Enhanced Mechanical Properties of Metals by Surface Treatments

A special issue of Coatings (ISSN 2079-6412). This special issue belongs to the section "Surface Characterization, Deposition and Modification".

Deadline for manuscript submissions: 10 November 2024 | Viewed by 13184

Special Issue Editors


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Guest Editor
College of Mechatronics & Control Engineering, Shenzhen University, Shenzhen, China
Interests: light-weight alloys; additive manufacturing; heat treatment; surface modification; lubricant coating; hardness; tribological behaviors
School of Mechanical Engineering, Hunan University of Science and Technology, Xiangtan, China
Interests: light alloy casting technology; plastic deformation technology; mechanical property; dynamic load analysis; material damage analysis
Light Alloy Research Institute, Central South University, Changsha, China
Interests: aerospace materials; ultrasonic treatment; surface strengthening; crack growth; corrosion resistance

Special Issue Information

Dear Colleagues,

Along with the swift development of high new science and technology, the necessary materials are also required to have excellent mechanical properties, wear resistance, high temperature features, or corrosion resistance, etc., particularly in the fields of aerospace, marine, and automobiles. These materials can suffer from serious wear, corrosion, or high-temperature oxidation on their surface, resulting in their initial failure and even to more serious losses. Therefore, surface characteristics of these materials should have a higher demand. By this time, a surface protection with high resistance should be provided by surface process techniques, such as laser surface treatment (LST), physical vapor deposition (PVD) and plasma electrolytic oxidation (PEO)......

We would like to invite academics and researchers to contribute to this Special Issue, entitled “Enhanced Mechanical Properties of Metals by Surface Treatments”, which is intended to serve as a unique multidisciplinary forum covering a variety of materials, advanced manufacturing technology, advanced characterization methods, performance measurements and numerical simulation.

In this Special Issue, original research articles and reviews are welcome. Research areas may include (but not limited to) the following:

  • Materials: metal alloys, ceramic materials, polymer, composites;
  • Performances: mechanical properties, wear resistance, corrosion resistance, high temperature oxidation, magnetic, biocompatibility;
  • Preparation method: laser sintering, laser melting, PVD, CVD, PEO, etc.

We look forward to receiving your contributions.

Dr. Pinghu Chen
Dr. Yun Zhang
Dr. Ruiqing Li
Guest Editors

Manuscript Submission Information

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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 modification
  • advanced materials
  • advanced treatment technology
  • advanced characterization method
  • subsequent heat treatment

Published Papers (14 papers)

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Research

14 pages, 3707 KiB  
Article
Improving the Wear Resistance Properties of 7A04 Aluminum Alloy with Three Surface Modification Coatings
by Jinmeng Hu, Cheng Zhang, Xiaodong Wang, Xiaobo Meng, Caihong Dou, Hua Yu, Changji Wang, Jun Xue, Ziping Qiao and Tao Jiang
Coatings 2024, 14(4), 476; https://doi.org/10.3390/coatings14040476 - 13 Apr 2024
Viewed by 342
Abstract
Multiple advantages, such as good formability, high specific strength, excellent thermal conductivity, and high corrosion resistance, enable aluminum alloy wide application in various fields; however, low surface hardness and poor wear resistance limit its further development. In this study, three surface modification coatings [...] Read more.
Multiple advantages, such as good formability, high specific strength, excellent thermal conductivity, and high corrosion resistance, enable aluminum alloy wide application in various fields; however, low surface hardness and poor wear resistance limit its further development. In this study, three surface modification coatings were successfully prepared on the surface of 7A04 aluminum alloy by microarc oxidation (MAO) and a combination of hard anodizing treatment (HA) and physical vapor deposition (PVD), named MAO, HA+W+DLC, and HA+Ti+ta-C, respectively. The microstructure, hardness, and tribological properties of the three coatings and the 7A04 aluminum alloy substrate were studied. The results show that the surface quality and hardness of the coated samples were higher than those of the 7A04 aluminum alloy and that the HA+Ti+ta-C coating possessed the highest hardness of 34.23 GPa. Moreover, the wear resistance of the two multilayer coatings was significantly improved during the ring-block wear tests under oil lubrication, exhibiting a wear rate of 1.51 × 10−7 mm3/N·m for HA+W+DLC and 1.36 × 10−7 mm3/N·m for HA+Ti+ta-C. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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16 pages, 11335 KiB  
Article
Axial Compression Bearing Capacity of Bolted Drum-Shaped Spherical Shell Joints: Experimental and Numerical Analysis
by Yajie Yan, Maoqing Liu, Zichun Zhou and Xingpeng Ma
Coatings 2024, 14(2), 229; https://doi.org/10.3390/coatings14020229 - 16 Feb 2024
Viewed by 673
Abstract
Bolted drum-shaped spherical shell joints (BDSSJs) represent a type of joint applicable to space grid structures. These joints merge the benefits of both bolted spherical joints and welded hollow spherical joints, embodying features such as a compact size, favorable centerline alignment with members, [...] Read more.
Bolted drum-shaped spherical shell joints (BDSSJs) represent a type of joint applicable to space grid structures. These joints merge the benefits of both bolted spherical joints and welded hollow spherical joints, embodying features such as a compact size, favorable centerline alignment with members, a high degree of adjustability, and high installation efficiency. Through unidirectional axial compression tests on specimens of BDSSJs, this study examines the stress distribution, force transmission pathways, ultimate bearing capacity, and failure modes of the joint, thereby determining its bearing capacity and presenting a bearing capacity calculation formula for such joints. By establishing a finite element model with parameters identical to the experimental specimens, this study analyzes the force and deformation of BDSSJs under unidirectional compression, identifying the high-stress areas during the compression process of BDSSJs. The findings of this study provide a basis for the practical engineering application of such joints, as well as theoretical support for subsequent dynamic performance into BDSSJs. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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11 pages, 3231 KiB  
Article
A Comparison Study on the Microstructure, Mechanical Features, and Tribological Characteristics of TiN Coatings on Ti6Al4V Using Different Deposition Techniques
by Zhen Liu, Shuai Ren, Tijun Li, Pinghu Chen, Liangbin Hu, Wenxing Wu, Sheng Li, Hao Liu, Ruiqing Li and Yun Zhang
Coatings 2024, 14(2), 156; https://doi.org/10.3390/coatings14020156 - 24 Jan 2024
Viewed by 686
Abstract
Titanium alloys are considered lightweight alloys and are widely applied across various industries. However, their low hardness, poor wear resistance, and limited oxidation resistance restrict their prospects for wider application. In this paper, nitride coatings were prepared using three preparation processes, namely laser [...] Read more.
Titanium alloys are considered lightweight alloys and are widely applied across various industries. However, their low hardness, poor wear resistance, and limited oxidation resistance restrict their prospects for wider application. In this paper, nitride coatings were prepared using three preparation processes, namely laser surface nitriding (LSN), physical vapor deposition (PVD), and plasma ion implantation (PII). Their microstructure, microhardness, tribological behavior, and high-temperature oxidation characteristics were compared. The experimental results revealed that nitrided coatings were successfully prepared using the three methods. However, a comparison of these data shows that the LSN coating exhibited superior comprehensive performance. It achieved the maximum thickness within the shortest preparation time: the thickness was about 280 μm and the deposition rate of the LSN method was 2250 and 90,000 times higher than those of the PVD and PII methods. Nitrides have high hardness, but the carrying capacity could be attributed to the thickness of the coatings: the PVD coating could withstand a force of 500 g, while the PII coating only withstood a force of less than 25 g. In addition, as hardness is the most important factor for excellent wear resistance, the average volumetric wear rate of the LSN and PVD coatings was about 9 × 10−6 mm3/m·N, and their relative wear resistance was 49.2 times that of Ti6Al4V. Meanwhile, the excellent bond between the LSN coating and the substrate was evidenced by a high-temperature oxidation test during a rapid heating–cooling cycle. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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12 pages, 4454 KiB  
Article
Influence of Initial Structural Dimensions of Plates on Welding Distortion
by Nan Guo, Hao Zhang, Xiaojie Tang, Xiqiang Ma and Xiao Wang
Coatings 2023, 13(12), 2039; https://doi.org/10.3390/coatings13122039 - 04 Dec 2023
Viewed by 751
Abstract
Aiming at the complex full-field deformation problem that easily occurs when welding plates, this paper adopts the elastic–plastic finite element method with heat-force coupling to study the deformation law of plates in different initial states. First, a rectangular plate finite element model with [...] Read more.
Aiming at the complex full-field deformation problem that easily occurs when welding plates, this paper adopts the elastic–plastic finite element method with heat-force coupling to study the deformation law of plates in different initial states. First, a rectangular plate finite element model with an initial radius and Gaussian heat source model was established to obtain the welding temperature field and deformation field of the plate; then, the method based on digital image correlation technology was used to detect the full-field dynamic deformation of the plate to verify the accuracy of the finite element model; finally, the influence of the initial structural dimensions of the plate on the weld deformation was investigated. The study shows the following: the thermoelastic–plastic finite element model proposed in this paper has high accuracy in both static and dynamic deformation; plates with the same curvature, and different lengths and widths of the initial structure of the plate welding deformation are saddle-shaped, and the edge effect of the welding of the plate is evident, independent of the length of the plate; and the maximum out-of-face deformation of the welding of the plate is linearly related to the length and the closer the aspect ratio of the plate is to 1, the smaller the out-of-face deformation is. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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14 pages, 4563 KiB  
Article
Fabrication and Characterization of Titanium Borides by Electron Beam Surface Alloying
by Fatme Padikova, Daniela Nedeva, Vladimir Dunchev, Borislav Stoyanov, Maria Ormanova, Nikolay Nedyalkov and Stefan Valkov
Coatings 2023, 13(11), 1941; https://doi.org/10.3390/coatings13111941 - 14 Nov 2023
Viewed by 767
Abstract
This study shows the possibility of the fabrication of titanium borides by an alloying of a titanium substrate with boron powder via a scanning electron beam. During the electron beam alloying experiments, the speed movement of the specimens was varied, where it was [...] Read more.
This study shows the possibility of the fabrication of titanium borides by an alloying of a titanium substrate with boron powder via a scanning electron beam. During the electron beam alloying experiments, the speed movement of the specimens was varied, where it was 4 and 6 mm/s. The thickness of the alloyed zone formed by the lower velocity of the movement of the workpiece is greater than that of the coating obtained by the higher speed movement. The phase composition of the coatings is in the form of the TiB2 phase, as well as some amount of undissolved boron in both considered cases. In the case of the lower speed of the movement of the sample, the undissolved boron is within the whole volume of the alloyed zone, while at the higher speed movement, it is on the top of the specimen. The hardness of the obtained coatings by the higher speed of the specimen movement reached values of about 4500 HV. Considering the values of the surface alloy fabricated via the lower velocity movement of 4 mm/s, it is about 2600 HV, which is lower than that of the one obtained by the 6 mm/s speed of the sample movement. The result obtained for the friction coefficient (COF) for the specimen alloyed by the speed of the specimen motion of 4 mm/s is 0.40; the value for the coating obtained at a speed movement of 6 mm/s is 0.34. In both cases, these values are lower than that of the titanium substrate. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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28 pages, 19740 KiB  
Article
The Relevance of Process Parameter Optimization and Geometric Figure for Direct Laser Deposition of Inconel 738 Alloy and Its Theoretical Modeling
by Kun Qi, Wenxing Wu, Pinghu Chen, Hao Liu and Changjun Qiu
Coatings 2023, 13(11), 1926; https://doi.org/10.3390/coatings13111926 - 10 Nov 2023
Viewed by 642
Abstract
In order to minimize the gaps between the direct laser deposition channels and improve the quality and performance of the formed parts, the process of direct laser deposition is utilized in laser additive manufacturing to create sequential, single- and double-channel deposition layers on [...] Read more.
In order to minimize the gaps between the direct laser deposition channels and improve the quality and performance of the formed parts, the process of direct laser deposition is utilized in laser additive manufacturing to create sequential, single- and double-channel deposition layers on 304 stainless steel plates. Under the premise of keeping the layer rate and defocusing amount unchanged, this study investigates the effects of laser power, scanning speed, and powder feeding rate on the morphology and inclusions of single- and double-channel deposited layers. The aim is to determine the optimal process parameter values for direct laser deposition of single-layer, single-channel Inconel 738. The effects of the three process parameters on the response values were investigated using a multi-factor, multi-level experimental design. The evaluation indexes for the analysis included the deposited layer wetting angle and aspect ratio. The analysis involved one-way extreme analysis and ANOVA analysis. The optimal process parameters are a laser power of 550~750 W, a scanning speed of 7~13 mm/s, and the powder feeding rate was 2.1~4.33 g/min. At the same time, the relationship between surface tension and gravity was integrated with the spherical coronal model and Young’s equation to develop a mathematical model of the direct laser deposition process at a theoretical level. The mathematical model of the direct laser deposition process was utilized to analyze the correlation between the geometric parameters of the cross-section of the deposited layer. This analysis provides a valuable data reference for future Inconel 738 direct laser deposition. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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12 pages, 27604 KiB  
Article
Structural Transformations on the Surface of Al-Ti Cathodes Subjected to Vacuum Arc Heating
by Gennady Pribytkov, Irina Firsina and Victoria Korzhova
Coatings 2023, 13(11), 1906; https://doi.org/10.3390/coatings13111906 - 07 Nov 2023
Viewed by 763
Abstract
AlTiN nitride coatings on the surfaces of metal-working tools can greatly extend their service life. The coatings are deposited from plasma flows generated by vacuum arc burning on the cathode surface. The elemental and charge composition of the plasma flows, as well as [...] Read more.
AlTiN nitride coatings on the surfaces of metal-working tools can greatly extend their service life. The coatings are deposited from plasma flows generated by vacuum arc burning on the cathode surface. The elemental and charge composition of the plasma flows, as well as the content of metal drops, depend on the cathode’s structure. In this paper, the microstructure, elemental, and phase compositions of the surface layer of Al-Ti cathodes subjected to vacuum arc heating were studied. These cathodes had similar elemental compositions (Ti + 50 at.% Al) but differed from one another in their phase composition and microstructure (grain size, porosity). The cathodes were studied by X-ray diffraction analysis, scanning electron microscopy, and electron probe analysis. It was found that during vacuum arc heating, surface fusion or thermal cracking of the cathode’s surface layer occurs. The thickness, structure, and phase composition of the modified layer were controlled by the thermal conductivity of the cathode material, which, in turn, depended on the phase composition and porosity of the cathodes. The maximum thickness of the modified layer (up to 400 µm) was observed on the surface of the sintered cathode due to the lower thermal conductivity of the porous structure of the cathode. The obtained results can be used for the development of coating deposition technology based on vacuum arc sputtering of multicomponent cathodes. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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10 pages, 2067 KiB  
Article
Effect of the Presence of a Silane Coupling Agent on Reaction Kinetics of Cationic Thermopolymerization of Epoxy Resin Adhesive
by Jiangcong Chen, Bingxuan Li, Shujuan Zhang and Hengfeng Li
Coatings 2023, 13(10), 1782; https://doi.org/10.3390/coatings13101782 - 17 Oct 2023
Viewed by 847
Abstract
The effect of the presence of a silane coupling agent containing different functional groups on the reaction kinetics and physical properties of epoxy resin generated via cationic thermopolymerization was investigated. The kinetics of cationic polymerization of epoxy resin was studied using a nonisothermal [...] Read more.
The effect of the presence of a silane coupling agent containing different functional groups on the reaction kinetics and physical properties of epoxy resin generated via cationic thermopolymerization was investigated. The kinetics of cationic polymerization of epoxy resin was studied using a nonisothermal DSC method. The polymerization is propagated by activated chain end (ACE) and activated monomer (AM) processes. With an increase in silane content, the ACE apparent activation energy first decreased and then increased, while the AM apparent activation energy increased. Moreover, the shear strength, coefficient of linear thermal expansion, gelation time, environmental testing of damp heat, and steady state with varied contents of silane coupling agents were evaluated. The results indicated that the presence of a silane coupling agent has more adhesion and lower water absorption than pure EP. The coefficient of linear thermal expansion and gelation time increased with the increase in silane content, while the water absorption decreased with the increase in silane content. Comparing the overall performance of three silane coupling agents used in the research, the curing system obtained by blending with vinyltrimethoxysliane (VTS) is a much better option for practical application as an adhesive. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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17 pages, 5621 KiB  
Article
Study on Cavitation Corrosion Properties of Titanium Alloy Radiation Rod with Different Roughnesses for Ultrasonic Casting
by Yilong Yang, Ya Zhang, Xuhe Liu and Haoming Zhang
Coatings 2023, 13(9), 1632; https://doi.org/10.3390/coatings13091632 - 18 Sep 2023
Cited by 1 | Viewed by 802
Abstract
To determine the mechanism of corrosion damage caused by cavitation, the properties of titanium alloy radiation rods with different roughnesses in 2A14 aluminum melt for ultrasonic casting were studied. The corrosion morphology, weight loss/cavitated area, reaction layer and microhardness of surface section were [...] Read more.
To determine the mechanism of corrosion damage caused by cavitation, the properties of titanium alloy radiation rods with different roughnesses in 2A14 aluminum melt for ultrasonic casting were studied. The corrosion morphology, weight loss/cavitated area, reaction layer and microhardness of surface section were observed, and the collapse of a single cavitation bubble was simulated. The weight loss/cavitated area caused by the physical impact of cavitation accounted for 6.4% to 8.6% of the total weight loss/cavitated area. The corrosion product was TiAl3. The reactant appeared at the Al/Ti solid–liquid interface in 4 min and the reaction layer appeared in 10 min under different roughnesses. The thickness of the work hardening layer on the surface of the material could reach 160 μm. The results show that the greater the roughness of titanium alloy in aluminum melt, the greater the rate of weight loss/cavitated area and the greater the maximum pressure in the process of cavitation bubble collapse. The evolution of the hardened layer depended on the stripping rate of the surface material caused by cavitation corrosion and the work hardening rate of the surface layer. This study provides insights to develop a new homemade Ti alloy radiation rod with better resistance to corrosion in the ultrasonic casting. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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12 pages, 2957 KiB  
Article
Experimental Study of Electrolytic Processing of Discharge-Assisted Jet Masks
by Chaoda Chen, Shaofang Wu, Tong Zhang, Yage Wang, Xiaoqiang Shao and Fengrong Mo
Coatings 2023, 13(7), 1280; https://doi.org/10.3390/coatings13071280 - 21 Jul 2023
Viewed by 855
Abstract
There has been some research on jet electrolytic processing at home and abroad, and the phenomenon of discharge during the process has been reported, but there has been little research on the mode of jet electrolysis with the aid of discharge. A jet [...] Read more.
There has been some research on jet electrolytic processing at home and abroad, and the phenomenon of discharge during the process has been reported, but there has been little research on the mode of jet electrolysis with the aid of discharge. A jet mask electrolytic processing experiment was set up to prepare a blue oil mask on the surface of the workpiece using photolithography; two processing modes were achieved using different tool electrodes, the workpiece was processed by two types of motion, the processing micro-pits were observed morphologically using an optical microscope, and the test data were analyzed by plotting graphs. Experiments show that a blue oil mask with a thickness of 50 μm covers the workpiece to strengthen the fixity, and that jet electrolytic discharge machining can effectively improve the depth-to-width ratio by increasing the contribution to depth by 30%–38% and the contribution to width by 2%–18%, compared to jet electrolytic machining. The former has less island effect than the latter, with a flatter bottom and better-machined shape. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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12 pages, 14244 KiB  
Article
Microstructure and Properties of Phosphorus Bronze/Brass Joints Produced by Resistance Projection Welding
by Ruilin Lai, Weijun Zhang, Xiaofei Sheng, Xianjue Ye, Yingfeng Cai, Xiwei Zhang, Temiao Luo, Pinghu Chen, Qian Lei and Yunping Li
Coatings 2023, 13(6), 1032; https://doi.org/10.3390/coatings13061032 - 02 Jun 2023
Cited by 1 | Viewed by 1518
Abstract
In this work, we fabricated lap joints between embossed projection phosphorus bronze and flat brass through resistance projection welding (RPW). The experimental results indicated that the bronze projection moves into the softer brass without being deformed during the welding process. The tensile shear [...] Read more.
In this work, we fabricated lap joints between embossed projection phosphorus bronze and flat brass through resistance projection welding (RPW). The experimental results indicated that the bronze projection moves into the softer brass without being deformed during the welding process. The tensile shear loads of the joint reached a maximum value of 273.6 N at a welding current of 5.5 kA. Under this circumstance, a reaction layer, including a columnar crystal solidification layer and a diffusion layer, is formed at the interface beside the boundary of bronze. The EDS line scan shows an elemental transition diffusion layer of about 1.5 μm between the H62 brass columnar crystal and XYK-6 phosphorus bronze. The fracture occurred on the XYK-6 side, passing through the bump instead of the welding interface, resulting in intactness of the welding interface. The results revealed that resistance projection welding is an effective method for welding copper alloys, suggesting the bright prospects of this technology in welding electrical parts. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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14 pages, 2978 KiB  
Article
Effect of Soil Creep on the Bearing Characteristics of Soil Slope Reinforced with CFRP and Anti-Slide Piles
by Jun Wang, Lin Liu and Ping Cao
Coatings 2023, 13(6), 1025; https://doi.org/10.3390/coatings13061025 - 01 Jun 2023
Viewed by 1012
Abstract
In order to research the displacement characteristics and stability of a soil slope reinforced with carbon-fiber-reinforced plastic (CFRP) and anti-slide piles, the displacement composition, aging deformation and failure mode of a soil mass were analyzed. According to the Mohr–Coulomb strength criterion, a new [...] Read more.
In order to research the displacement characteristics and stability of a soil slope reinforced with carbon-fiber-reinforced plastic (CFRP) and anti-slide piles, the displacement composition, aging deformation and failure mode of a soil mass were analyzed. According to the Mohr–Coulomb strength criterion, a new nonlinear, accelerated creep model of soil mass was founded with the addition of a self-building M-C plastic element. Furthermore, a viscoplastic strain analytical formula of an M-C plastic element was obtained, and the tensile deformation characteristics of a CFRP sheet were also discovered under a landslide thrust creep load. According to the environmental conditions of the anti-slide pile, the CFRP was arranged along the load-bearing side of the pile to control deformation. Combining the calculation example, it is shown that the horizontal displacement of the soil slope’s composite structure decreases by approximately 40% with CFRP reinforcement. Furthermore, for the first two calculation conditions, after one year, the maximum horizontal displacement decreased by 50% and increased by 10%, respectively. Simultaneously, the overall safety factor increased by 31.3% without soil creep properties. On the contrary, the overall safety factor was reduced, and the slope has a tendency toward unstable failure. Moreover, there is no through plastic zone in the slope. The stability of the reinforced slope and the bearing capacity of the pile are related to the CFRP method. Simultaneously, the structure can reduce the costs and construction difficulty of anti-slide piles in a complex environment surrounded by the soil creep effect. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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13 pages, 6159 KiB  
Article
Effect of Co/TiAl on Mechanical Properties of Laser Melted IN 625 on 304SS Matrix
by Tong Yang, Wenxing Wu, Yuantao Lei, Pinghu Chen, Hao Liu, Li Zhao and Changjun Qiu
Coatings 2023, 13(4), 768; https://doi.org/10.3390/coatings13040768 - 14 Apr 2023
Cited by 1 | Viewed by 1043
Abstract
IN 625 is one of the most widely used nickel-based high-temperature alloys. However, the unstable high-temperature mechanical properties of IN625 and the difficulty of processing complex parts have limited its wider application. This work fabricated IN625 coatings with Co/TiAl (1.25, 1.55, and 1.85) [...] Read more.
IN 625 is one of the most widely used nickel-based high-temperature alloys. However, the unstable high-temperature mechanical properties of IN625 and the difficulty of processing complex parts have limited its wider application. This work fabricated IN625 coatings with Co/TiAl (1.25, 1.55, and 1.85) on 304SS using laser melting deposition technology, with excellent high-temperature mechanical properties. The effects of Co/TiAl on the microstructure and properties of the laser-cladded resulting coatings have been carefully investigated. Compared to the IN625 coating, the addition of Co, Ti, and Al to the IN625 laser cladding coating significantly enhances its hardness and strength at room temperature, while reducing the elongation rate sharply. After heat treatment (900 °C × 10 h + 850 °C × 2 h), the hardness of the IN625 coating decreases, while the hardness of the IN625 laser cladding coating with added Co, Ti, and Al significantly increases. At a temperature of 850 °C, the yield strength and elongation rate of the IN625 laser cladding coating with Co, Ti, and Al additives exhibit an increasing-then-decreasing trend as the Co/TiAl ratio rises. The results exhibited that the coating had excellent high-temperature mechanical properties when the Co/TiAl is 1.55, and its hardness, tensile strength, yield strength, and elongation rate are 48.62 HRC, 735 Map, 665 MPa, and 11.3%, respectively. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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20 pages, 11791 KiB  
Article
Effect of Local Remelting and Recycled WC-Co Composite Reinforcement Size on Abrasive and Erosive Wear of Manual Arc Welded Hardfacings
by Egidijus Katinas, Maksim Antonov, Vytenis Jankauskas and Dmitri Goljandin
Coatings 2023, 13(4), 734; https://doi.org/10.3390/coatings13040734 - 04 Apr 2023
Cited by 2 | Viewed by 1417
Abstract
The hardfacings reinforced by recycled (cermet inserts of machining tools) WC-Co composite particles applied by manual arc welding can be used for protection against abrasive and erosive wear. Two categories of coatings were analyzed: with and without thermal treatment (local remelting). The hardfacings [...] Read more.
The hardfacings reinforced by recycled (cermet inserts of machining tools) WC-Co composite particles applied by manual arc welding can be used for protection against abrasive and erosive wear. Two categories of coatings were analyzed: with and without thermal treatment (local remelting). The hardfacings were tested under abrasive (low and medium stress) and erosive (high stress) conditions. In elevated temperature erosive conditions, coatings without heat treatment have up to two times higher wear resistance than reference material. Under low-stress conditions, coatings with the finest reinforcing particle size (180–355 µm) treated with local remelting demonstrated more than 10 times higher wear resistance than reference material. The optimal reinforcement size selection depends on the application conditions (low, average, or high stress). In most test conditions, the local remelting did not provide additional improvement. A scanning electron microscope was used for the characterization of wear mechanisms. The relation between mechanical properties and wear rates was found only for some conditions. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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