Advances in Laser Materials Processing

A special issue of Metals (ISSN 2075-4701). This special issue belongs to the section "Additive Manufacturing".

Deadline for manuscript submissions: closed (31 December 2021) | Viewed by 37147

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Department of High-Efficiency Machining Technologies, Moscow State University of Technology STANKIN, 127055 Moscow, Russia
Interests: processing by concentrated energy flows; laser processing; electrophysical machining; heat and hardening treatment; surface finishing and coating; powder metallurgy; nanomaterials; nanocoatings and thin films; thermal spray technologies; process diagnostics and monitoring
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Guest Editor
Department of High-Efficiency Processing Technologies, Moscow State University of Technology STANKIN, Moscow, Russia
Interests: additive manufacturing; coatings; cutting ceramics; electro-physical processing; high-energy fluxes; laser processing; nanocomposites; plasma processing; sintering; thin films
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Department of High-Efficiency Processing Technologies, Moscow State University of Technology STANKIN, Moscow, Russia
Interests: additive manufacturing; electrical discharge machining; high-energy fluxes; laser processing; monitoring; thermal and chemical processes
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Laser processing becomes more relevant today due to its fast adaptation to the most critical technological tasks, ability to provide processing in the most rarefied and aggressive mediums (vacuum conditions), wide field of potential applications, and green aspects related to the absence of industrial cutting chips and dust. With the development of 3D technologies of production, laser processing has received a new round of interest associated with its ability of pointed high-precision powder melting or sintering. New technologies and equipment, which improve and modify laser optic parameters, contribute to better absorption of laser energy by metals or powder surface and allow an increase of laser power up to a few kilowatts. That can positively influence the industrial spread of the laser in mass production and advance the existing manufacturing methods.

The latest achievements in laser processing have become a relevant topic in the most authoritative scientific journals and conferences for the last half-century. Advances in laser processing have received multiple awards in the most prestigious competitions and exhibitions worldwide and at international scientific events.

The Special Issue is devoted to the most recent achievements in the field of laser processing of metals and innovative manufacturing methods based on laser.

Prof. Dr. Sergey N. Grigoriev
Dr. Marina A. Volosova
Dr. Anna A. Okunkova
Guest Editors

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Keywords

  • Laser processing
  • Additive manufacturing based on laser
  • Laser cladding
  • SLM/SLS
  • Laser ablation
  • Laser polishing
  • Laser micromachining
  • Pulsed laser
  • Coatings

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Published Papers (12 papers)

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Editorial

Jump to: Research, Review

6 pages, 226 KiB  
Editorial
Advances in Laser Materials Processing
by Sergey N. Grigoriev, Marina A. Volosova and Anna A. Okunkova
Metals 2022, 12(6), 917; https://doi.org/10.3390/met12060917 - 27 May 2022
Cited by 5 | Viewed by 2053
Abstract
Today, laser processing is becoming more and more relevant due to its fast adaptation to the most critical technological tasks, its ability to provide processing in the most rarefied and aggressive mediums (e [...] Full article
(This article belongs to the Special Issue Advances in Laser Materials Processing)

Research

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20 pages, 8601 KiB  
Article
Beam Shaping in Laser Powder Bed Fusion: Péclet Number and Dynamic Simulation
by Sergey N. Grigoriev, Andrey V. Gusarov, Alexander S. Metel, Tatiana V. Tarasova, Marina A. Volosova, Anna A. Okunkova and Andrey S. Gusev
Metals 2022, 12(5), 722; https://doi.org/10.3390/met12050722 - 24 Apr 2022
Cited by 22 | Viewed by 3872
Abstract
A uniform distribution of power density (energy flux) in a stationary laser beam leads to a decrease in the overheating of the material in the center of the laser beam spot during laser powder bed fusion and a decrease in material losses due [...] Read more.
A uniform distribution of power density (energy flux) in a stationary laser beam leads to a decrease in the overheating of the material in the center of the laser beam spot during laser powder bed fusion and a decrease in material losses due to its thermal ablation and chemical decomposition. The profile of the uniform cylindrical (flat-top) distribution of the laser beam power density was compared to the classical Gaussian mode (TEM00) and inverse Gaussian (donut) distribution (airy distribution of the first harmonic, TEM01* = TEM01 + TEM10). Calculation of the Péclet number, which is a similarity criterion characterizing the relationship between convective and molecular processes of heat transfer (convection to diffusion) in a material flow in the liquid phase, shows that the cylindrical (flat-top) distribution (TEM01* + TEM00 mode) is effective in a narrow temperature range. TEM00 shows the most effective result for a wide range of temperatures, and TEM01* is an intermediate in which evaporation losses decrease by more than 2.5 times, and it increases the absolute laser bandwidth when the relative bandwidth decreases by 24%. Full article
(This article belongs to the Special Issue Advances in Laser Materials Processing)
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11 pages, 3489 KiB  
Article
The Effect of Silica Sand Proportion in Laser Scabbling Process on Cement Mortar
by Tam-Van Huynh, Youngjin Seo and Dongkyoung Lee
Metals 2021, 11(12), 1914; https://doi.org/10.3390/met11121914 - 27 Nov 2021
Cited by 7 | Viewed by 2734
Abstract
Cement mortar composite has a wide range of applications on construction sites, including masonry, plastering and concrete repair. In construction sites, scabbling process is a method to remove from a few millimeters to several centimeters of defect concrete surfaces. As a result, it [...] Read more.
Cement mortar composite has a wide range of applications on construction sites, including masonry, plastering and concrete repair. In construction sites, scabbling process is a method to remove from a few millimeters to several centimeters of defect concrete surfaces. As a result, it is essential to investigate the scabbling characteristics for cement mortar with different silica sand proportion in laser scabbling process. In this study, 5 types of cement mortar with different silica sand proportions in mixing were fabricated and scabbled by using a high-density power laser beam. The effects of silica sand proportion in color changing and penetration depth of the samples after laser scabbling process were studied. Furthermore, the generation of micro-cracks and pores were observed by using scanning electron microscopy (SEM). In addition, chemical composition changes between processed zone and non-processed zone were also evaluated by Energy Dispersive X-ray (EDX) analysis. The results of this study are expected to provide valuable knowledge in understanding of the laser scabbling process for cement-based materials. Full article
(This article belongs to the Special Issue Advances in Laser Materials Processing)
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24 pages, 19759 KiB  
Article
Laser Micro Polishing of Tool Steel 1.2379 (AISI D2): Influence of Intensity Distribution, Laser Beam Size, and Fluence on Surface Roughness and Area Rate
by André Temmler, Magdalena Cortina, Ingo Ross, Moritz E. Küpper and Silja-Katharina Rittinghaus
Metals 2021, 11(9), 1445; https://doi.org/10.3390/met11091445 - 13 Sep 2021
Cited by 9 | Viewed by 3188
Abstract
Within the scope of this study, basic research was carried out on laser micro polishing of the tool steel 1.2379 (AISI D2) using a square, top-hat shaped intensity distribution. The influence of three different quadratic laser beam sizes (100 µm, 200 µm, 400 [...] Read more.
Within the scope of this study, basic research was carried out on laser micro polishing of the tool steel 1.2379 (AISI D2) using a square, top-hat shaped intensity distribution. The influence of three different quadratic laser beam sizes (100 µm, 200 µm, 400 µm side length) and fluences up to 12 J/cm2 on the resulting surface topography and roughness were investigated. Surface topography was analyzed by microscopy, white light interferometry, spectral roughness analysis, and 1D fast Fourier transformation. Scanning electron microscopy and electrical discharge analyses indicate that chromium carbides are the source of undesired surface features such as craters and dimples, which were generated inherently to the remelting process. Particularly for high laser fluences, a noticeable stripe structure was observed, which is typically a characteristic of a continuous remelting process. Although the micro-roughness was significantly reduced, often, the macro-roughness was increased. The results show that smaller laser polishing fluences are required for larger laser beam dimensions. Additionally, the same or even a lower surface roughness and less undesired surface features were created for larger laser beam dimensions. This shows a potential path for industrial applications of laser micro polishing, where area rates of up to several m2/min might be achievable with commercially available laser beam sources. Full article
(This article belongs to the Special Issue Advances in Laser Materials Processing)
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21 pages, 15125 KiB  
Article
Analysis of the Process Parameters, Post-Weld Heat Treatment and Peening Effects on Microstructure and Mechanical Performance of Ti–Al Dissimilar Laser Weldings
by Paola Leo, Sonia D’Ostuni, Riccardo Nobile, Claudio Mele, Andrea Tarantino and Giuseppe Casalino
Metals 2021, 11(8), 1257; https://doi.org/10.3390/met11081257 - 9 Aug 2021
Cited by 15 | Viewed by 2308
Abstract
Dissimilar Ti–Al laser weldings are very interesting due to their difficulties in being processed because of the different physical properties of the alloys and the crack formations during cooling and solidification. In this study, the effect of laser offset and defocusing on microstructure, [...] Read more.
Dissimilar Ti–Al laser weldings are very interesting due to their difficulties in being processed because of the different physical properties of the alloys and the crack formations during cooling and solidification. In this study, the effect of laser offset and defocusing on microstructure, geometry and mechanical properties response of 2 mm thick dissimilar AA6061/Ti-6Al-4V laser welds was analyzed. Moreover, in order to reduce residual stresses, the joints were both heat-treated and mechanically treated by ultrasonic peening. The welds microstructure was found to be martensitic in the Ti-6Al-4V fusion zone, columnar dendritic in the AA6061 fusion zone and partially martensitic in the Ti-6Al-4V heat-affected zone. Intermetallic compounds based on the Al–Ti system were detected at the AA6061/Ti-6Al-4V interface and in the aluminum fusion zone. Both negative defocusing and higher laser offset improved the tensile performance of the welds, mainly by reducing the amount of brittle intermetallic compounds. The stress relaxation heat treatment, leading to the aging of the martensite and the increasing of the size of the intermetallic compound, reduced the tensile strength and ductility of the joints. On the contrary, for dissimilar Al–Ti welds, mechanical treatment was effective in increasing joints ductility and, moreover, corrosion resistance. Full article
(This article belongs to the Special Issue Advances in Laser Materials Processing)
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27 pages, 8759 KiB  
Article
Effect of Cavitation Erosion Wear, Vibration Tumbling, and Heat Treatment on Additively Manufactured Surface Quality and Properties
by Sergey N. Grigoriev, Alexander S. Metel, Tatiana V. Tarasova, Anastasia A. Filatova, Sergey K. Sundukov, Marina A. Volosova, Anna A. Okunkova, Yury A. Melnik and Pavel A. Podrabinnik
Metals 2020, 10(11), 1540; https://doi.org/10.3390/met10111540 - 19 Nov 2020
Cited by 17 | Viewed by 3749
Abstract
The paper is devoted to researching various post-processing methods that affect surface quality, physical properties, and mechanical properties of laser additively manufactured steel parts. The samples made of two types of anticorrosion steels—20kH13 (DIN 1.4021, X20Cr13, AISI 420) and 12kH18N9T (DIN 1.4541, X10CrNiTi18-10, [...] Read more.
The paper is devoted to researching various post-processing methods that affect surface quality, physical properties, and mechanical properties of laser additively manufactured steel parts. The samples made of two types of anticorrosion steels—20kH13 (DIN 1.4021, X20Cr13, AISI 420) and 12kH18N9T (DIN 1.4541, X10CrNiTi18-10, AISI 321) steels—of martensitic and austenitic class were subjected to cavitation abrasive finishing and vibration tumbling. The roughness parameter Ra was reduced by 4.2 times for the 20kH13 (X20Cr13) sample by cavitation-abrasive finishing when the roughness parameter Ra for 12kH18N9T (X10CrNiTi18-10) sample was reduced by 2.8 times by vibratory tumbling. The factors of cavitation-abrasive finishing were quantitatively evaluated and mathematically supported. The samples after low tempering at 240 °C in air, at 680 °C in oil, and annealing at 760 °C in air were compared with cast samples after quenching at 1030 °C and tempering at 240 °C in air, 680 °C in oil. It was shown that the strength characteristics increased by ~15% for 20kH13 (X20Cr13) steel and ~20% for 12kH18N9T (X10CrNiTi18-10) steel than for traditionally heat-treated cast samples. The wear resistance of 20kH13 (X20Cr13) steel during abrasive wear correlated with measured hardness and decreased with an increase in tempering temperatures. Full article
(This article belongs to the Special Issue Advances in Laser Materials Processing)
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12 pages, 8042 KiB  
Article
Influence of Specific Energy on Microstructure and Properties of Laser Cladded FeCoCrNi High Entropy Alloy
by Leilei Wang, Zhuanni Gao, Mengyao Wu, Fei Weng, Ting Liu and Xiaohong Zhan
Metals 2020, 10(11), 1464; https://doi.org/10.3390/met10111464 - 2 Nov 2020
Cited by 19 | Viewed by 2879
Abstract
Specific energy is a key process parameter during laser cladding of high entropy alloy (HEA); however, the effect of specific energy on the microstructure, hardness, and wear resistance of HEA coating has not been completely understood in the literature. This paper aims at [...] Read more.
Specific energy is a key process parameter during laser cladding of high entropy alloy (HEA); however, the effect of specific energy on the microstructure, hardness, and wear resistance of HEA coating has not been completely understood in the literature. This paper aims at revealing the influence of specific energy on the microstructure and properties of laser cladded FeCoCrNi high entropy alloy on the Ti6Al4V substrate, and further obtains feasible process parameters for preparation of HEA coating. Results indicate that there are significant differences in the microstructure and properties of the coatings under different specific energy. The increase of specific energy plays a positive role in coarsening the microstructure, promoting the diffusion of Ti from the substrate to HEA coating, and subsequently affects the hardness of samples. The HEA coating is mainly composed of the face-centered cubic phase and body-centered cubic phase, precipitating a small amount of Fe-Cr phase and Laves phase. Metallurgical bonding is obtained between the base metal and the coatings of which the bonding region is mainly composed of columnar crystal and shrinkage cavities. The microhardness of the HEA coating reaches 1098 HV, which is about 200% higher than that of the TC4 substrate, and the wear resistance is significantly improved by the HEA coating. Full article
(This article belongs to the Special Issue Advances in Laser Materials Processing)
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18 pages, 8170 KiB  
Article
Effects of Laser Melting Distribution on Wear Resistance and Fatigue Resistance of Gray Cast Iron
by Haiyang Yang, Ti Zhou, Qingnian Wang and Hong Zhou
Metals 2020, 10(9), 1257; https://doi.org/10.3390/met10091257 - 17 Sep 2020
Cited by 9 | Viewed by 2554
Abstract
The coupling bionic surface is generally prepared by laser melting on the surface of a gray iron brake hub, which can allow the brake hub to achieve excellent wear resistance and fatigue resistance. The designs of most previous experiments have been based on [...] Read more.
The coupling bionic surface is generally prepared by laser melting on the surface of a gray iron brake hub, which can allow the brake hub to achieve excellent wear resistance and fatigue resistance. The designs of most previous experiments have been based on independent units that were uniform in their distribution patterns. Although some progress has been made in the optimization of cell features, there is still room for further improvement with respect to bionics and experimental optimization methods. Here, experiments on units with non-uniform distributions of different distances were used to rearrange and combine the bionic elements. This paper is that the original uniform distribution laser melting strengthening model was designed as a non-uniform distribution model, and the heat preservation and tempering strengthening effect of continuous multiple melting strengthening on the microstructure of the melting zone is discussed. The mechanism of crack initiation and the mode of crack propagation were analyzed. The relationship between the internal stress in the melting zone and the crack initiation resistance was also discussed. In this paper, the mechanism of different spacing distribution on the surface of gray cast iron by laser remelting is put forward innovatively and verified by experiments, which provides a solid theoretical basis for the follow-up industrial application. Full article
(This article belongs to the Special Issue Advances in Laser Materials Processing)
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15 pages, 8110 KiB  
Article
Bionic Repair of Thermal Fatigue Cracks in Ductile Iron by Laser Melting with Different Laser Parameters
by Siyuan Ma, Ti Zhou, Hong Zhou, Geng Chang, Benfeng Zhi and Siyang Wang
Metals 2020, 10(1), 101; https://doi.org/10.3390/met10010101 - 9 Jan 2020
Cited by 18 | Viewed by 3471
Abstract
Nodular iron brake discs typically fail due to serious thermal fatigue cracking, and the presence of graphite complicates the repair of crack defects in ductile iron. This study presents a novel method for remanufacturing ductile iron brake discs based on coupled bionics to [...] Read more.
Nodular iron brake discs typically fail due to serious thermal fatigue cracking, and the presence of graphite complicates the repair of crack defects in ductile iron. This study presents a novel method for remanufacturing ductile iron brake discs based on coupled bionics to repair thermal fatigue cracks discontinuously using bio-inspired crack blocking units fabricated by laser remelting at various laser energy inputs. Then, the ultimate tensile force and thermal fatigue crack resistance of the obtained units were tested. The microhardness, microstructure, and phases of the units were characterized using a digital microhardness meter, optical microscopy, scanning electron microscopy, and X-ray diffraction. It was found that the units without defects positively impacted both the thermal fatigue resistance and tensile strength. The unit fabricated at a laser energy of 165.6 15 + 19 J/ mm 2 had sufficient depth to fully close the crack, and exhibited superior anti-cracking and tensile properties. When the unit distance is 3 mm, the sample has excellent thermal fatigue resistance. In addition, the anti-crack mechanism of the units was analysed. Full article
(This article belongs to the Special Issue Advances in Laser Materials Processing)
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15 pages, 9182 KiB  
Article
Effect of Composition on the Mechanical Properties and Wear Resistance of Low and Medium Carbon Steels with a Biomimetic Non-Smooth Surface Processed by Laser Remelting
by Geng Chang, Ti Zhou, Hong Zhou, Peng Zhang, Siyuan Ma, Benfeng Zhi and Siyang Wang
Metals 2020, 10(1), 37; https://doi.org/10.3390/met10010037 - 24 Dec 2019
Cited by 7 | Viewed by 2692
Abstract
To study the effect of laser biomimetic treatment on different material compositions, five kinds of steels with different carbon element contents were studied by laser remelting. The characteristics (depth, width), microstructure, hardness, tensile properties, and wear resistance of the samples were compared. The [...] Read more.
To study the effect of laser biomimetic treatment on different material compositions, five kinds of steels with different carbon element contents were studied by laser remelting. The characteristics (depth, width), microstructure, hardness, tensile properties, and wear resistance of the samples were compared. The results show that when the laser processing parameters are fixed, the characteristics of the unit increase with an increase of carbon element content. Moreover, the hardness of the unit also increases. Compared with the untreated samples, when the carbon content is 0.15–0.45%, the tensile strength of the laser biomimetic samples is higher than that of the untreated samples. For the biomimetic samples with different carbon content, with an increase of carbon content, the tensile strength increases first and then decreases, while the plasticity of the biomimetic samples decreases continuously. The bionic samples have better wear resistance than that of the untreated samples. For bionic specimens with different carbon elements, wear resistance increases with an increase of carbon element content. Full article
(This article belongs to the Special Issue Advances in Laser Materials Processing)
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Review

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24 pages, 2530 KiB  
Review
On Defect Minimization Caused by Oxide Phase Formation in Laser Powder Bed Fusion
by Anna A. Okunkova, Semen R. Shekhtman, Alexander S. Metel, Nadegda A. Suhova, Sergey V. Fedorov, Marina A. Volosova and Sergey N. Grigoriev
Metals 2022, 12(5), 760; https://doi.org/10.3390/met12050760 - 28 Apr 2022
Cited by 5 | Viewed by 2742
Abstract
The article is devoted to the compressive review of the defects observed in the products of the machinery usage made mainly of anti-corrosion steels of the martensite-austenite group, difficult to process materials such as pure titanium, nickel, and their alloys, super and high [...] Read more.
The article is devoted to the compressive review of the defects observed in the products of the machinery usage made mainly of anti-corrosion steels of the martensite-austenite group, difficult to process materials such as pure titanium, nickel, and their alloys, super and high entropy alloys and triple fusions produced by laser additive manufacturing, particularly the laser powder bed fusion. Studies were conducted on the structural defects observed in such products to improve their quality in the context of residual stress elimination, porosity reduction, and surface roughness improvement. Electrophysical and electrochemical treatment methods of removing oxide phase formation during melting and remelting of deposed tracks in layers are considered (such as ultrasound, plasma, laser, spark treatment, induction cleaning, redox annealing, gas–flame, plasma–beam, plasma–spark treatment). Types of pollution (physical and chemical) and cleaning methods, particularly plasma-based methods for oxide phase removing, are classified. A compressive comparison of low- and high-pressure plasma sources is provided. Special attention is focused on the atmospheric plasma sources based on a dielectric barrier and other discharges as a part of a production setup that presents the critical value of the conducted review in the context of the novelty for transition to the sixth technology paradigm associated with the Kondratieff’s waves. Full article
(This article belongs to the Special Issue Advances in Laser Materials Processing)
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28 pages, 6821 KiB  
Review
Surface Laser Treatment of Cast Irons: A Review
by Néstor Catalán, Esteban Ramos-Moore, Adrian Boccardo and Diego Celentano
Metals 2022, 12(4), 562; https://doi.org/10.3390/met12040562 - 26 Mar 2022
Cited by 13 | Viewed by 3164
Abstract
Heat treatments are frequently used to modify the microstructure and mechanical properties of materials according to the requirements of their applications. Laser surface treatment (LST) has become a relevant technique due to the high control of the parameters and localization involved in surface [...] Read more.
Heat treatments are frequently used to modify the microstructure and mechanical properties of materials according to the requirements of their applications. Laser surface treatment (LST) has become a relevant technique due to the high control of the parameters and localization involved in surface modification. It allows for the rapid transformation of the microstructure near the surface, resulting in minimal distortion of the workpiece bulk. LST encompasses, in turn, laser surface melting and laser surface hardening techniques. Many of the works devoted to studying the effects of LST in cast iron are diverse and spread in several scientific communities. This work aims to review the main experimental aspects involved in the LST treatment of four cast-iron groups: gray (lamellar) cast iron, pearlitic ductile (nodular) iron, austempered ductile iron, and ferritic ductile iron. The effects of key experimental parameters, such as laser power, scanning velocity, and interaction time, on the microstructure, composition, hardness, and wear are presented, discussed, and overviewed. Finally, we highlight the main scientific and technological challenges regarding LST applied to cast irons. Full article
(This article belongs to the Special Issue Advances in Laser Materials Processing)
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