on Magnesium Alloys
by Ainhoa Riquelme and Pilar Rodrigo
Metals 2021, 11(12), 1993; https://doi.org/10.3390/met11121993 - 09 Dec 2021
Cited by 10 | Viewed by 2852
Abstract
Magnesium alloys are a promising structural material to be used as a substitute for metals traditionally used in the automotive and aircraft sector. However, magnesium alloys have poor mechanical properties and corrosion resistance. These handicaps can be overcome through the application of coatings [...] Read more.
Magnesium alloys are a promising structural material to be used as a substitute for metals traditionally used in the automotive and aircraft sector. However, magnesium alloys have poor mechanical properties and corrosion resistance. These handicaps can be overcome through the application of coatings with improved properties. Laser cladding is a potential coating fabrication process. Furthermore, the low vaporization temperature of magnesium and the coating-substrate dilution problems increase the difficulty to coat magnesium substrates. The aim of this research is to analyze the state of art in magnesium laser cladding and investigate the effect of the most important fabrication parameters on the interaction of the different coating-substrate systems used on the mechanical properties and corrosion resistance. In addition, this work provides a guidance on laser cladding best practices for these alloys. Knowledge of how the different coating manufacturing parameters affect the final surface properties of magnesium alloys is essential for the implantation of these materials in applications for which they are currently limited. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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21 pages, 7177 KiB  
Review
Advantages of Electrochemical Polishing of Metals and Alloys in Ionic Liquids
by Olga Lebedeva, Dmitry Kultin, Alexandre Zakharov and Leonid Kustov
Metals 2021, 11(6), 959; https://doi.org/10.3390/met11060959 - 14 Jun 2021
Cited by 12 | Viewed by 4400
Abstract
Electropolishing of metal surfaces is a benign alternative to mechanical treatment. Ionic liquids are considered as green electrolytes for the electropolishing of metals. They demonstrate a number of advantages in comparison with acid aqueous solutions and other methods of producing smooth or mirror-like [...] Read more.
Electropolishing of metal surfaces is a benign alternative to mechanical treatment. Ionic liquids are considered as green electrolytes for the electropolishing of metals. They demonstrate a number of advantages in comparison with acid aqueous solutions and other methods of producing smooth or mirror-like surfaces that are required by diverse applications (medical instruments, special equipment, implants and prostheses, etc.). A wide window of electrochemical stability, recyclability, stability and tunability are just a few benefits provided by ionic liquids in the title application. An overview of the literature data on electropolishing of such metals as Ti, Ni, Pt, Cu, Al, U, Sn, Ag, Nb, stainless steel and other alloys in ionic liquids is presented. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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21 pages, 559 KiB  
Review
A Review: Thin Protective Coating for Wear Protection in High-Temperature Application
by Mokhtar Awang, Amirul Amin Khalili and Srinivasa Rao Pedapati
Metals 2020, 10(1), 42; https://doi.org/10.3390/met10010042 - 25 Dec 2019
Cited by 25 | Viewed by 4444
Abstract
Earning trust among high strength material industrialists for its sophistication, thin protective coating has gained its own maturity to date. As a result of active development in the industries, working tool has the capability of fabricating high strength materials with remarkable durability. For [...] Read more.
Earning trust among high strength material industrialists for its sophistication, thin protective coating has gained its own maturity to date. As a result of active development in the industries, working tool has the capability of fabricating high strength materials with remarkable durability. For example, unwanted tool wear due to thermally softening problems can be avoided. Therefore, the solution for that is protecting the tool with a thin protective coating that can be coated by various coating deposition methods. With the thin protective coating itself possessing remarkable degree of chemical and mechanical properties, the combination of both makes the thin protective coating lead to a useful extend. This paper provides a review of various research activities and various developments in the wear prone industries. Researchers have explored a number of thin protective coatings for the last century to provide a valuable guide for a most practical option. With the state of the art development of the coating methods such as electrodepositing, radio frequency ion source implantation, electron beam implantation, plasma-sprayed coating deposition, flame-sprayed coating deposition, chemical catalytic reduction deposition, vacuum-diffused deposition, vapor deposition, chemical vapor deposition, physical vapor deposition, plasma arc deposition, and some others, this paper presents the continuous development on the enhancement of the capability of the working tool chronologically since the last century. Such development was studied in connection with the ability to outlast the performance of working tool, which elevates expectations that thin protective coatings are no longer extended far beyond. Full article
(This article belongs to the Special Issue Surface Engineering of Metals and Alloys)
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