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12 pages, 10649 KiB

Open AccessArticle

Microstructure of the Advanced Titanium Alloy VT8M-1 Subjected to Rotary Swaging

by Grigory S. Dyakonov, Tatyana V. Yakovleva, Sergei Y. Mironov, Andrey G. Stotskiy, Iulia M. Modina and Irina P. Semenova

Materials 2023, 16(21), 6851; https://doi.org/10.3390/ma16216851 - 25 Oct 2023

Cited by 1 | Viewed by 673

Abstract

In this study, the microstructural behavior of the advanced Ti-5.7Al-3.8Mo-1.2Zr-1.3Sn-0.15Si (VT8M-1) alloy during rotary swaging (RS) was investigated. VT8M-1 has increased heat resistance and is considered a replacement for the Ti-6Al-4V alloy. It was shown that, during RS, the evolution of the primary [...] Read more.

In this study, the microstructural behavior of the advanced Ti-5.7Al-3.8Mo-1.2Zr-1.3Sn-0.15Si (VT8M-1) alloy during rotary swaging (RS) was investigated. VT8M-1 has increased heat resistance and is considered a replacement for the Ti-6Al-4V alloy. It was shown that, during RS, the evolution of the primary a phase is characterized by the formation of predominantly low-angle boundaries according to the mechanism of continuous dynamic recrystallization. The density of low-angle boundaries increases three times: from 0.38 µm⁻¹ to 1.21 µm⁻¹ after RS. The process of spheroidization of the lamellar (a + b) component is incomplete. The average size of globular a and b particles was 0.3 μm (TEM). It is shown that the microstructures after RS (ε = 1.56) and equal-channel angular pressing (ECAP) (ε = 1.4) are significantly different. The temperature–velocity regime and the predominance of shear deformations during ECAP contributed to a noticeable refinement of the primary a-phase and a more complete development of globularization of the lamellar (a+b) component. EBSD studies have shown that RS leads to the formation of a structure with a higher density of low- and high-angle boundaries compared to the structure after ECAP. The results are useful for predicting alloy microstructure in the production of long rods that are further used in forging operations. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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12 pages, 2534 KiB

Open AccessArticle

Structural Aspects of the Formation of Multilayer Composites from Dissimilar Materials upon High-Pressure Torsion

by Roman Sundeev, Anna Shalimova, Stanislav Rogachev, Olga Chernogorova, Alexander Glezer, Alexey Ovcharov, Igor Karateev and Natalia Tabachkova

Materials 2023, 16(10), 3849; https://doi.org/10.3390/ma16103849 - 19 May 2023

Cited by 4 | Viewed by 784

Abstract

A multi-metal composite was consolidated from the Ti₅₀Ni₂₅Cu₂₅ and Fe₅₀Ni₃₃B₁₇ alloys by room-temperature high-pressure torsion (HPT). The structural research methods used in this study were X-ray diffractometry, high-resolution transmission electron microscopy, scanning electron [...] Read more.

A multi-metal composite was consolidated from the Ti₅₀Ni₂₅Cu₂₅ and Fe₅₀Ni₃₃B₁₇ alloys by room-temperature high-pressure torsion (HPT). The structural research methods used in this study were X-ray diffractometry, high-resolution transmission electron microscopy, scanning electron microscopy with an electron microprobe analyzer in the mode of backscattered electrons, and the measurement of indentation hardness and modulus of the composite constituents. The structural aspects of the bonding process have been examined. The method of joining materials using their coupled severe plastic deformation has been established to play a leading role in the consolidation of the dissimilar layers upon HPT. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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18 pages, 4948 KiB

Open AccessArticle

Effect of Copper Segregation at Low-Angle Grain Boundaries on the Mechanisms of Plastic Relaxation in Nanocrystalline Aluminum: An Atomistic Study

by Vasiliy Krasnikov, Alexander Mayer, Polina Bezborodova and Marat Gazizov

Materials 2023, 16(8), 3091; https://doi.org/10.3390/ma16083091 - 13 Apr 2023

Cited by 3 | Viewed by 1316

Abstract

The paper studies the mechanisms of plastic relaxation and mechanical response depending on the concentration of Cu atoms at grain boundaries (GBs) in nanocrystalline aluminum with molecular dynamics simulations. A nonmonotonic dependence of the critical resolved shear stress on the Cu content at [...] Read more.

The paper studies the mechanisms of plastic relaxation and mechanical response depending on the concentration of Cu atoms at grain boundaries (GBs) in nanocrystalline aluminum with molecular dynamics simulations. A nonmonotonic dependence of the critical resolved shear stress on the Cu content at GBs is shown. This nonmonotonic dependence is related to the change in plastic relaxation mechanisms at GBs. At a low Cu content, GBs slip as dislocation walls, whereas an increase in Cu content involves a dislocation emission from GBs and grain rotation with GB sliding. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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14 pages, 11262 KiB

Open AccessArticle

Microstructural Assessment, Mechanical and Corrosion Properties of a Mg-Sr Alloy Processed by Combined Severe Plastic Deformation

by Ruslan K. Nafikov, Olga B. Kulyasova, Ganjina D. Khudododova and Nariman A. Enikeev

Materials 2023, 16(6), 2279; https://doi.org/10.3390/ma16062279 - 12 Mar 2023

Cited by 2 | Viewed by 1204

Abstract

The development of high-performance biodegradable alloys with controllable corrosion rates to be used for manufacturing advanced implants is a hot topic of modern materials science and biomedicine. This work features the changes in microstructure, corrosion behavior and mechanical properties of the Mg-2 wt.%Sr [...] Read more.

The development of high-performance biodegradable alloys with controllable corrosion rates to be used for manufacturing advanced implants is a hot topic of modern materials science and biomedicine. This work features the changes in microstructure, corrosion behavior and mechanical properties of the Mg-2 wt.%Sr alloy progressively induced by equal-channel angular pressing, high-pressure torsion and annealing. We show that such processing leads to significant microstructure refinement including diminishing grain size, defect accumulation and fragmentation of the initial eutectics. We demonstrate that the application of severe plastic deformation and heat treatment is capable of considerably enhancing the mechanical and corrosion performance of a biodegradable alloy of the Mg-Sr system. The best trade-off between strength, plasticity and the corrosion resistance has been achieved by annealing of the Mg-Sr alloy subjected to combined severe plastic deformation processing. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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16 pages, 5348 KiB

Open AccessArticle

Gradient Microstructure and Texture Formation in a Metastable Austenitic Stainless Steel during Cold Rotary Swaging

by Dmitrii Panov, Egor Kudryavtsev, Stanislav Naumov, Denis Klimenko, Ruslan Chernichenko, Vladimir Mirontsov, Nikita Stepanov, Sergey Zherebtsov, Gennady Salishchev and Alexey Pertcev

Materials 2023, 16(4), 1706; https://doi.org/10.3390/ma16041706 - 17 Feb 2023

Cited by 8 | Viewed by 1271

Abstract

The paper aimed to study the evolution of the microstructure and texture gradient of a 321-type metastable austenitic stainless steel during cold rotary swaging. Cold rotary swaging was carried out with a reduction of up to 90% at ambient temperature. Pronounced gradients of [...] Read more.

The paper aimed to study the evolution of the microstructure and texture gradient of a 321-type metastable austenitic stainless steel during cold rotary swaging. Cold rotary swaging was carried out with a reduction of up to 90% at ambient temperature. Pronounced gradients of the α’-martensite volume fraction, the axial texture of austenite (⟨111⟩ and ⟨001⟩) and α’-martensite (⟨101⟩), and non-uniform microhardness distribution along the rod diameter were obtained after a reduction of 80–90%. According to the finite element analysis, moderate tensile stresses were attained in the center, whereas high compressive stresses operated at the edge. Due to water cooling of the rod surface and heating of the rod center during processing, a temperature gradient was also derived. Features of strain-induced martensitic transformation, microstructure and texture evolution, and non-uniform hardening during cold rotary swaging were discussed. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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19 pages, 9464 KiB

Open AccessArticle

Phase Equilibria of the In–Pd–Sn System at 500 °C and 800 °C: Experimental Study and CALPHAD Modeling

by Alexandr S. Pavlenko, Elizaveta G. Kabanova, Maria A. Kareva, Evgeniya A. Ptashkina, Alexander L. Kustov, Galina P. Zhmurko and Victor N. Kuznetsov

Materials 2023, 16(4), 1690; https://doi.org/10.3390/ma16041690 - 17 Feb 2023

Cited by 3 | Viewed by 1167

Abstract

Phase equilibria in the In–Pd–Sn system were investigated by a combination of key experiments and thermodynamic modeling. Partial isothermal sections at 500 °C and 800 °C of the In–Pd–Sn system for Pd contents above 66 at.% have been plotted experimentally using scanning electron [...] Read more.

Phase equilibria in the In–Pd–Sn system were investigated by a combination of key experiments and thermodynamic modeling. Partial isothermal sections at 500 °C and 800 °C of the In–Pd–Sn system for Pd contents above 66 at.% have been plotted experimentally using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX) and X-ray diffraction (XRD). The solubility of the third component in binary compounds InPd₃ and Pd₃Sn was determined. The new ternary compound τ₁ was found in Pd contents ranging from 20 to 25 at.% and at Sn contents varying from 5 to approximately 17 at.% Sn. This compound crystallizes in an Al₃Ti-type tetragonal structure. Isostructural InPd₂ and Pd₂Sn phases from the In–Pd and Pd–Sn binary compositions form a continuous phase field in the ternary system at both temperatures. The temperatures of the solidus, liquidus, and phase transitions of the alloys along the Pd–In50Sn50 line were measured using DTA/DSC. Thermodynamic calculation of the In–Pd–Sn ternary system is performed using the CALPHAD method using the Thermo-Calc^® software. The thermodynamic properties of the disordered fcc and liquid phases were described by the Redlich–Kister–Muggianu model. To describe intermetallic phases, namely, InPd₃, Pd₃Sn, τ₁ and Pd₂(In_xSn_1−x), a two-sublattice models was used. Thermodynamic description of the In–Pd–Sn system obtained in this study is in good agreement both with our results and the published experimental data Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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13 pages, 4013 KiB

Open AccessArticle

Enhanced Fatigue Limit in Ultrafine-Grained Ferritic–Martensitic Steel

by Marina A. Nikitina, Rinat K. Islamgaliev, Artur V. Ganeev and Aleksandra A. Frik

Materials 2023, 16(4), 1632; https://doi.org/10.3390/ma16041632 - 15 Feb 2023

Viewed by 1208

Abstract

The influence of the ultrafine-grained (UFG) structure on the fatigue endurance limit and the nature of fatigue failure have been studied. It is shown that the formation of the UFG structure containing carbides and the coincidence site lattice relationship (CSL) and twin boundaries [...] Read more.

The influence of the ultrafine-grained (UFG) structure on the fatigue endurance limit and the nature of fatigue failure have been studied. It is shown that the formation of the UFG structure containing carbides and the coincidence site lattice relationship (CSL) and twin boundaries leads to an increase in the fatigue endurance limit. To study the mechanisms of fatigue failure, scanning and transmission electron microscopy and X-ray diffraction analysis were used. Studies have shown that the formation of the UFG structure as a result of rolling and subsequent heat treatment above the temperature of the ferrite/austenite phase transition leads to an increase in the fatigue endurance limit by more than 70%, from 475 to 800 MPa, compared to coarse-grained samples. The dynamic aging observed during fatigue tests was more pronounced in materials with a UFG microstructure. The influence of the CSL and twin boundaries on the nature of the fatigue failure of ferritic–martensitic steel is discussed. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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11 pages, 6663 KiB

Open AccessArticle

Superplastic Behavior and Microstructural Features of the VT6 Titanium Alloy with an Ultrafine-Grained Structure during Upsetting

by Grigory S. Dyakonov, Andrey G. Stotskiy, Iuliia M. Modina and Irina P. Semenova

Materials 2023, 16(4), 1439; https://doi.org/10.3390/ma16041439 - 08 Feb 2023

Cited by 5 | Viewed by 1142

Abstract

In this paper, the superplastic behavior of the two-phase titanium alloy VT6 with an ultrafine-grained (UFG) structure produced by equal-channel angular pressing is examined. The deformation of specimens with a UFG structure was performed by upsetting in a temperature range of 650–750 °C [...] Read more.

In this paper, the superplastic behavior of the two-phase titanium alloy VT6 with an ultrafine-grained (UFG) structure produced by equal-channel angular pressing is examined. The deformation of specimens with a UFG structure was performed by upsetting in a temperature range of 650–750 °C and strain rate range of 1 × 10⁻⁴–5 × 10⁻¹ s⁻¹. Under these conditions, an increased strain-rate sensitivity coefficient m was observed. The calculation of apparent activation energy showed values in a range of 160–200 kJ/mol while the superplastic flow of the VT6 alloy was occurring. When superplastic behavior (SPB) was impeded, the energy Q grew considerably, indicating a change in mechanism from grain-boundary sliding (GBS) to bulk diffusion. A change in temperature and strain rate influenced the development of superplastic flow and the balance of relaxation processes. Microstructural analysis shows that the UFG state is preserved at upsetting temperatures of 650 and 700 °C. A decrease in strain rate and/or an increase in upsetting temperature promoted a more active development of recrystallization and grain growth, as well as α₂-phase formation. In a certain temperature and strain-rate range of the UFG VT6 alloy, α₂-phase plates were found, the formation of which was controlled by diffusion. The effect of the α₂-phase on the alloy’s mechanical behavior is discussed. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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11 pages, 9306 KiB

Open AccessArticle

Effect of the Texture of the Ultrafine-Grained Ti-6Al-4V Titanium Alloy on Impact Toughness

by Iuliia M. Modina, Grigory S. Dyakonov, Andrey G. Stotskiy, Tatyana V. Yakovleva and Irina P. Semenova

Materials 2023, 16(3), 1318; https://doi.org/10.3390/ma16031318 - 03 Feb 2023

Cited by 7 | Viewed by 1410

Abstract

In this work, the strength properties and impact toughness of the ultrafine-grained (UFG) Ti-6Al-4V titanium alloy produced by severe plastic deformation (SPD) in combination with upsetting were studied, depending on the direction of crack propagation. In the billets processed by equal-channel angular pressing [...] Read more.

In this work, the strength properties and impact toughness of the ultrafine-grained (UFG) Ti-6Al-4V titanium alloy produced by severe plastic deformation (SPD) in combination with upsetting were studied, depending on the direction of crack propagation. In the billets processed by equal-channel angular pressing (ECAP), the presence of anisotropy of ultimate tensile strength (UTS) and ductility was observed, conditioned by the formation of a metallographic and crystallographic texture. At the same time, the ECAP-processed UFG alloy exhibited satisfactory values of impact toughness, ~0.42 MJ/m². An additional upsetting of the ECAP-processed billet simulated the processes of shape forming/die forging and was accompanied by the development of recovery and recrystallization. This provided the “blurring” of texture and a reduction in the anisotropy of UTS and ductility, but a difference in impact toughness in several directions of fracture was still observed. It is shown that texture evolution during upsetting provided a significant increase in the crack propagation energy. The relationship between microstructure, texture and mechanical properties in different sections of the material under study is discussed. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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21 pages, 9804 KiB

Open AccessArticle

Macro- and Microstructure of In Situ Composites Prepared by Friction Stir Processing of AA5056 Admixed with Copper Powders

by Valery Rubtsov, Andrey Chumaevskii, Anastasija Gusarova, Evgeny Knyazhev, Denis Gurianov, Anna Zykova, Tatiana Kalashnikova, Andrey Cheremnov, Nikolai Savchenko, Andrey Vorontsov, Veronika Utyaganova, Evgeny Kolubaev and Sergei Tarasov

Materials 2023, 16(3), 1070; https://doi.org/10.3390/ma16031070 - 26 Jan 2023

Cited by 5 | Viewed by 1276

Abstract

This paper is devoted to using multi-pass friction stir processing (FSP) for admixing 1.5 to 30 vol.% copper powders into an AA5056 matrix for the in situ fabrication of a composite alloy reinforced by Al-Cu intermetallic compounds (IMC). Macrostructurally inhomogeneous stir zones have [...] Read more.

This paper is devoted to using multi-pass friction stir processing (FSP) for admixing 1.5 to 30 vol.% copper powders into an AA5056 matrix for the in situ fabrication of a composite alloy reinforced by Al-Cu intermetallic compounds (IMC). Macrostructurally inhomogeneous stir zones have been obtained after the first FSP passes, the homogeneity of which was improved with the following FSP passes. As a result of stirring the plasticized AA5056, the initial copper particle agglomerates were compacted into large copper particles, which were then simultaneously saturated by aluminum. Microstructural investigations showed that various phases such as α-Al(Cu), α-Cu(Al) solid solutions, Cu₃Al and CuAl IMCs, as well as both S and S’-Al₂CuMg precipitates have been detected in the AA5056/Cu stir zone, depending upon the concentration of copper and the number of FSP passes. The number of IMCs increased with the number of FSP passes, enhancing microhardness by 50–55%. The effect of multipass FSP on tensile strength, yield stress and strain-to-fracture was analyzed. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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10 pages, 3315 KiB

Open AccessArticle

Deformation Behavior under Tension with Pulse Current of Ultrafine-Grain and Coarse-Grain CP Titanium

by Vladimir Stolyarov, Oleg Korolkov, Alexander Pesin and George Raab

Materials 2023, 16(1), 191; https://doi.org/10.3390/ma16010191 - 25 Dec 2022

Cited by 6 | Viewed by 1425

Abstract

The problem of the real existence of the electroplastic effect during deformation of metallic materials of different nature is still relevant. At the same time, the influence of structure refinement is not considered enough. In this work, the deformation behavior of ultrafine-grained (UFG) [...] Read more.

The problem of the real existence of the electroplastic effect during deformation of metallic materials of different nature is still relevant. At the same time, the influence of structure refinement is not considered enough. In this work, the deformation behavior of ultrafine-grained (UFG) titanium Grade 4 is compared with that of coarse-grained (CG) titanium under tension with pulse current of the low duty cycle. The deformation curves of both structure states are presented for different regimes of pulsed current and thermal heating from an external source. Structure studies by optical and scanning electron microscopy, as well as microhardness measurements have been carried out. It is shown that Grade 4 titanium under tension accompanied by pulsed current exhibits electroplastic effect (EPE) in the form of a flow stress reduction. EPE in UFG state is much stronger than in CG state. An increase in the density and duration of the current pulse leads to a multiple decrease in the flow stresses in CG and UFG titanium. The contribution in the flow stress reduction from heating by an external source was less than that from tension with pulse current at the same temperatures. The impact of pulsed current during tension does not influence microhardness and grain size. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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13 pages, 2533 KiB

Open AccessArticle

Some Slippage Issues in High-Pressure Torsion Using Cu and Ti Samples as an Example

by Dmitriy Gunderov, Rashid Asfandiyarov, Vyacheslav Titov, Sofia Gunderova and Vasily Astanin

Materials 2023, 16(1), 162; https://doi.org/10.3390/ma16010162 - 24 Dec 2022

Cited by 2 | Viewed by 1139

Abstract

The effect of slippage during High Pressure Torsion (HPT) of technically pure Ti and pure Cu samples was investigated. The “joint torsion of the disk halves” method was used to evaluate the effect of slippage. It was shown that slippage starts already at [...] Read more.

The effect of slippage during High Pressure Torsion (HPT) of technically pure Ti and pure Cu samples was investigated. The “joint torsion of the disk halves” method was used to evaluate the effect of slippage. It was shown that slippage starts already at the early stages of HPT. With a further increase in the number of revolutions n, the slippage effect increases, and no torsional deformation occurs after n = 5. The slippage effect is explained by analyzing the surface friction forces between the sample and the anvil. However, studies via TEM and XRD have shown that the structure of Ti samples after HPT at the investigated conditions is grinded to a nanocrystalline state. A structure is formed in Ti similar to that observed after HPT by other authors. The dislocation density increases with increasing HPT degree from n = 5 to n = 10 revolutions, despite slippage. Consequently, despite slippage at HPT at n ≥ 5, deformation still occurs. The following assumptions are made to explain the accumulated strain in the sample at HPT. It is assumed that the planes of the upper and lower anvil during HPT are at a slight inclination relative to each other. Computer modeling using the Deform 3D software package has shown that this leads to the accumulations of significant strain during HPT. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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9 pages, 5695 KiB

Open AccessArticle

Dissimilar Friction Stir Welding of AA2519 and AA5182

by Ivan S. Zuiko, Sergey Malopheyev, Sergey Mironov and Rustam Kaibyshev

Materials 2022, 15(24), 8776; https://doi.org/10.3390/ma15248776 - 08 Dec 2022

Cited by 1 | Viewed by 1019

Abstract

In this study, the friction-stir welding (FSW) technique was successfully applied for joining of AA2519 to AA5181 alloy. Microstructure and mechanical properties of dissimilar FSW joints were investigated by optical microscopy, microhardness, and tensile testing. The deformation behaviour of the welded joints was [...] Read more.

In this study, the friction-stir welding (FSW) technique was successfully applied for joining of AA2519 to AA5181 alloy. Microstructure and mechanical properties of dissimilar FSW joints were investigated by optical microscopy, microhardness, and tensile testing. The deformation behaviour of the welded joints was elucidated via the digital image correlation technique. After welding, the ultimate tensile strength of joints was ~300 MPa and ductility was ~16%. The microhardness values observed at the stir zone were higher than those in the base material AA5182. The produced welds demonstrate nearly 100% (based on AA5182) joint efficiency. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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14 pages, 6837 KiB

Open AccessArticle

Microstructure and Mechanical Properties of β-Titanium Ti-15Mo Alloy Produced by Combined Processing including ECAP-Conform and Drawing

by Svetlana A. Gatina, Veronika V. Polyakova, Alexander V. Polyakov and Irina P. Semenova

Materials 2022, 15(23), 8666; https://doi.org/10.3390/ma15238666 - 05 Dec 2022

Cited by 2 | Viewed by 1340

Abstract

At present, researchers pay great attention to the development of metastable β-titanium alloys. A task of current importance is the enhancement of their strength and fatigue properties. An efficient method for increasing the strength of such alloys could be severe plastic deformation. The [...] Read more.

At present, researchers pay great attention to the development of metastable β-titanium alloys. A task of current importance is the enhancement of their strength and fatigue properties. An efficient method for increasing the strength of such alloys could be severe plastic deformation. The object of this study was a medical metastable β-titanium alloy Ti-15Mo (ASTM F2066). The alloy in the (α + β) state was for the first time deformed by combined processing, including equal channel angular pressing-conform and drawing. Such processing enabled the production of long-length rods with a length of 1500 mm. The aim of the work was to study the effect of the combined processing on the alloy’s microstructure and mechanical properties. An ultrafine-grained structure with an average size of structural elements less than 100 nm was obtained. At the same time, high strength and ductility (σ_uts = 1590 MPa, δ = 10%) were achieved, which led to a record increase in the endurance limit (σ₋₁ = 710 MPa) under tension-compression terms. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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12 pages, 2981 KiB

Open AccessArticle

Effects of Severe Plastic Deformation and Ultrasonic Treatment on the Structure, Strength, and Corrosion Resistance of Mg-Al-Zn Alloy

by Denis A. Aksenov, Ayrat A. Nazarov, Georgiy I. Raab, Arseniy G. Raab, Elvira I. Fakhretdinova, Rashid N. Asfandiyarov, Maria A. Shishkunova and Yulia R. Sementeeva

Materials 2022, 15(20), 7200; https://doi.org/10.3390/ma15207200 - 15 Oct 2022

Cited by 2 | Viewed by 1423

Abstract

Nowadays, there is a great demand for increasing the strength and corrosion resistance of magnesium alloys for their wider use in machine engineering, oil industry, and medicine. This paper is devoted to a study on the effects of the combined process of reduction [...] Read more.

Nowadays, there is a great demand for increasing the strength and corrosion resistance of magnesium alloys for their wider use in machine engineering, oil industry, and medicine. This paper is devoted to a study on the effects of the combined process of reduction and equal channel angular pressing, as well as the subsequent ultrasonic irradiation on the structure, strength, and corrosion properties of the Mg-Al-Zn alloy. Deformation processing results in an increase of the strength up to 280 ± 10 MPa. A fine-grained structure is formed with a grain size of 10–20 µm and small recrystallized grains 1–2 µm in size. The corrosion resistance in the HCl medium falls down significantly. Action of ultrasound on the deformed specimen leads to an increased fraction of high-angle boundaries, in particular, the fractions of special, fully overlapping Σ13a boundaries and twin boundaries of Σ15b and Σ17a systems. Due to the ultrasonic treatment, the strength of the Mg-Al-Zn alloy increases up to 310 ± 5 MPa, while the corrosion resistance in HCl almost doubles. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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14 pages, 7651 KiB

Open AccessEditor’s ChoiceArticle

The Microstructure and Strength of UFG 6060 Alloy after Superplastic Deformation at a Lower Homologous Temperature

by Elena V. Bobruk, Pavel D. Dolzhenko, Maxim Yu. Murashkin, Ruslan Z. Valiev and Nariman A. Enikeev

Materials 2022, 15(19), 6983; https://doi.org/10.3390/ma15196983 - 08 Oct 2022

Cited by 6 | Viewed by 1468

Abstract

The paper reports on the features of low-temperature superplasticity of the heat-treatable aluminum Al-Mg-Si alloy in the ultrafine-grained state at temperatures below 0.5 times the melting point as well as on its post-deformation microstructure and tensile strength. We show that the refined microstructure [...] Read more.

The paper reports on the features of low-temperature superplasticity of the heat-treatable aluminum Al-Mg-Si alloy in the ultrafine-grained state at temperatures below 0.5 times the melting point as well as on its post-deformation microstructure and tensile strength. We show that the refined microstructure is retained after superplastic deformation in the range of deformation temperatures of 120–180 °C and strain rates of 5 × 10^–3 s^–1–10^–4 s^–1. In the absence of noticeable grain growth, the ultrafine-grained alloy maintains the strength up to 380 MPa after SP deformation, which considerably exceeds the value (250 MPa) for the alloy in the peak-aged coarse-grain state. This finding opens pathways to form high-strength articles of Al-Mg-Si alloys after superplastic forming. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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Review

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28 pages, 4976 KiB

Open AccessReview

Residual Stress Measurement Techniques for Metal Joints, Metallic Coatings and Components in the Railway Industry: A Review

by Olivia Kendall, Anna Paradowska, Ralph Abrahams, Mark Reid, Cong Qiu, Peter Mutton and Wenyi Yan

Materials 2023, 16(1), 232; https://doi.org/10.3390/ma16010232 - 27 Dec 2022

Cited by 3 | Viewed by 2938

Abstract

Manufacturing and maintenance procedures in the railway industry regularly implement welding and metal deposition operations to produce joints, coatings and repair structures. During these processes, residual stresses arise through the generation of heat affected zones and plastic deformation. This makes accurate measurements of [...] Read more.

Manufacturing and maintenance procedures in the railway industry regularly implement welding and metal deposition operations to produce joints, coatings and repair structures. During these processes, residual stresses arise through the generation of heat affected zones and plastic deformation. This makes accurate measurements of the internal stresses a critical aspect of manufacturing, monitoring, repair and model validation in the develop new metallic coating and joining technologies. Selection of an appropriate residual stress measurement method has many important factors including component size, resolution and the magnitude and location of internal stresses, often resulting in a combination of techniques required to obtain complete assessment of the stress state. This paper offers a review of residual stress measurement techniques for railway components including rail joints and coatings through comparison of destructive and non-destructive approaches, their measurement capabilities, benefits and limitations. A comprehensive discussion of different applications is provided with a summary of facilities available to both research and industry. Full article

(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)

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