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Titanium Alloys and Titanium-Based Matrix Composites
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Titanium Alloys and Titanium-Based Matrix Composites

A special issue of Metals (ISSN 2075-4701).

Deadline for manuscript submissions: closed (30 June 2021) | Viewed by 61147

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editor

Prof. Dr. Maciej Motyka

E-Mail Website1 Website2
Guest Editor
Department of Materials Science, Rzeszow University of Technology, Rzeszow, Poland
Interests: titanium alloys; hot deformation; superplasticity; ultrafine-grained materials; superalloys; directional solidification
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Titanium alloys, thanks to unique physical and chemical properties (mainly high relative strength combined with very good corrosion resistance), are considered as advanced metallic materials. Their development has led to design of several groups of structural alloys, including single-phase: α or β alloys, two-phase α + β alloys—the most popular ones—and TiAl intermetallic alloys. The main application areas of titanium alloys include transportation (mainly aerospace structures), machine building, fuel-energetic industry and medicine. The application of conventional titanium alloys is limited due to their high chemical affinity to atmospheric gases (single α phase alloys can be used up to 600 °C). However, Ti-based intermetallic alloys seems to be promising alternative materials for high temperature use. Obviously, it needs to overcome some technological problems—like low ductility—which have been partially resolved over the last decades. Another important feature of titanium is its remarkable biocompatibility. Especially low Young’s modulus titanium alloys are considered nowadays as valuable biomaterials used for bone implants (including “gum metals”). Titanium alloys are also good materials for metal matrix composites (MMC’s). Their main attractions are high strength and stiffness—dependently on the type of reinforcement.

The range of material applications are also related to modern manufacturing and processing technologies. In case of titanium and its alloys, interesting results were obtained by grain refinement, which causes high strength increase. Pure nanocrystalline titanium is characterized be the strength level very close to solution-strengthened titanium alloys. Moreover, ultrafine-grained titanium alloys exhibit high superplastic deformability. Another developing processing areas worth mentioning are: surface engineering, joining methods (e.g. diffusion bonding or friction stir welding—FSW) and highly promising additive manufacturing (AM) method.

The purpose of this Special Issue is to collect works related to various aspects of research on titanium alloys and Ti-based matrix composites—manufacturing and processing methods and materials characterization. It is my pleasure to invite you to submit manuscripts for this Special Issue. Full papers, communications, and reviews are all welcome.

Prof. Dr. Maciej Motyka
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

  • Titanium alloys
  • Titanium-based intermetallic alloys
  • Titanium-based matrix composites
  • Microstructure development and characterization
  • Mechanical behavior
  • Applications
  • Manufacturing
  • Processing
  • Additive manufacturing
  • Surface engineering

Published Papers (21 papers)

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Editorial

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4 pages, 200 KiB  
Editorial
Titanium Alloys and Titanium-Based Matrix Composites
by Maciej Motyka
Metals 2021, 11(9), 1463; https://doi.org/10.3390/met11091463 - 15 Sep 2021
Cited by 9 | Viewed by 2283
Abstract
Titanium alloys have been considered unique materials for many years [...] Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)

Research

Jump to: Editorial, Review, Other

9 pages, 5582 KiB  
Article
Effect of Pre-Strain on Microstructure and Tensile Properties of Ti-6Al-4V at Elevated Temperature
by Taowen Wu, Ning Wang, Minghe Chen, Dunwen Zuo, Lansheng Xie and Wenxiang Shi
Metals 2021, 11(8), 1321; https://doi.org/10.3390/met11081321 - 20 Aug 2021
Cited by 6 | Viewed by 2148
Abstract
Research on pre-deformation influences on material properties in multistep hot forming is of important scientific interest. In this paper, hot tensile tests at 850 °C and a strain rate of 0.001 s−1 were performed to study the microstructural evolution and mechanical properties [...] Read more.
Research on pre-deformation influences on material properties in multistep hot forming is of important scientific interest. In this paper, hot tensile tests at 850 °C and a strain rate of 0.001 s−1 were performed to study the microstructural evolution and mechanical properties of Ti-6Al-4V with pre-strains at 0.05, 0.1 and 0.15. The tensile test results showed that the specimen with 0.05 pre-strain exhibited higher flow stress and larger elongation. Additionally, increasing the pre-strain resulted in a decrease in ultimate tensile strength (UTS) and elongation (EL). The EBSD results showed that the main deformation mechanism of Ti-6Al-4V was high-angle grain boundary sliding. Pre-strain promoted dynamic recrystallization (DRX) by increasing the deformation substructure. The refinement of grains and the eradication of dislocations enhanced the deformability, resulting in an increase in flow stress. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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16 pages, 8078 KiB  
Article
An Experimental Study of the Tension-Compression Asymmetry of Extruded Ti-6.5Al-2Zr-1Mo-1V under Quasi-Static Conditions at High Temperature
by Chen Zhang, Dongsheng Li, Xiaoqiang Li and Yong Li
Metals 2021, 11(8), 1299; https://doi.org/10.3390/met11081299 - 17 Aug 2021
Cited by 5 | Viewed by 1993
Abstract
The tension-compression asymmetry (TCA) behavior of an extruded titanium alloy at high temperatures has been investigated experimentally in this study. Uniaxial tensile and compressive tests were conducted from 923 to 1023 K with various strain rates under quasi-static conditions. The corresponding yield stress [...] Read more.
The tension-compression asymmetry (TCA) behavior of an extruded titanium alloy at high temperatures has been investigated experimentally in this study. Uniaxial tensile and compressive tests were conducted from 923 to 1023 K with various strain rates under quasi-static conditions. The corresponding yield stress and asymmetric strain hardening behavior were obtained and analyzed. In addition, the microstructure at different temperatures and stress states indicates that the extruded TA15 profile exhibits a significant yield stress asymmetry at different testing temperatures. The flow stress and yield stress during tension are greater than compression. The yield stress asymmetry decreases with the increase in temperature. The alloy also exhibits TCA behavior on the strain hardening rate. Its mechanical response during compression is more sensitive than tension. A dynamic recrystallization phenomenon is observed instead of twin generated in tension and compression under high-temperature quasi-static conditions. The grains are elongated along the tensile direction and deformed by about 45° along the compressive load axis. Finally, the TCA of Ti-6.5Al-2Zr-1Mo-1V (TA15) alloy is due to slip displacement. The tensile deformation activates basal <a>, prismatic <a> and pyramidal <c + a> slip modes, while the compressive deformation activates only prismatic <a> and pyramidal <c + a> slip modes. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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11 pages, 10319 KiB  
Article
Phase Transformations upon Ageing in Ti15Mo Alloy Subjected to Two Different Deformation Methods
by Kristína Bartha, Josef Stráský, Anna Veverková, Jozef Veselý, Jakub Čížek, Jaroslav Málek, Veronika Polyakova, Irina Semenova and Miloš Janeček
Metals 2021, 11(8), 1230; https://doi.org/10.3390/met11081230 - 02 Aug 2021
Cited by 5 | Viewed by 1654
Abstract
Ti15Mo alloy was subjected to two techniques of intensive plastic deformation, namely high pressure torsion and rotary swaging at room temperature. The imposed strain resulted in the formation of an ultrafine-grained structure in both deformed conditions. Detailed inspection of the microstructure revealed the [...] Read more.
Ti15Mo alloy was subjected to two techniques of intensive plastic deformation, namely high pressure torsion and rotary swaging at room temperature. The imposed strain resulted in the formation of an ultrafine-grained structure in both deformed conditions. Detailed inspection of the microstructure revealed the presence of grains with a size of around 100 nm in both conditions. The microstructure after rotary swaging also contained elongated grains with a length up to 1 µm. Isothermal ageing at 400 °C and 500 °C up to 16 h was applied to both conditions to investigate the kinetics of precipitation of the α phase and the recovery of lattice defects. Positron annihilation spectroscopy indicated that the recovery of lattice defects in the β matrix had already occurred at 400 °C and, in terms of positron trapping, was partly compensated by the precipitation of incoherent α particles. At 500 °C the recovery was fully offset by the formation of incoherent α/β interfaces. Contrary to common coarse-grained material, in which the α phase precipitates in the form of lamellae, precipitation of small and equiaxed α particles occurred in the deformed condition. A refined two-phase equiaxed microstructure with α particles and β grain sizes below 1 μm is achievable by simple rotary swaging followed by ageing. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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8 pages, 2981 KiB  
Article
Evolution of the Microstructure and Mechanical Properties of a Ti35Nb2Sn Alloy Post-Processed by Hot Isostatic Pressing for Biomedical Applications
by Joan Lario, Ángel Vicente and Vicente Amigó
Metals 2021, 11(7), 1027; https://doi.org/10.3390/met11071027 - 25 Jun 2021
Cited by 10 | Viewed by 1802
Abstract
The HIP post-processing step is required for developing next generation of advanced powder metallurgy titanium alloys for orthopedic and dental applications. The influence of the hot isostatic pressing (HIP) post-processing step on structural and phase changes, porosity healing, and mechanical strength in a [...] Read more.
The HIP post-processing step is required for developing next generation of advanced powder metallurgy titanium alloys for orthopedic and dental applications. The influence of the hot isostatic pressing (HIP) post-processing step on structural and phase changes, porosity healing, and mechanical strength in a powder metallurgy Ti35Nb2Sn alloy was studied. Powders were pressed at room temperature at 750 MPa, and then sintered at 1350 °C in a vacuum for 3 h. The standard HIP process at 1200 °C and 150 MPa for 3 h was performed to study its effect on a Ti35Nb2Sn powder metallurgy alloy. The influence of the HIP process and cold rate on the density, microstructure, quantity of interstitial elements, mechanical strength, and Young’s modulus was investigated. HIP post-processing for 2 h at 1200 °C and 150 MPa led to greater porosity reduction and a marked retention of the β phase at room temperature. The slow cooling rate during the HIP process affected phase stability, with a large amount of α”-phase precipitate, which decreased the titanium alloy’s yield strength. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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11 pages, 4520 KiB  
Article
Precipitation Behavior of ω Phase and ω→α Transformation in Near β Ti-5Al-5Mo-5V-1Cr-1Fe Alloy during Aging Process
by Yi Guo, Shaohong Wei, Sheng Yang, Yubin Ke, Xiaoyong Zhang and Kechao Zhou
Metals 2021, 11(2), 273; https://doi.org/10.3390/met11020273 - 05 Feb 2021
Cited by 11 | Viewed by 1945
Abstract
In this work, the precipitation behavior of the ω phase and ω→α transformation in Ti-5Al-5Mo-5V-1Cr-1Fe (Ti-55511) alloy was investigated during isothermal aging at 450 °C. The results show that the α precipitates increase with the increasing of aging time, resulting from the β→α [...] Read more.
In this work, the precipitation behavior of the ω phase and ω→α transformation in Ti-5Al-5Mo-5V-1Cr-1Fe (Ti-55511) alloy was investigated during isothermal aging at 450 °C. The results show that the α precipitates increase with the increasing of aging time, resulting from the β→α and ω→α transformations. The ω→→α transformation involves the formation and evolution of the isothermal ω phase. The formation of the isothermal ω phase occurs after 30 min and ends at 120 min, which is caused by the embryonic ω phase to isothermal ω phase transformation. Small angle neutron scattering (SANS) results indicates that the evolution of the isothermal ω phase goes through the increasing average size and aspect ratio from 24.7 to 47.0 nm and from 2.1 to 2.7 respectively, and the morphology evolution of the ω particle from ellipsoid to spindle-like. Moreover, the isothermal ω phase assists the α phase to nucleate at the ω/β interface, which involves the changes in elemental composition. The α phase is enriched in Al. Compared to the α phase, the element of Mo, V and Cr in the isothermal ω phase is lower. The Fe element is uniformly distributed in the isothermal ω phase and β matrix but lean in the α phase. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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14 pages, 2254 KiB  
Article
Biocompatibility and Cellular Behavior of TiNbTa Alloy with Adapted Rigidity for the Replacement of Bone Tissue
by Mercè Giner, Ernesto Chicardi, Alzenira de Fátima Costa, Laura Santana, María Ángeles Vázquez-Gámez, Cristina García-Garrido, Miguel Angel Colmenero, Francisco Jesús Olmo-Montes, Yadir Torres and María José Montoya-García
Metals 2021, 11(1), 130; https://doi.org/10.3390/met11010130 - 11 Jan 2021
Cited by 9 | Viewed by 1823
Abstract
In this work, the mechanical and bio-functional behavior of a TiNbTa alloy is evaluated as a potential prosthetic biomaterial used for cortical bone replacement. The results are compared with the reference Ti c.p. used as biomaterials for bone-replacement implants. The estimated mechanical behavior [...] Read more.
In this work, the mechanical and bio-functional behavior of a TiNbTa alloy is evaluated as a potential prosthetic biomaterial used for cortical bone replacement. The results are compared with the reference Ti c.p. used as biomaterials for bone-replacement implants. The estimated mechanical behavior for TiNbTa foams was also compared with the experimental Ti c.p. foams fabricated by the authors in previous studies. A TiNbTa alloy with a 20–30% porosity could be a candidate for the replacement of cortical bone, while levels of 80% would allow the manufacture of implants for the replacement of trabecular bone tissue. Regarding biocompatibility, in vitro TiNbTa, cellular responses (osteoblast adhesion and proliferation) were compared with cell growth in Ti c.p. samples. Cell adhesion (presence of filopodia) and propagation were promoted. The TiNbTa samples had a bioactive response similar to that of Ti c.p. However, TiNbTa samples show a better balance of bio-functional behavior (promoting osseointegration) and biomechanical behavior (solving the stress-shielding phenomenon and guaranteeing mechanical resistance). Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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23 pages, 5945 KiB  
Article
Structural Aspects and Characterization of Structure in the Processing of Titanium Grade4 Different Chips
by Krzysztof Topolski, Jakub Jaroszewicz and Halina Garbacz
Metals 2021, 11(1), 101; https://doi.org/10.3390/met11010101 - 06 Jan 2021
Cited by 4 | Viewed by 1817
Abstract
This study presents the structural aspects of the solid-state processing of various titanium chips. The structural characterization of: (1) commercial pure Ti in the as-received state, (2) manufactured chips, and (3) products of the chip processing are presented. Pure single-phase titanium Grade4 (Ti [...] Read more.
This study presents the structural aspects of the solid-state processing of various titanium chips. The structural characterization of: (1) commercial pure Ti in the as-received state, (2) manufactured chips, and (3) products of the chip processing are presented. Pure single-phase titanium Grade4 (Ti Gr4) was processed which, among all grades of pure titanium, is characterized by the lowest possible purity and the highest possible strength at the same time. Four geometries of chips were processed, i.e., chips after turning (thin and coarse), and chips after milling (thin and coarse). An unconventional plastic working method was applied to transform a dispersed form (chips) into solid, bulk metal in the form of rods without re-melting. The rods with a diameter of Ø8 mm and a length of about 500 mm were manufactured. Based on computer tomography and Archimedes measurements, it was found that the manufactured rods were consolidated and near fully dense. In turn, microscopy investigations proved that conventional, polycrystalline, grained structures were obtained. Only an insignificantly small number of internal defects were revealed, meaning that the obtained rods exhibited a proper structure typical for commercial titanium. Obtained materials, except of small surface inclusions, were fee of impurities. Whereas the results of the compression tests proved that the manufactured rods are characterized by new interatomic bonds, cohesion and plasticity analogous to those of titanium in the as-received state. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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18 pages, 4470 KiB  
Article
Improving the Mechanical Properties of a β-type Ti-Nb-Zr-Fe-O Alloy
by Vasile Danut Cojocaru, Anna Nocivin, Corneliu Trisca-Rusu, Alexandru Dan, Raluca Irimescu, Doina Raducanu and Bogdan Mihai Galbinasu
Metals 2020, 10(11), 1491; https://doi.org/10.3390/met10111491 - 09 Nov 2020
Cited by 11 | Viewed by 2204
Abstract
The influence of complex thermo-mechanical processing (TMP) on the mechanical properties of a Ti-Nb-Zr-Fe-O bio-alloy was investigated in this study. The proposed TMP program involves a schema featuring a series of severe plastic deformation (SPD) and solution treatment (STs). The purpose of this [...] Read more.
The influence of complex thermo-mechanical processing (TMP) on the mechanical properties of a Ti-Nb-Zr-Fe-O bio-alloy was investigated in this study. The proposed TMP program involves a schema featuring a series of severe plastic deformation (SPD) and solution treatment (STs). The purpose of this study was to find the proper parameter combination for the applied TMP and thus enhance the mechanical strength and diminish the Young’s modulus. The proposed chemical composition of the studied β-type Ti-alloy was conceived from already-appreciated Ti-Nb-Ta-Zr alloys with high β-stability by replacing the expensive Ta with more accessible Fe and O. These chemical additions are expected to better enhance β-stability and thus avoid the generation of ω, α’, and α” during complex TMP, as well as allow for the processing of a single bcc β-phase with significant grain diminution, increased mechanical strength, and a low elasticity value/Young’s modulus. The proposed TMP program considers two research directions of TMP experiments. For comparisons using structural and mechanical perspectives, the two categories of the experimental samples were analyzed using SEM microscopy and a series of tensile tests. The comparison also included some already published results for similar alloys. The analysis revealed the advantages and disadvantages for all compared categories, with the conclusions highlighting that the studied alloys are suitable for expanding the database of possible β-Ti bio-alloys that could be used depending on the specific requirements of different biomedical implant applications. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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24 pages, 13492 KiB  
Article
Effect of Strain Rate on Microstructure Evolution and Mechanical Behavior of Titanium-Based Materials
by Pavlo E. Markovsky, Jacek Janiszewski, Vadim I. Bondarchuk, Oleksandr O. Stasyuk, Dmytro G. Savvakin, Mykola A. Skoryk, Kamil Cieplak, Piotr Dziewit and Sergey V. Prikhodko
Metals 2020, 10(11), 1404; https://doi.org/10.3390/met10111404 - 22 Oct 2020
Cited by 21 | Viewed by 2816
Abstract
The goal of the present work is a systematic study on an influence of a strain rate on the mechanical response and microstructure evolution of the selected titanium-based materials, i.e., commercial pure titanium, Ti-6Al-4V alloy with lamellar and globular microstructures produced via a [...] Read more.
The goal of the present work is a systematic study on an influence of a strain rate on the mechanical response and microstructure evolution of the selected titanium-based materials, i.e., commercial pure titanium, Ti-6Al-4V alloy with lamellar and globular microstructures produced via a conventional cast and wrought technology, as well as Ti-6Al-4V fabricated using blended elemental powder metallurgy (BEPM). The quasi-static and high-strain-rate compression tests using the split Hopkinson pressure bar (SHPB) technique were performed and microstructures of the specimens were characterized before and after compression testing. The strain rate effect was analyzed from the viewpoint of its influence on the stress–strain response, including the strain energy, and a microstructure of the samples after compressive loading. It was found out that the Ti-6Al-4V with a globular microstructure is characterized by high strength and high plasticity (ensuring the highest strain energy) in comparison to alloy with a lamellar microstructure, whereas Ti6-Al-4V obtained with BEPM reveals the highest plastic flow stress with good plasticity at the same time. The microstructure observations reveal that a principal difference in high-strain-rate behavior of the tested materials could be explained by the nature of the boundaries between the structural components through which plastic deformation is transmitted: α/α boundaries prevail in the globular microstructure, while α/β boundaries prevail in the lamellar microstructure. The Ti-6Al-4V alloy obtained with BEPM due to a finer microstructure has a significantly better balance of strength and plasticity as compared with conventional Ti-6Al-4V alloy with a similar type of the lamellar microstructure. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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16 pages, 9096 KiB  
Article
Effect of Fe Content on the As-Cast Microstructures of Ti–6Al–4V–xFe Alloys
by Ling Ding, Rui Hu, Yulei Gu, Danying Zhou, Fuwen Chen, Lian Zhou and Hui Chang
Metals 2020, 10(8), 989; https://doi.org/10.3390/met10080989 - 22 Jul 2020
Cited by 7 | Viewed by 2530
Abstract
In this work, the evolution of the solidification microstructures of Ti–6Al–4V–xFe (x = 0.1, 0.3, 0.5, 0.7, 0.9) alloys fabricated by levitation melting was studied by combined simulative and experimental methods. The growth of grains as well as the composition distribution mechanisms during [...] Read more.
In this work, the evolution of the solidification microstructures of Ti–6Al–4V–xFe (x = 0.1, 0.3, 0.5, 0.7, 0.9) alloys fabricated by levitation melting was studied by combined simulative and experimental methods. The growth of grains as well as the composition distribution mechanisms during the solidification process of the alloy are discussed. The segregation of the Fe element at the grain boundaries promotes the formation of a local composition supercooling zone, thus inhibiting the mobility of the solid–liquid interface and making it easier for the grains to grow into dendrites. With the increase in Fe content, the grain size of the alloy decreased gradually, while the overall decreasing trend was mitigated. The segregation of Fe was more obvious than that of Al and V, and the increase in Fe content had less effect on the segregation of Al and V. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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12 pages, 6118 KiB  
Article
Microstructural Characterization of Friction-Stir Processed Ti-6Al-4V
by Sergey Mironov, Yutaka S. Sato, Hiroyuki Kokawa, Satoshi Hirano, Adam L. Pilchak and Sheldon Lee Semiatin
Metals 2020, 10(7), 976; https://doi.org/10.3390/met10070976 - 20 Jul 2020
Cited by 13 | Viewed by 3120
Abstract
The present work was undertaken to shed additional light on the globular-α microstructure produced during FSP of Ti-6Al-4V. To this end, the electron backscatter diffraction (EBSD) technique was employed to characterize the crystallographic aspects of such microstructure. In contrast to the previous reports [...] Read more.
The present work was undertaken to shed additional light on the globular-α microstructure produced during FSP of Ti-6Al-4V. To this end, the electron backscatter diffraction (EBSD) technique was employed to characterize the crystallographic aspects of such microstructure. In contrast to the previous reports in the literature, neither the texture nor the misorientation distribution in the α phase were random. Although the texture was weak, it showed a clear prevalence of the P1 and C-fiber simple-shear orientations, thus providing evidence for an increased activity of the prism-<a> and pyramidal <c+a> slip systems. In addition, the misorientation distribution exhibited a crystallographic preference of 60° and 90° boundaries. This observation was attributed to a partial α→β→α phase transformation during/following high-temperature deformation and the possible activation of mechanical twinning. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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19 pages, 14381 KiB  
Article
Hot Deformation Behavior and Processing Maps of Ti-6554 Alloy for Aviation Key Structural Parts
by Qi Liu, Zhaotian Wang, Hao Yang and Yongquan Ning
Metals 2020, 10(6), 828; https://doi.org/10.3390/met10060828 - 21 Jun 2020
Cited by 13 | Viewed by 2287
Abstract
With the development of the aviation industry, the performance requirements of materials for aviation large-scale structural parts are getting higher and higher. Ti-6554 alloy is the material of choice for aviation large-scale structural parts, but its forming process window is narrow and its [...] Read more.
With the development of the aviation industry, the performance requirements of materials for aviation large-scale structural parts are getting higher and higher. Ti-6554 alloy is the material of choice for aviation large-scale structural parts, but its forming process window is narrow and its microstructure is sensitive to process parameters, which affects the performance of the alloy. By adjusting the existing hot deformation process, it is of great significance to improve the properties of the alloy. Hot compression tests of Ti-6554 alloy were carried out at temperatures of 715–840 °C and strain rates of 0.001–1 s−1. The results show that the flow stress and peak stress increased significantly with the increase of strain rate. At the same strain rate, the strain required for the stress to reach the peak point is smaller with the temperature increases. When the deformation temperature is below the phase transition point, the volume fraction and size of primary α phase gradually decrease with the increase of deformation temperature, while when the temperature is above the phase transition point, with the increase of deformation temperature, β grains grow up gradually, and the grain boundary bending effect is more obvious. The hyperbolic-sine Arrhenius constitutive equation was established. The correlation coefficient between experimental data and model calculated data reached 0.994. It indicates that the stress constitutive model proposed in this study can accurately reflect the stress characteristics of Ti-6554 alloy. Based on the dynamic material model, the processing maps of the alloy were established. The optimum hot deformation parameters range of the alloy was determined by analyzing the processing maps: the deformation temperature range of 800–830 °C, the strain rate range of 0.001–0.01 s−1. Through the analysis of the processing maps, the instability regions in the process of cross-phase forging can be effectively avoided, and the performance of the forging can be effectively improved. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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10 pages, 5674 KiB  
Article
Ambivalent Role of Annealing in Tensile Properties of Step-Rolled Ti-6Al-4V with Ultrafine-Grained Structure
by Geonhyeong Kim, Taekyung Lee, Yongmoon Lee, Jae Nam Kim, Seong Woo Choi, Jae Keun Hong and Chong Soo Lee
Metals 2020, 10(5), 684; https://doi.org/10.3390/met10050684 - 22 May 2020
Cited by 4 | Viewed by 2547
Abstract
Step rolling can be used to mass-produce ultrafine-grained (UFG) Ti-6Al-4V sheets. This study clarified the effect of subsequent annealing on the tensile properties of step-rolled Ti-6Al-4V at room temperature (RT) and elevated temperature. The step-rolled alloy retained its UFG structure after subsequent annealing [...] Read more.
Step rolling can be used to mass-produce ultrafine-grained (UFG) Ti-6Al-4V sheets. This study clarified the effect of subsequent annealing on the tensile properties of step-rolled Ti-6Al-4V at room temperature (RT) and elevated temperature. The step-rolled alloy retained its UFG structure after subsequent annealing at 500–600 °C. The RT ductility of the step-rolled alloy increased regardless of annealing temperature, but strengthening was only attained by annealing at 500 °C. In contrast, subsequent annealing rarely improved the elevated-temperature tensile properties. The step-rolled Ti-6Al-4V alloy without the annealing showed the highest elongation to failure of 960% at 700 °C and a strain rate of 10−3 s−1. The ambivalent effect of annealing on RT and elevated-temperature tensile properties is a result of microstructural features, such as dislocation tangles, subgrains, phases, and continuous dynamic recrystallization. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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12 pages, 5744 KiB  
Article
Reaction Layer Analysis of In Situ Reinforced Titanium Composites: Influence of the Starting Material Composition on the Mechanical Properties
by Isabel Montealegre-Meléndez, Cristina Arévalo, Ana M. Beltrán, Michael Kitzmantel, Erich Neubauer and Eva María Pérez Soriano
Metals 2020, 10(2), 265; https://doi.org/10.3390/met10020265 - 18 Feb 2020
Cited by 1 | Viewed by 1843
Abstract
This study aims at the analysis of the reaction layer between titanium matrices and reinforcements: B4C particles and/or intermetallic TixAly. Likewise, the importance of these reactions was observed; this was particularly noteworthy as regard coherence with the [...] Read more.
This study aims at the analysis of the reaction layer between titanium matrices and reinforcements: B4C particles and/or intermetallic TixAly. Likewise, the importance of these reactions was observed; this was particularly noteworthy as regard coherence with the obtained results and the parameters tested. Accordingly, five starting material compositions were studied under identical processing parameters via inductive hot pressing at 1100 °C for 5 min in vacuum conditions. The results revealed how the intermetallics limited the formation of secondary phases (TiC and TiB) created from the B and C source. In this respect, the percentages of TiB and TiC slightly varied when the intermetallic was included in the matrix as prealloyed particles. On the contrary, if the intermetallics appeared in situ by the addition of Ti-Al powder in the starting blend, their content was lesser. The mechanical properties values and the tribology behaviour might deviate, depending on the percentage of the secondary phases formed and its distribution in the matrix. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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10 pages, 3968 KiB  
Communication
Grain Refinement of Ti-15Mo-3Al-2.7Nb-0.2Si Alloy with the Rotation of TiB Whiskers by Powder Metallurgy and Canned Hot Extrusion
by Jiabin Hou, Lin Gao, Guorong Cui, Wenzhen Chen, Wencong Zhang and Wenguang Tian
Metals 2020, 10(1), 126; https://doi.org/10.3390/met10010126 - 15 Jan 2020
Cited by 5 | Viewed by 2354
Abstract
In situ synthesized TiB whiskers (TiBw) reinforced Ti-15Mo-3Al-2.7Nb-0.2Si alloys were successfully manufactured by pre-sintering and canned hot extrusion via adding TiB2 powders. During pre-sintering, most TiB2 were reacted with Ti atoms to produce TiB. During extrusion, the continuous dynamic recrystallization (CDRX) [...] Read more.
In situ synthesized TiB whiskers (TiBw) reinforced Ti-15Mo-3Al-2.7Nb-0.2Si alloys were successfully manufactured by pre-sintering and canned hot extrusion via adding TiB2 powders. During pre-sintering, most TiB2 were reacted with Ti atoms to produce TiB. During extrusion, the continuous dynamic recrystallization (CDRX) of β grains was promoted with the rotation of TiBw, and CDRXed grains were strongly inhibited by TiBw with hindering dislocation motion. Eventually, the grain sizes of composites decreased obviously. Furthermore, the stress transmitted from the matrix to TiBw for strengthening in a tensile test, besides grain refinement. Meanwhile, the fractured TiBw and microcracks around them contributed to fracturing. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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17 pages, 16646 KiB  
Article
Reconstruction of Complex Zygomatic Bone Defects Using Mirroring Coupled with EBM Fabrication of Titanium Implant
by Khaja Moiduddin, Syed Hammad Mian, Usama Umer, Naveed Ahmed, Hisham Alkhalefah and Wadea Ameen
Metals 2019, 9(12), 1250; https://doi.org/10.3390/met9121250 - 22 Nov 2019
Cited by 7 | Viewed by 4208
Abstract
Reconstruction of zygomatic complex defects is a surgical challenge, owing to the accurate restoration of structural symmetry as well as facial projection. Generally, there are many available techniques for zygomatic reconstruction, but they hardly achieve aesthetic and functional properties. To our knowledge, there [...] Read more.
Reconstruction of zygomatic complex defects is a surgical challenge, owing to the accurate restoration of structural symmetry as well as facial projection. Generally, there are many available techniques for zygomatic reconstruction, but they hardly achieve aesthetic and functional properties. To our knowledge, there is no such study on zygomatic titanium bone reconstruction, which involves the complete steps from patient computed tomography scan to the fabrication of titanium zygomatic implant and evaluation of implant accuracy. The objective of this study is to propose an integrated system methodology for the reconstruction of complex zygomatic bony defects using titanium comprising several steps, right from the patient scan to implant fabrication while maintaining proper aesthetic and facial symmetry. The integrated system methodology involves computer-assisted implant design based on the patient computed tomography data, the implant fitting accuracy using three-dimensional comparison techniques, finite element analysis to investigate the biomechanical behavior under loading conditions, and finally titanium fabrication of the zygomatic implant using state-of-the-art electron beam melting technology. The resulting titanium implant has a superior aesthetic appearance and preferable biocompatibility. The customized mirrored implant accurately fit on the defective area and restored the tumor region with inconsequential inconsistency. Moreover, the outcome from the two-dimensional analysis provided a good accuracy within 2 mm as established through physical prototyping. Thus, the designed implant produced faultless fitting, favorable symmetry, and satisfying aesthetics. The simulation results also demonstrated the load resistant ability of the implant with max stress within 1.76 MPa. Certainly, the mirrored and electron beam melted titanium implant can be considered as the practical alternative for a bone substitute of complex zygomatic reconstruction. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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11 pages, 5707 KiB  
Article
Corrosion and Tensile Behaviors of Ti-4Al-2V-1Mo-1Fe and Ti-6Al-4V Titanium Alloys
by Yanxin Qiao, Daokui Xu, Shuo Wang, Yingjie Ma, Jian Chen, Yuxin Wang and Huiling Zhou
Metals 2019, 9(11), 1213; https://doi.org/10.3390/met9111213 - 11 Nov 2019
Cited by 30 | Viewed by 3870
Abstract
X-ray diffraction (XRD), scanning electron microscope (SEM), immersion, electrochemical, and tensile tests were employed to analyze the phase constitution, microstructure, corrosion behaviors, and tensile properties of a Ti-6Al-4V alloy and a newly-developed low cost titanium alloy Ti-4Al-2V-1Mo-1Fe. The results showed that both the [...] Read more.
X-ray diffraction (XRD), scanning electron microscope (SEM), immersion, electrochemical, and tensile tests were employed to analyze the phase constitution, microstructure, corrosion behaviors, and tensile properties of a Ti-6Al-4V alloy and a newly-developed low cost titanium alloy Ti-4Al-2V-1Mo-1Fe. The results showed that both the Ti-6Al-4V and Ti-4Al-2V-1Mo-1Fe alloys were composed of α and β phases. The volume fractions of β phase for these two alloys were 7.4% and 47.3%, respectively. The mass losses after 180-day immersion tests in 3.5 wt.% NaCl solution of these alloys were negligible. The corrosion resistance of the Ti-4Al-2V-1Mo-1Fe alloy was higher than that of the Ti-6Al-4V alloy. The tensile tests showed that the Ti-4Al-2V-1Mo-1Fe alloy presented a slightly higher strength but a lower ductility compared to the Ti-6Al-4V alloy. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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10 pages, 3105 KiB  
Article
Mechanical Behavior and Microstructure Evolution of a Ti-15Mo/TiB Titanium–Matrix Composite during Hot Deformation
by Sergey Zherebtsov, Maxim Ozerov, Margarita Klimova, Dmitry Moskovskikh, Nikita Stepanov and Gennady Salishchev
Metals 2019, 9(11), 1175; https://doi.org/10.3390/met9111175 - 31 Oct 2019
Cited by 23 | Viewed by 2995
Abstract
A Ti-15Mo/TiB titanium–matrix composite (TMC) was produced by spark plasma sintering at 1400 °C under a load of 40 MPa for 15 min using a Ti-14.25(wt.)%Mo-5(wt.)%TiB2 powder mixture. Microstructure evolution and mechanical behavior of the composite were studied during uniaxial compression at [...] Read more.
A Ti-15Mo/TiB titanium–matrix composite (TMC) was produced by spark plasma sintering at 1400 °C under a load of 40 MPa for 15 min using a Ti-14.25(wt.)%Mo-5(wt.)%TiB2 powder mixture. Microstructure evolution and mechanical behavior of the composite were studied during uniaxial compression at room temperature and in a temperature range of 500–1000 °C. At room temperature, the composite showed a combination of high strength (the yield strength was ~1500 MPa) and good ductility (~22%). The microstructure evolution of the Ti-15Mo matrix was associated with the development of dynamic recovery at 500–700 °C and dynamic recrystallization at higher temperatures (≥800 °C). The apparent activation energy of the plastic deformation was calculated and a processing map for the TMC was constructed using the obtained results. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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Review

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17 pages, 1971 KiB  
Review
Martensite Formation and Decomposition during Traditional and AM Processing of Two-Phase Titanium Alloys—An Overview
by Maciej Motyka
Metals 2021, 11(3), 481; https://doi.org/10.3390/met11030481 - 14 Mar 2021
Cited by 53 | Viewed by 8235
Abstract
Titanium alloys have been considered as unique materials for many years. Even their microstructure and operational properties have been well known and described in details, the new technologies introduced—e.g., 3D printing—have restored the need for further research in this area. It is understood [...] Read more.
Titanium alloys have been considered as unique materials for many years. Even their microstructure and operational properties have been well known and described in details, the new technologies introduced—e.g., 3D printing—have restored the need for further research in this area. It is understood that martensitic transformation is usually applied in heat treatment of hardenable alloys (e.g., Fe alloys), but in the case of titanium alloys, it also occurs during the thermomechanical processing or advanced additive manufacturing. The paper summarizes previous knowledge on martensite formation and decomposition processes in two-phase titanium alloys. It emphasizes their important role in microstructure development during conventional and modern industrial processing. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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Other

17 pages, 4443 KiB  
Technical Note
An Intermetallic NiTi-Based Shape Memory Coil Spring for Actuator Technologies
by Ganesh Shimoga, Tae-Hoon Kim and Sang-Youn Kim
Metals 2021, 11(8), 1212; https://doi.org/10.3390/met11081212 - 29 Jul 2021
Cited by 13 | Viewed by 3668
Abstract
Amongst various intermetallic shape memory alloys (SMAs), nickel–titanium-based SMAs (NiTi) are known for their unique elastocaloric property. This widely used shape remembering material demonstrates excellent mechanical and electrical properties with superior corrosion resistance and super-long fatigue life. The straight-drawn wire form of NiTi [...] Read more.
Amongst various intermetallic shape memory alloys (SMAs), nickel–titanium-based SMAs (NiTi) are known for their unique elastocaloric property. This widely used shape remembering material demonstrates excellent mechanical and electrical properties with superior corrosion resistance and super-long fatigue life. The straight-drawn wire form of NiTi has a maximum restorable strain limit of ~4%. However, a maximum linear strain of ~20% can be attained in its coil spring structure. Various material/mechanical engineers have widely exploited this superior mechanic characteristic and stress-triggered heating/cooling efficiency of NiTi to design smart engineering structures, especially in actuator technologies. This short technical note reflects the characteristics of the NiTi coil spring structure with its phase transformations and thermal transformation properties. The micro-actuators based on NiTi have been found to be possible, suggesting uses from biomedical to advanced high-tech applications. In recent years, the technical advancements in modular robotic systems involving NiTi-based SMAs have gained speculative commercial interest. Full article
(This article belongs to the Special Issue Titanium Alloys and Titanium-Based Matrix Composites)
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