Academic literature on the topic 'Β-Metastable'
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Journal articles on the topic "Β-Metastable":
1
Settefrati, Amico, Elisabeth Aeby-Gautier, Moukrane Dehmas, Guillaume Geandier, Benoît Appolaire, Sylvain Audion, and Jerôme Delfosse. "Precipitation in a near Beta Titanium Alloy on Ageing: Influence of Heating Rate and Chemical Composition of the Beta-Metastable Phase." Solid State Phenomena 172-174 (June 2011): 760–65. http://dx.doi.org/10.4028/www.scientific.net/ssp.172-174.760.
Abstract:
In the present study we focus on the precipitation processes during heating and ageing of β-metastable phase in the near β Ti-5553 alloy. Transformation processes have been studied using continuous high energy X-Ray Diffraction (XRD) and electrical resistivity for two different states of the β-metastable phase. Microstructures have been observed by electron microscopy. Different transformation sequences are highlighted depending on both heating rate and chemical composition of the β-metastable phase. At low temperatures and low heating rates, the hexagonal ωisophase is first formed as generally mentioned in the literature. Increasing the temperature, XRD evidences the formation of an orthorhombic phase (α’’), which evolves toward the hexagonal pseudo compact α phase. For higher heating rates or for richer composition in β-stabilizing elements of the β-metastable phase, ω phase may not form and α’’ forms directly and again transforms into α phase. A direct transformation from β-metastable to a phase is observed for the highest heating rate. The formation of the metastable ωisoand α’’ phases clearly influences the final morphology of α.
2
Niinomi, Mitsuo. "Enhancement of Mechanical Biocompatibility of Titanium Alloys by Deformation-Induced Transformation." Materials Science Forum 879 (November 2016): 125–30. http://dx.doi.org/10.4028/www.scientific.net/msf.879.125.
Abstract:
Metastable β-type titanium alloys are highly suitable for use as structural biomaterials applied to hard tissue, i.e., as cortical bone (hereafter, bone) replacing implants. However, their mechanical biocompatibitities, such as the Young’s modulus, strength and ductility balance, fatigue strength, resistance against fatigue crack propagation and fracture toughness, require improvenent for increased compatibility with bone. Through deformation, the metastable β-phase in a metastable β-type titanium alloy is transformed into various phases, such as α’ martensite, α” martensite, and ω-phases with exact phase depending by metastable β-phase stability. In addition, twinning is also induced by deformation. Deformation twinning effectively enhances the work hardening in the metastable β-type titanium alloy, leading to increased strength and ductility. This improvement is accompanied by with other deformation-induced transformations including the appearance of deformation-induced martensite and ω-phase transformation. The enhancement of the mechanical biocompatibility of various materials using the abovementioned deformation-induced transformation is described in this paper, for both newly developed metastable β-type Ti-Mo and Ti-Cr alloys for biomedical applications.
3
Wong, Ka-Kin, Hsueh-Chuan Hsu, Shih-Ching Wu, and Wen-Fu Ho. "A Review: Design from Beta Titanium Alloys to Medium-Entropy Alloys for Biomedical Applications." Materials 16, no. 21 (November 5, 2023): 7046. http://dx.doi.org/10.3390/ma16217046.
Abstract:
β-Ti alloys have long been investigated and applied in the biomedical field due to their exceptional mechanical properties, ductility, and corrosion resistance. Metastable β-Ti alloys have garnered interest in the realm of biomaterials owing to their notably low elastic modulus. Nevertheless, the inherent correlation between a low elastic modulus and relatively reduced strength persists, even in the case of metastable β-Ti alloys. Enhancing the strength of alloys contributes to improving their fatigue resistance, thereby preventing an implant material from failure in clinical usage. Recently, a series of biomedical high-entropy and medium-entropy alloys, composed of biocompatible elements such as Ti, Zr, Nb, Ta, and Mo, have been developed. Leveraging the contributions of the four core effects of high-entropy alloys, both biomedical high-entropy and medium-entropy alloys exhibit excellent mechanical strength, corrosion resistance, and biocompatibility, albeit accompanied by an elevated elastic modulus. To satisfy the demands of biomedical implants, researchers have sought to synthesize the strengths of high-entropy alloys and metastable β-Ti alloys, culminating in the development of metastable high-entropy/medium-entropy alloys that manifest both high strength and a low elastic modulus. Consequently, the design principles for new-generation biomedical medium-entropy alloys and conventional metastable β-Ti alloys can be converged. This review focuses on the design from β-Ti alloys to the novel metastable medium-entropy alloys for biomedical applications.
4
Yin, Jin Gou, Gang Chen, Shao Yang Zhao, Ping Tan, Zheng Feng Li, Jian Wang, and Hui Ping Tang. "Titanium-Tantalum Alloy Powder Produced by the Plasma Rotating Electrode Process (PREP)." Key Engineering Materials 770 (May 2018): 18–22. http://dx.doi.org/10.4028/www.scientific.net/kem.770.18.
Abstract:
Microstructure of Ti-28Ta powders produced by plasma rotating electrode process (PREP) was investigated by using scanning electron microscopy (SEM), optical microscopy (OM), and transmission electronic microscopy (TEM). Phase constituent of the PREP Ti-28Ta powders was analyzed by X-ray diffraction (XRD). It was found that microstructure of the PREP Ti-28Ta powders was dependent on the powder particle sizes. Predominant martensitic α”, some metastable β and trace athermal ω phases were observed in the powders with the small diameter. While, phase constituent of the PREP Ti-28Ta powders with the large particle size was predominant metastable β, some martensitic α” and trace athermal ω. With the reduction of the powder particle size, the amount of martensitic α” increased and the metastable β decreased. The martensitic α” was formed preferentially on the metastable β grain boundaries of the PREP Ti-28Ta powders. The increase of α” phase and decrease of β with reduction of the powder particle size is attributed to the increase of the volume of the grain boundaries due to the grain refinement.
5
Prima, Frédéric, Philippe Vermaut, I. Thibon, D. Ansel, Jean Debuigne, and Thierry Gloriant. "Nanostructured Metastable β-Titanium Based Alloy." Journal of Metastable and Nanocrystalline Materials 13 (January 2002): 307–14. http://dx.doi.org/10.4028/www.scientific.net/jmnm.13.307.
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Prima, Frédéric, Philippe Vermaut, I. Thibon, D. Ansel, Jean Debuigne, and Thierry Gloriant. "Nanostructured Metastable β-Titanium Based Alloy." Materials Science Forum 386-388 (January 2002): 307–14. http://dx.doi.org/10.4028/www.scientific.net/msf.386-388.307.
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Gialanella, S., and L. Lutterotti. "Metastable structures in α–β′ brass." Journal of Alloys and Compounds 317-318 (April 2001): 479–84. http://dx.doi.org/10.1016/s0925-8388(00)01374-8.
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Dobromyslov, A. V. "Phase Transformation in Binary Titanium-Base Alloys with Metals of the I, IV−VIII Groups." Materials Science Forum 546-549 (May 2007): 1349–54. http://dx.doi.org/10.4028/www.scientific.net/msf.546-549.1349.
Abstract:
Martensitic β→α′(α″) transformation, β→ω transformation and eutectoid decomposition in a series of Ti-base alloys with d transition metals of Groups I, IV-VIII have been investigated using the techniques of X-ray diffraction, optical and transmission electron microscopy. Phase and structural information is given on the non-equilibrium and metastable modifications occurring in these alloys after quenching from high-temperature β-field and aging. The conditions of the orthorhombic α″-phase, ω-phase and metastable β-phase formation in binary titanium–base alloys with d-metals of V-VIII groups were investigated. It was established that the position of the alloying metal in the Periodic Table defines the presence or absence of the α″-phase in the alloy after quenching and the minimum concentration of the alloying metal necessary for formation of the α″-phase, ω-phase and metastable β-phase.
9
Bovier, Anton, Frank den Hollander, and Saeda Marello. "Metastability for Glauber Dynamics on the Complete Graph with Coupling Disorder." Communications in Mathematical Physics 392, no. 1 (March 17, 2022): 307–45. http://dx.doi.org/10.1007/s00220-022-04351-8.
Abstract:
AbstractConsider the complete graph on n vertices. To each vertex assign an Ising spin that can take the values $$-1$$ - 1 or $$+1$$ + 1 . Each spin $$i \in [n]=\{1,2,\dots , n\}$$ i ∈ [ n ] = { 1 , 2 , ⋯ , n } interacts with a magnetic field $$h \in [0,\infty )$$ h ∈ [ 0 , ∞ ) , while each pair of spins $$i,j \in [n]$$ i , j ∈ [ n ] interact with each other at coupling strength $$n^{-1} J(i)J(j)$$ n - 1 J ( i ) J ( j ) , where $$J=(J(i))_{i \in [n]}$$ J = ( J ( i ) ) i ∈ [ n ] are i.i.d. non-negative random variables drawn from a probability distribution with finite support. Spins flip according to a Metropolis dynamics at inverse temperature $$\beta \in (0,\infty )$$ β ∈ ( 0 , ∞ ) . We show that there are critical thresholds $$\beta _c$$ β c and $$h_c(\beta )$$ h c ( β ) such that, in the limit as $$n\rightarrow \infty $$ n → ∞ , the system exhibits metastable behaviour if and only if $$\beta \in (\beta _c, \infty )$$ β ∈ ( β c , ∞ ) and $$h \in [0,h_c(\beta ))$$ h ∈ [ 0 , h c ( β ) ) . Our main result is a sharp asymptotics, up to a multiplicative error $$1+o_n(1)$$ 1 + o n ( 1 ) , of the average crossover time from any metastable state to the set of states with lower free energy. We use standard techniques of the potential-theoretic approach to metastability. The leading order term in the asymptotics does not depend on the realisation of J, while the correction terms do. The leading order of the correction term is $$\sqrt{n}$$ n times a centred Gaussian random variable with a complicated variance depending on $$\beta ,h$$ β , h , on the law of J and on the metastable state. The critical thresholds $$\beta _c$$ β c and $$h_c(\beta )$$ h c ( β ) depend on the law of J, and so does the number of metastable states. We derive an explicit formula for $$\beta _c$$ β c and identify some properties of $$\beta \mapsto h_c(\beta )$$ β ↦ h c ( β ) . Interestingly, the latter is not necessarily monotone, meaning that the metastable crossover may be re-entrant.
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Liao, Guang Yue, Shun Guo, Zhen Zhen Bao, and Xin Qing Zhao. "β Stability and Mechanical Behavior of Metastable β Type TiNb Based Alloys." Materials Science Forum 747-748 (February 2013): 941–46. http://dx.doi.org/10.4028/www.scientific.net/msf.747-748.941.
Abstract:
Metastable β type TiNb based alloys of Ti-35Nb, Ti-35Nb-4Sn and Ti-42Nb-4Sn (wt. %) with different stability were prepared and thermo-mechanical treatment was carried out to investigate their microstructural evolution and mechanical properties. It was found that although the TiNb based alloy with lower stability performs lower strength in its solution state due to the stress induced martensitic transformation, they could be strengthened significantly by severe cold rolling followed by aging, remaining a relative low elastic modulus. X-ray diffraction, transmission electron microscopy and mechanical test were conducted to characterize the microstructural evolution and mechanical behavior of the metastable β type TiNb based alloys with different β stability. The strengthening mechanism was discussed on the basis of the cold deformation and martensitic transformation.
Dissertations / Theses on the topic "Β-Metastable":
1
Fan, Jiangkun. "Microstructural study of the β→α phase transformation induced by thermo-mechanical treatments in metastable β Ti-5553 alloy." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0144/document.
Abstract:
Les alliages de titane β métastables sont des matériaux de structure essentiels pour les applications aéronautiques de part leurs très bonnes propriétés mécaniques. En effet, ils présentent une résistance spécifique élevée, une bonne ductilité et forgeabilité et une excellente réponse aux traitements thermiques. Toutefois, il existe encore aujourd'hui à leur sujet des controverses et des questions ouvertes et ce, malgré les efforts pour comprendre les mécanismes d'évolution microstructurale au cours de traitements thermo-mécaniques et pour déterminer les phases en présence et leur contribution aux les propriétés mécaniques résultantes. Ce travail de thèse a pour objectif de déterminer la nature de la phase β et de caractériser la transformation β→α à haute et basse températures par des caractérisations fines en microscopie électronique à balayage et à transmission couplées à des mesures d'orientations cristallographiques et de composition chimique. L'alliage étudié est un Ti-5553 avec une microstructure initiale 100% β obtenue par mise en solution et trempe. Il a été démontré expérimentalement que la structure de la phase β métastable n'est pas purement cubique centrée. Les points de la phase β dans les clichés de diffraction présentent un allongement (streaking) et des points supplémentaires sont visibles aux positions de diffraction 1/2, 1/3 et 2/3. Par ailleurs, les images MET ont un aspect en moiré. A partir de ces résultats et de calculs crystallographiques, il a été prouvé que des déplacements atomiques sur les plans {110}β et {112}β forment une structure intermédiaire entre celle de la phase β parente et celles des phases α et ω, prouvant que la phase β a intrinsèquement initié une transformation. L'étude de la précipitation au cours du procédé thermomécanique dans le domaine α+β a révélé que des précipités α discontinus, équiaxes ou légèrement allongés (1~2μm) se forment aux joints β de forte et de faible désorientation mais rarement au coeur des grains β produisant ainsi une microstructure en "collier". La relation d'orientation de Burgers (ROB) entre les phases α et β est progressivement détruite par la déformation. L'écart à la ROB est plus marqué pour les précipités α qui se forment au joint de grains qu'à l'intérieur des grains. L'écart à la ROB augmente aussi avec la déformation, mais diminue avec la vitesse de déformation. Au cours des déformations en bas du domaine α+β, les précipités α ont une morphologie qui dépend de leur position. Au coeur des bandes de glissement, les grains α/β sont équiaxes et ne respectent pas la ROB. Entre les bandes de glissement, la microstructure est lamellaire où les phases α/β alternent et respectent la ROB. Dans ce dernier cas, une forte sélection de variantes a été observée: Seuls les deux ou trois variants favorisant l'accommodation de la déformation se sont formés. A titre de comparaison, dans l'état non déformé, les 12 précipités sont présents. La transformation β→α est retardée en cours de compression à haute température. Ceci est attribué à une compétition entre adoucissement et transformation de phase. Au contraire, celle-ci est favorisée au cours de la compression à plus basse température du fait que les défauts cristallins induits par la déformation jouent le role de sites de germination et que la croissance des précipités soit accéléré alors que l'adoucissement soit ralenti. Dans le Ti-5553, le mécanisme de déformation dominant est le glissement des dislocations. Dans les déformations en bas du domaine α+β, du glissement simple ou multiple avec deux ou trois systèmes de glissement activés. L'identification de ces systèmes a pu être effectuée par des analyses de traces. Cette thèse a résolu la nature de la phase β métastable et constitue un travail de référence pour l'étude de la transformation β→α au cours de traitement thermomécaniqueMetastable β titanium alloys are important structural materials for aeronautical applications due to their high strength to density ratio, good ductility and workability and excellent hardenability. Despite the efforts in resolving the complex microstructural evolution related to thermomechanical processes and in gaining knowledge on the produced phases and their contribution to the resultant mechanical properties, there are still some controversial and unresolved issues. The aim of the present PhD work is to determine precisely the metastable nature of β phase and to characterize finely the characteristics of the β→α transformation during high and low temperature thermomechanical treatments. Investigations were performed on a Ti-5553 alloy with the single β phase initial microstructure obtained by solution treatment followed by quenching using scanning and transmission electron microscopy (SEM/TEM) coupled to crystallographic orientation measurements and chemical analyses. It was demonstrated experimentally that the structure of the β phase in the metastable titanium alloy is not “pure” body centered cubic. Diffraction diagrams presents streaking of the β diffraction spots and additional spots at the 1/2, the 1/3 and 2/3 diffraction positions. Also, striations are observed in TEM images. From this experimental evidence and crystallographic calculations, it was proved that atomic displacements on the {110}β and {112}β planes formed a structure between that of the parent β phase and that of the α or ω phase, demonstrating pre-phase transformation tendency. The study of the precipitation during thermomechanical processing at higher temperature in the α+β region revealed that discontinuous equiaxed or short rod shaped α precipitates (1~2μm) mainly form on the high angle and low angle β grain boundaries but seldom in β grain interiors, forming the “necklace” microstructure. The Burgers orientation relationship (BOR) between the α and β phases is destroyed gradually by the deformation. The BOR deviation of grain boundary α is larger than that of intragranular α. The deviation from the BOR increases both with the increasing strain and decreasing strain rate. During the deformation at the lower temperature in the α+β region, the α precipitates exhibit different morphologies: such as lamellar α, equiaxed α and irregular α depending on their localization. Within the slip bands, equiaxed α/β grains which do not respect the BOR are present. However, between the bands, lamellar α and β phases maintaining the BOR are distributed alternately. In that last case a strong variant selection is observed as only the two or three variants that form are those which can accommodate the macroscopic deformation. Comparatively, in absence of compression all 12 variants are formed. The β→α phase transformation is retarded during the hot compression at higher temperature region, which is attributed to the competition between softening and phase transformation. On the contrary, it is promoted during compression at lower temperature region due to the more inducted deformation defects acting as α phase nucleation sites and due to accelerating growth of α precipitates and retarded softening. Dislocation slip is the leading deformation mechanism for the Ti-5553 alloy. Under the lower temperature deformation condition, single or multiple-slip bands with two or three different activated slip systems would form during the hot deformation process. Identification of these slip systems have been done by trace analysis. These results provide new insights into the structural nature of β metastable phase and valuable reference for β→α phase transformation during thermo-mechanical treatment in metastable β titanium alloys
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Hua, Ke. "Displacive characteristics of β to α phase transformation and its impact on hot deformation behavior in Ti-7333 metastable β titanium alloy." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0213.
Abstract:
Une étude approfondie a été menée sur l’alliage Ti-7333 en termes de transformation de phase β en α. Il a été montré que la transformation de la structure est réalisée par une contraction dans<1"1" ̅"2" ̅>β, un allongement dans <"1" ̅1"1" ̅>β et <110>β, et un cisaillement sur le système de glissement{1"1" ̅"2" ̅}β<"1" ̅1"1" ̅>β. Chaque précipité α est composé de deux types de domaines α de taille nanométrique. L'un est situé sur la face large du précipité α majeur (interface α), l'autre traverse le α majeur (α pénétrant). La nucléation de cet α est induite par la contrainte importante de cisaillement générée par la formation du α majeur. Le α pénétrant n'obéit pas au BOR avec la matrice β mais. La nucléation de cet α est induite par la plus grande contrainte normale générée par la formation de la plaque α principale. La sélection des variantes α lors de la déformation à chaud à 700 °C s'effectue en fonction de la perfection cristalline locale des grains β. Dans les grains β légèrement déformés, 2 variantes de BOR liées. Les variantes sélectionnées apportent une contribution maximale à la déformation macroscopique et subissent la contrainte de cisaillement résolue maximale de la charge externe résolue sur leurs systèmes de transformation {1"1" ̅"2" ̅}β<"1" ̅1"1" ̅>β. Dans les grains β fortement déformés occupés principalement par des bandes de glissement, 2 à 4 variantes de BOR sont sélectionnées. Le critère de sélection est toujours respecté mais avec une restriction de la déformation locale. Le comportement en déformation lors de la compression à 700 °C présente trois stades contraintes-déformations caractéristiques : un stade linéaire (stade I), un stade d’écoulement discontinu (stade II) et un stade stable (stade III). À la fin du stade I, plus de 90% des joints de grains β sont occupés par des joints de grains α (αGB). Le rendement discontinu du stade II provient de la fragmentation de αGB et de la formation intensive de dislocations mobiles près des joints de grains β. L'état d'équilibre du stade III résulte de deux modes de déformation. Pour ceux dont l'orientation d'activation est favorable pour leurs systèmes {110}β<1"1" ̅1>β par rapport à la charge de compression, la déformation est réalisée par le glissement de dislocation et par la formation de bandes de glissement; alors que pour ceux avec leur {1"1" ̅"2" ̅}β<"1" ̅1"1" ̅>β systèmes - le système de transformation de β à α - dans des orientations favorables, la déformation est obtenue par formation intensive de précipités α intragranulairesA thorough investigation has been conducted on the Ti-7333 alloy in terms of the β to α phase transformation. It was revealed that the structure transformation is realized by a contraction in the <1"1" ̅"2" ̅>β, an elongation in the <"1" ̅1"1" ̅>β and <110>β, and a shear on the {1"1" ̅"2" ̅}β<"1" ̅1"1" ̅>β slip system. Each α precipitate is composed of two kinds of nano-sized α domains. One is situated on the broad face of the major α precipitate (named interface α), and the other goes through the major α (termed penetrating α). The nucleation of such α is induced by the large shear strain generated by the formation of the major α. The penetrating α does not obey the BOR with the β matrix. The nucleation of such α is induced by the largest normal strain generated by the formation of the main α plate. The selection of the α variants during hot deformation at 700°C happens with dependence on the local crystal perfection of the β grains. In the slightly deformed β grains, 2 BOR variants are formed ‘cross-shaped’ clusters. The selected variants make maximum contribution to the macroscopic deformation and receive the maximum resolved shear stress from the external load resolved on their {1"1" ̅"2" ̅}β<"1" ̅1"1" ̅>β systems for transformation. In the heavily deformed β grains occupied mainly by dislocation slip, 2 to 4 BOR variants are selected in smaller numbers. The selection criterion is still obeyed but with restriction from the local deformation. The deformation behavior during 700°C compression presents three characteristic stress-strain stages: a linear stage (Stage I), a discontinuous yielding (Stage II) and a steady-state (Stage III). At the end of Stage I, more than 90% of the β boundaries are occupied by grain boundaries α (αGB). The discontinuous yielding of Stage II originated from the fragmentation of the αGB and the intensive formation of mobile dislocations near the β grain boundary areas. The steady-state of Stage III arises from two orientation dependent deformation modes of the β grains. For those in favorable activation orientation for their {110}β<1"1" ̅1>β systems with respect to the external compressive load, the deformation is realized by the dislocation slip and by the formation of slip bands; whereas for those with their {1"1" ̅"2" ̅}β<"1" ̅1"1" ̅>β systems - the system for β to α transformation - in favorable orientations, the deformation is achieved by intensive formation of intragranular α precipitates
3
Zhang, Jinyong. "Mechanical Behavior and Microstructural Evolution in Metastable β Ti-Mo Based Alloys with TRIP and TWIP Effects." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066313/document.
Abstract:
Dans ce travail, basé sur une approche semi empirique de conception d’alliages de titane à propriétés mécaniques contrôlées, un alliage modèle binaire Ti-12Mo (% massique) et des alliages ternaires sur la base du système Ti-Mo ont été élaborés, combinant des effets TRIP et TWIP lors de la déformation. (TRIP – Transformation Induced Plasticity : plasticité induite par transformation ; TWIP – Twinning Induced Plasticity : plasticité induite par maclage).Les résultats des essais mécaniques montrent que ces alliages présentent une haute résistance mécanique (1000-1200 MPa), une grande plasticité (entre 0,3 et 0,4) et un écrouissage amélioré grâce aux effets simultanés TRIP/TWIP. Différentes techniques de caractérisation telles que la diffraction de rayons X conventionnelle (XRD), la diffraction in-situ sur Synchrotron (SXRD), la diffraction d’électrons rétro-diffusés (EBSD), les mesures de résistivité électrique (ERM), la microscopie électronique en transmission (TEM) et les mesures et traitements automatiques des orientations cristallographiques associées (ACOM/TEM), ont été mis en œuvre pour étudier les mécanismes de déformation, les transformations de phases et l’évolution microstructurale.Différents mécanismes de déformation, tels que le maclage mécanique {332}<113> et la transformation martensitique induite sous contrainte α˝ ont été identifiés à l’issue des essais mécaniques, permettant d’expliquer l’excellente combinaison de propriétés mécaniques obtenue. L’optimisation microstructurale de ces alliages a été conduite à partir de recuits basses températures dans le domaine de précipitation de la phase ω avec pour objectif d’améliorer les propriétés mécaniques afin de contrôler la formation de la phase ω sans modifier de manière excessive la composition chimique de la matrice β, et conserver les effets combinés TRIP/TWIPIn this work, based on combination of the ‘d-electron alloy design method’ and controlling of electron/atom ratio (e/a), a model of binary Ti-12Mo (wt. %) and ternary Ti-Mo based alloys were designed, induced combined TRIP and TWIP effects (TRIP for Transformation Induced Plasticity and TWIP for Twinning Induced Plasticity). The tensile results show that so-designed alloys exhibit true stress-strain values at uniform plastic deformation, of about 1000-1200MPa and between 0.3 and 0.4 of strain, with a large strain-hardening rate. Several characterization techniques, such as conventional X-ray diffraction (XRD), In-situ Synchrotron X-ray diffraction (SXRD), electron backscatter diffraction (EBSD), electrical resistivity measurements (ERM), transmission electron microscopy (TEM) and automatic crystal orientation measurements (ACOM) TEM, were carried out to to investigate the deformation mechanisms and microstructure evolution sequence. Various deformation mechanisms, i.e. {332}<113> mechanical twinning, deformation induced ω phase and stress-induced α’’ martensite, were identified after mechanical testing, resulting in a combination of high strength, large ductility and improved strain-hardening rate. Furthermore, low temperature aging (LTA) treatments were performed on the Ti-12Mo alloy to improve the mechanical property through controlling the ω phase transformation without excessive modification of β matrix chemical composition, keeping the possibility for combined TRIP and TWIP effects to occur. The influence of LTA treatment on the mechanical behavior and microstructural evolution of Ti-12Mo alloy was discussed in detail
4
Hendrickson, Mandana. "The Role of Misfit Strain and Oxygen Content on Formation and Evolution of Omega Precipitate in Metastable Beta-titanium Alloys." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc955080/.
Abstract:
β-Ti alloys are widely used in airframe and biomedical applications due to their high ductility, high hardenability, and low elastic modulus. The phase transformations in β-Ti alloys are rather complex due to formation of metastable phases during various thermo-mechanical treatments. One such critical metastable phase, the hexagonal omega (ω) phase, can form in β-Ti alloys under quenching from the high temperature β phase and/or isothermal aging at intermediate temperature. Despite a substantial amount of reported works on the ω phase, there are several critical issues related to the ω formation need to be resolved, e.g. role of alloying elements and oxygen content. Therefore, this dissertation has attempted to provide insights into ω transformation in low misfit (Ti-Mo) and high misfit (Ti-V) binary systems as well as multicomponent (Ti-Nb-Zr-Ta) alloys.
The evolution of ω structure, morphology and composition from the early stage (β-solution+quenched) to later stages after prolonged aging are systematically investigated by coupling transmission electron microscopy (TEM), atom probe tomography (APT) and high-energy synchrotron X-ray diffraction techniques. The influence of aging temperature and duration on characteristic of ω phase in Ti-Mo, and Ti-V alloys is addressed in details. It is found that compositional changes during aging can alter the structure, size and morphology of ω precipitates. In low misfit alloys, the ellipsoidal morphology of ω phase was retained during isothermal aging, while in high misfit alloys it changed from ellipsoidal to cuboidal morphology after prolonged aging. Secondly, ω transformation in biomedical Ti-Nb-Zr-Ta alloy is probed in which the micro-hardness was sensitive to microstructural changes. Furthermore, the evolution of oxygen concentration in ω precipitates during various aging conditions in binary Ti-Mo and Ti-V alloys are reported. It has been accepted that interstitial elements such as oxygen can largely alter mechanical behavior and the microstructure of Ti-alloys. Recently, oxygen is intentionally added to some biomedical alloys to improve their performances. However, a careful understanding of the effect of oxygen on ω phase transformation is still lacking in the literature. In this work, the role of oxygen on ω phase formation in biomedical TNTZ alloys is investigated. Although it is traditionally accepted that oxygen suppresses ω transformation, our observations revealed contradictory results during isothermal aging of TNZT alloys. The results of our investigations provide a novel insight into understanding the effect of interstitial elements on metastable phase transformation in β-Ti alloys. It is concluded that depending upon the nature of alloying elements and/or the applied thermo-mechanical treatments, oxygen may play a different role in ω transformations.
5
Lai, Minjie Verfasser], Dierk [Akademischer Betreuer] Raabe, and Robert [Akademischer Betreuer] [Svendsen. "Experimental-theoretical study of the interplay between deformation mechanisms and secondary phases in metastable β titanium alloys / Minjie Lai ; Dierk Raabe, Bob Svendsen." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1158498632/34.
6
Lai, Minjie [Verfasser], Dierk Akademischer Betreuer] Raabe, and Robert [Akademischer Betreuer] [Svendsen. "Experimental-theoretical study of the interplay between deformation mechanisms and secondary phases in metastable β titanium alloys / Minjie Lai ; Dierk Raabe, Bob Svendsen." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1158498632/34.
7
Varenne, Chloé. "Etude d'un alliage de titane β "transformable par déformation" : lien entre propriétés mécaniques, microstructures de déformation et mécanismes de rupture." Thesis, Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLM030.
Abstract:
Afin de pallier la ductilité et le taux d’écrouissage limités des alliages de titane, une nouvelle famille a été développée : les alliages de titane β transformables par déformation. Leurs mécanismes de déformation mettent en jeu la plasticité induite par transformation de phase (effet TRIP) et par maclage (effet TWIP), et sont largement étudiés depuis une dizaine d’années. Au contraire, la compréhension des mécanismes de rupture de ces alliages est faiblement documentée alors qu’elle reste essentielle afin de gagner en maturité dans leur développement. Ce projet avait pour but d’étudier en détail le comportement mécanique sous sollicitations variées d’un alliage β TWIP : Ti-8,5Cr-1,5Sn, à gros grains, afin de décorréler les échelles d’observation. Dans un premier temps, une méthodologie d’étude systématique de cette famille d’alliages a été mise au point. Nous avons statué sur les conditions de traitement thermique (épaisseur de trempe) et de réalisation des essais (géométrie d’éprouvette, type de chargement) et sélectionné les essais les plus pertinents pour une étude complète du comportement mécanique d’un alliage TRIP/TWIP. Cette méthodologie a ensuite été validée sur un alliage Ti-8,5Cr-1,5Sn tout d’abord à température ambiante, puis à température négative. Le comportement mécanique a été évalué dans une large gamme de conditions : traction uniaxiale, traction sur éprouvette entaillée, résilience, ténacité. Les contributions respectives de l’amorçage et de la propagation de fissure ont notamment été déterminées. Une corrélation, multi-échelles (optique, MEB, MET), a permis de mettre en évidence une rupture par localisation de la déformation, sans endommagement, fortement corrélée aux mécanismes de déformation plastique et indépendante des variations de vitesse de sollicitation et de triaxialité des contraintes. A température négative, l’absence de transition ductile-fragile a été mise en évidence sur les mécanismes de rupture, tout comme la conservation de la phénoménologie observée à l’ambiante (pas d’effet TRIP déclenché). La rupture, alors à basse énergie, met toujours en jeu un mécanisme ductile à cupules. La rupture reste régie par la localisation de la déformation, qui se déclenche d’autant plus tôt que la température d’essai est basse. Cette étude nouvelle et complète a permis d’approfondir la compréhension de la rupture d'un alliage TRIP/TWIP et fournit une base de données solide pour de futures études d’alliages de la même familleIn order to tackle the lack of ductility and work-hardening of titanium alloys, a new family is being developed, namely, strain-transformable β titanium alloys. The deformation mechanisms involve transformation induced plasticity (TRIP effect) and twinning induced plasticity (TWIP effect). They have been widely studied over the last ten years. On the otherhand, the understanding of fracture mechanisms of TRIP/TWIP titanium alloys still remains poorly documented although this is a key to improve the development of these alloys. Therefore, this project is an in-depth study of the mechanical behavior of a Ti-8.5Cr-1.5Sn β TWIP alloy, under various loading conditions. The coarse microstructure of the alloy was used to investigate deformation and fracture on a grain-by-grain basis. First, a methodology for the systematic study of this family of alloys has been developed. We selected the most relevant tests for a complete study of the mechanical behavior of a TRIP/TWIP alloy by investigating heat treatment conditions (quenching thickness) and mechanical testing conditions (specimen geometry, loading mode). Then,this methodology was validated on the Ti-8.5Cr-1.5Sn alloy first at room temperature, then at subzero temperatures, in order to get closer to the Ms point. The mechanical behavior was evaluated under a wide range of conditions giving access to tensile strength, impact toughness, and fracture toughness. The respective contributions of crack initiation and crack propagation were determined. A multi-scale correlation (optical, SEM, TEM) highlighted fracture by localized plastic flow, without damage development, strongly correlated with the plastic deformation mechanisms and independent of variations in strain rate and stress triaxiality. At subzero temperatures, the absence of ductile-to-brittle transition was demonstrated on the failure mechanisms, as was thepreservation of the phenomenology observed at room temperature (no triggered TRIP effect). Low energy fracture encountered at lower temperatures still involved a ductile dimple mechanism. It remained governed by localized plastic flow, which is triggered all the earlier the lower the test temperature. This new and comprehensive study has improved the understanding of fracture mechanisms of a TRIP/TWIP alloy and provides a solid database for further studies of this family of alloys
8
Goetz, Morgan. "Contribution à l’étude des mécanismes mis en jeu au cours de la transformation β → α dans des alliages de titane à vocations aéronautiques." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0287.
Abstract:
Le premier objectif de la thèse est d’étudier l’influence de la teneur nominale en Al, Zr et Hf sur les évolutions microstructurales d’un alliage bêta-métastable Ti-5Al-5Mo-5V-3Cr au refroidissement (étagé et continu) depuis le domaine bêta. Trois alliages bêta-métastable de compositions différentes sont ainsi considérés : les alliages Ti-5553 (référence), Natis 1 et Natis 2. Nous utilisons des techniques, d’une part pour suivre en temps réel les séquences et cinétiques globales de transformations de phases (résistivité électrique, DRXHE), et d’autre part pour caractériser post mortem les microstructures héritées de ces transformations (DRXHE, MEB, MET, analyse d’images, macro-dureté). Des microstructures grossières sont également fabriquées dans le cas des alliages Natis en vue de préciser le rôle des éléments Zr et Hf. La complémentarité des moyens mis en œuvre permet in fine d’établir les domaines en temps et température d’apparition des phases stables (alpha, alpha2, bêta) et métastables (alpha’’, oméga) synthétisés sur les diagrammes TTT et TRC. Il s’avère ainsi que les cinétiques globales de transformations de phases et les microstructures résultantes sont fortement dépendantes des conditions thermiques, mais ne varient pas sensiblement selon l’alliage considéré. Cela résulte de la faible différence de composition nominale entre les alliages et du caractère chimiquement neutre de Zr et Hf. D’autre part, l’analyse des cinétiques en conditions isothermes par un modèle JMAK permet de prédire l’évolution des différentes phases et morphologies apparaissant au refroidissement dans les trois alliages.Le second objectif de la thèse est de déterminer la nature des transformations bêta => alpha et bêta => alpha’’ dans l’alliage Ti-5553. À cet effet, des microstructures sont générées pour différentes conditions de transformations isothermes et les évolutions des caractéristiques microstructurales et chimiques sont étudiées par une approche quantitative et multi-échelle (DRXHE, MEB, MET, STEM-EDX, SAT). Ces analyses aux résultats concordants montrent une partition effective des éléments d’alliage lors de la transformation bêta => alpha à haute température (> 650°C) : la composition des phases alpha et bêta s’avère concorder avec celle calculée par Thermo-Calc®. Pour des températures intermédiaires (600°C), la composition de la phase alpha est hors équilibre, puis évolue au cours du temps pour tendre vers celle d’équilibre. Pour analyser cette évolution, nous utilisons un modèle de champ de phase en considérant un alliage ternaire Ti-Mo-V. La confrontation calculs/expériences suggère que la croissance de la phase alpha procède selon un mode mixte, associant diffusion en volume et processus interfacial. Enfin, pour les basses températures (325°C), la transformation bêta => alpha’’ s’accompagne aux premiers instants d’une diffusion à courte distance des éléments d’alliages conduisant à une phase bêta chimiquement hétérogène. La partition des éléments d’alliage entre alpha’’ et bêta est davantage marquée pour des temps de maintien isotherme prolongésThe first goal of the work is to investigate the influence of the nominal content in Al, Zr and Hf on the microstructural evolutions of beta-metastable Ti-5Al-5Mo-5V-3Cr alloy during cooling (stepped and continuous) from the beta domain. Three beta-metastable alloys with different compositions are thus considered: Ti-5553 (reference), Natis 1 and Natis 2. We have monitored in situ the overall sequences and kinetics of phase transformations (electrical resistivity, HEXRD) and characterized post mortem the microstructures formed during these transformations (HEXRD, SEM, TEM, image analysis, macro-hardness). Coarse microstructures are also generated in the case of Natis alloys to unravel the role of Zr and Hf. Using all these techniques, we have been able to establish the time and temperature ranges where the stable (alpha, alpha2, beta) and metastable (alpha’’, omega) phases appear, to build TTT and CCT diagrams. It turns out that the overall kinetics of phase transformations and the resulting microstructures are highly dependent on thermal conditions but do not vary significantly between the three alloys. This results from the small difference in nominal composition between the alloys as well as from the neutral role of Zr and Hf elements in terms of partitioning. Based on the analysis of the isothermal kinetics using JMAK model, we have been able to predict the evolution of the phases and morphologies during cooling for the three alloys.The second aim of the work is to investigate the mechanisms involved in the beta => alpha and beta => alpha’’ transformations in Ti-5553 alloy. For this purpose, microstructures are generated during different isothermal treatments and the evolution of the microstructural features and compositions are determined following a quantitative multi-scale approach (HEXRD, SEM, TEM, STEM-EDX, APT). This investigation shows that there is a fast effective partition of the alloying elements during the beta => alpha transformation at high temperature (> 650°C): the compositions of alpha and beta do not vary significantly with holding time and are close to the predictions by Thermo-Calc®. At intermediate temperatures (600°C), alpha displays an initial non-equilibrium composition that evolves slowly towards equilibrium. This evolution has been analyzed using a phase field model, considering a ternary Ti-Mo-V alloy. The calculations have been shown to agree with the measurements if alpha growth is mixed mode, i.e. controlled by bulk diffusion and interfacial process. Finally, at low temperatures (325°C), beta => alpha’’ transformation is accompanied by short distance diffusion resulting in a slight partition between alpha’’ and beta that increases with the treatment duration
9
Chini, Maria Rita. "Analyse des hétérogénéités de microstructure et de microtexture héritées par transformation de phase β→α dans des pièces massives en alliage Ti-10V-2Fe-3Al : influence sur la dispersion des propriétés mécaniques." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0149.
Abstract:
Les alliages de titane β-métastables comme le Ti-10V-2Fe-3Al se substituent progressivement aux alliages α/β dans les applications aéronautiques du fait de leur résistance spécifique améliorée. Leurs microstructures d'emploi sont cependant complexes et multi-échelles, constituées d'une matrice β (de grains millimétriques) partiellement transformée en nodules primaires αp (micrométriques) et en lamelles secondaires αs (sub-micrométriques). Les propriétés finales peuvent être très sensibles aux variations locales de microstructures et sont souvent non maîtrisées lors du forgeage de pièces massives. De plus la matrice β qui représente ~40% du volume et qui a un comportement élastique et plastique fortement anisotrope, comme la phase α, complique la compréhension des mécanismes de déformation en jeu. Le premier objectif de cette thèse est de mettre en œuvre des techniques de caractérisation multi-échelles (la diffraction des neutrons, l'imagerie électronique couplée à l'analyse d'image et l'EBSD, la reconstruction des microtextures de haute température β/αp) pour analyser efficacement la microstructure/texture des constituants β/αp/αs et caractériser leurs hétérogénéités au sein de demi-produits et de pièces obtenues par matriçage. Les résultats permettent d'analyser la fragmentation des grains β en sous-grains, les macrozones αp, le maintien de relation d'orientation entre β/αp et l'organisation des lamelles αs en colonies ou paniers tressés, en pointant les différences de taille de domaines révélés par la cristallographie et l'imagerie standard. Le second objectif est d'appliquer cette méthodologie à l'analyse de facies de rupture d'éprouvettes présentant un comportement singulier (en traction ou en fatigue) pour caractériser les configurations microstructurales à l'origine de l'amorçage de fissures. Cette analyse a principalement été réalisée par polissage manuel du faciès couplé à des acquisitions EBSD mais également en exploitant le potentiel de l'imagerie 3D par MEB-FIB (Focus Ion Beam) et la technique TKD (Transmission Kikuchi Diffraction) sur lame mince prélevée au niveau d'un site d'amorçage par FIB. Enfin, cette étude expérimentale a été complétée par une première approche en simulation micromécanique sur une microstructure modèle 100% β. L'objectif était d'évaluer l'influence de l’anisotropie élastique de la phase β sur la genèse de contraintes d'incompatibilités dans les régimes élastique et élasto-plastique. L'ensemble des résultats contribue à une meilleure compréhension des variations de propriétés mécaniques en lien avec la microstructure localeThe β-metastable titanium alloys such as Ti-10V-2Fe-3Al are gradually replacing α/β alloys in aeronautical applications thanks to their improved specific strength. However, their microstructures are complex and multi-scale, consisting of a β matrix (of millimetric grains) partially transformed into primary αp nodules (micrometric) and secondary αs lamellae (sub-micrometric). The final mechanical properties are very sensitive to local variations of the microstructure, which are not always fully controlled during forging of massive parts. Moreover, the β matrix, which represent 40% of the volume and whose elastic and plastic behavior is strongly anisotropic (like the α phase) complicates the understanding of the mechanisms of deformation. The first objective of this thesis was to efficiently characterize the microstructure/texture of the different constituents (β/αp/αs) and their heterogeneities within half-finished products and forged parts by using techniques of multi-scale characterization (neutron diffraction, electronic imaging coupled with image analysis and EBSD, reconstruction of high temperature microtextures β/αp). As a result the fragmentation of the β grains into subgrains, the αp macrozones, the destruction of the orientation relation between β/αp and the organization of the αs lamellae in colonies or basket weave was quantified and the differences in size of domains revealed by crystallography and by standard imaging were pointed out. The second objective is to apply this methodology to the analysis of fracture surfaces of samples exhibiting singular behavior (in tension or in fatigue) in order to characterize the microstructural configurations leading to early cracking. This analysis was mainly performed by manual polishing coupled with EBSD acquisitions but also by using 3D imaging by SEM-FIB (Focus Ion Beam) and TKD (Transmission Kikuchi Diffraction) technique on a thin foil FIB-extracted from the crack initiation site. Finally, this experimental study was completed by a micromechanical simulation on a 100% β model microstructure. The objective was to evaluate the influence of the elastic anisotropy of the β phase on the genesis of incompatibility stresses in the elastic and elasto-plastic regimes. The overall results contribute to a better understanding of the variations of mechanical properties related to the local microstructure
10
Chini, Maria Rita. "Analyse des hétérogénéités de microstructure et de microtexture héritées par transformation de phase β→α dans des pièces massives en alliage Ti-10V-2Fe-3Al : influence sur la dispersion des propriétés mécaniques." Electronic Thesis or Diss., Université de Lorraine, 2018. http://www.theses.fr/2018LORR0149.
Abstract:
Les alliages de titane β-métastables comme le Ti-10V-2Fe-3Al se substituent progressivement aux alliages α/β dans les applications aéronautiques du fait de leur résistance spécifique améliorée. Leurs microstructures d'emploi sont cependant complexes et multi-échelles, constituées d'une matrice β (de grains millimétriques) partiellement transformée en nodules primaires αp (micrométriques) et en lamelles secondaires αs (sub-micrométriques). Les propriétés finales peuvent être très sensibles aux variations locales de microstructures et sont souvent non maîtrisées lors du forgeage de pièces massives. De plus la matrice β qui représente ~40% du volume et qui a un comportement élastique et plastique fortement anisotrope, comme la phase α, complique la compréhension des mécanismes de déformation en jeu. Le premier objectif de cette thèse est de mettre en œuvre des techniques de caractérisation multi-échelles (la diffraction des neutrons, l'imagerie électronique couplée à l'analyse d'image et l'EBSD, la reconstruction des microtextures de haute température β/αp) pour analyser efficacement la microstructure/texture des constituants β/αp/αs et caractériser leurs hétérogénéités au sein de demi-produits et de pièces obtenues par matriçage. Les résultats permettent d'analyser la fragmentation des grains β en sous-grains, les macrozones αp, le maintien de relation d'orientation entre β/αp et l'organisation des lamelles αs en colonies ou paniers tressés, en pointant les différences de taille de domaines révélés par la cristallographie et l'imagerie standard. Le second objectif est d'appliquer cette méthodologie à l'analyse de facies de rupture d'éprouvettes présentant un comportement singulier (en traction ou en fatigue) pour caractériser les configurations microstructurales à l'origine de l'amorçage de fissures. Cette analyse a principalement été réalisée par polissage manuel du faciès couplé à des acquisitions EBSD mais également en exploitant le potentiel de l'imagerie 3D par MEB-FIB (Focus Ion Beam) et la technique TKD (Transmission Kikuchi Diffraction) sur lame mince prélevée au niveau d'un site d'amorçage par FIB. Enfin, cette étude expérimentale a été complétée par une première approche en simulation micromécanique sur une microstructure modèle 100% β. L'objectif était d'évaluer l'influence de l’anisotropie élastique de la phase β sur la genèse de contraintes d'incompatibilités dans les régimes élastique et élasto-plastique. L'ensemble des résultats contribue à une meilleure compréhension des variations de propriétés mécaniques en lien avec la microstructure localeThe β-metastable titanium alloys such as Ti-10V-2Fe-3Al are gradually replacing α/β alloys in aeronautical applications thanks to their improved specific strength. However, their microstructures are complex and multi-scale, consisting of a β matrix (of millimetric grains) partially transformed into primary αp nodules (micrometric) and secondary αs lamellae (sub-micrometric). The final mechanical properties are very sensitive to local variations of the microstructure, which are not always fully controlled during forging of massive parts. Moreover, the β matrix, which represent 40% of the volume and whose elastic and plastic behavior is strongly anisotropic (like the α phase) complicates the understanding of the mechanisms of deformation. The first objective of this thesis was to efficiently characterize the microstructure/texture of the different constituents (β/αp/αs) and their heterogeneities within half-finished products and forged parts by using techniques of multi-scale characterization (neutron diffraction, electronic imaging coupled with image analysis and EBSD, reconstruction of high temperature microtextures β/αp). As a result the fragmentation of the β grains into subgrains, the αp macrozones, the destruction of the orientation relation between β/αp and the organization of the αs lamellae in colonies or basket weave was quantified and the differences in size of domains revealed by crystallography and by standard imaging were pointed out. The second objective is to apply this methodology to the analysis of fracture surfaces of samples exhibiting singular behavior (in tension or in fatigue) in order to characterize the microstructural configurations leading to early cracking. This analysis was mainly performed by manual polishing coupled with EBSD acquisitions but also by using 3D imaging by SEM-FIB (Focus Ion Beam) and TKD (Transmission Kikuchi Diffraction) technique on a thin foil FIB-extracted from the crack initiation site. Finally, this experimental study was completed by a micromechanical simulation on a 100% β model microstructure. The objective was to evaluate the influence of the elastic anisotropy of the β phase on the genesis of incompatibility stresses in the elastic and elasto-plastic regimes. The overall results contribute to a better understanding of the variations of mechanical properties related to the local microstructure
Book chapters on the topic "Β-Metastable":
1
Appolaire, Benoît, Elisabeth Aeby-Gautier, Moukrane Dehmas, Amico Settefrati, Maeva Cottura, Alphonse Finel, and Yann Le Bouar. "Modeling of Phase Transformations in β-Metastable Ti Alloys." In Proceedings of the 13th World Conference on Titanium, 461–70. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119296126.ch72.
2
Zheng, Yufeng, John M. Sosa, Robert E. A. Williams, Yunzhi Wang, Rajarshi Banerjee, and Hamish L. Fraser. "Development of Ultrafine α Microstructures in a Metastable β Titanium Alloy." In Proceedings of the 13th World Conference on Titanium, 521–27. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119296126.ch83.
3
Lenain, Astrid, Nicolas Clément, Muriel Véron, and Pascal J. Jacques. "Characterisation of the Phase Transformations in a Metastable β Titanium Alloy." In THERMEC 2006, 3712–17. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-428-6.3712.
4
Salib, Matthieu, Mien Teixeira, Lionel Germain, Benoit Denand, Nathalie Gey, and Elisabeth Aeby-Gaurier. "Influence of α Precipitation at β/β Grain Boundaries on a Microtexture in A β- Metastable Titanium Alloy with and without Previous Deformation." In Proceedings of the 13th World Conference on Titanium, 405–14. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119296126.ch63.
5
Iijima, Mayumi, and Kazuo Onuma. "Octacalcium Phosphate Overgrowth on β-Tricalcium Phosphate Substrate in Metastable Calcium Phosphate Solution." In Biomineralization, 267–72. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-1002-7_28.
6
Emura, Satoshi, Baozhen Jiang, Koichi Tsuchiya, and Donald S. Shih. "Influence of Cold Caliber Rolling on α Phase Formation in Metastable β Ti Alloys." In Proceedings of the 13th World Conference on Titanium, 779–82. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119296126.ch131.
7
Helstroffer, Aurélien, Patrick Villechaise, Pascal Gadaud, and Sandra Andrieu. "Effect of Crystallographic Texture on Elastic Properties of Ti-5553 β-Metastable Titanium Alloy." In Proceedings of the 13th World Conference on Titanium, 877–84. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119296126.ch150.
8
Ma, Xinkai, Fuguo Li, Zhankun Sun, Junhua Hou, Xiaotian Fang, Yuntian Zhu, and Carl C. Koch. "Achieving Gradient Martensite Structure and Enhanced Mechanical Properties in a Metastable β Titanium Alloy." In Heterostructured Materials, 559–82. New York: Jenny Stanford Publishing, 2021. http://dx.doi.org/10.1201/9781003153078-34.
9
van Bohemen, S. M. C., Jilt Sietsma, and Sybrand van der Zwaag. "On the Nature of the Growth of Bainitic α plates in Metastable β Ti Alloys." In THERMEC 2006, 3684–89. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-428-6.3684.
10
Kim, Won Yong, and Han Sol Kim. "Effect of Oxygen on Elastic Modulus and Mechanical Property of Metastable β TiNbO Based Alloys." In Advanced Biomaterials VII, 549–52. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-436-7.549.
Conference papers on the topic "Β-Metastable":
1
Illarionov, A. G., S. I. Stepanov, and S. L. Demakov. "Fracture surface analysis of a quenched (α+β)-metastable titanium alloy." In MECHANICS, RESOURCE AND DIAGNOSTICS OF MATERIALS AND STRUCTURES (MRDMS-2017): Proceedings of the 11th International Conference on Mechanics, Resource and Diagnostics of Materials and Structures. Author(s), 2017. http://dx.doi.org/10.1063/1.5017369.
2
Ivasishin, Orest, Pavlo Markovsky, Marta Pozuelo, and Sergey V. Prikhodko. "Effect of Severe Hot Forging and Rolling on Microstructure, Texture and Tensile Properties of Titanium Metastable Beta-Alloys." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-63767.
Abstract:
The influence of specific method of severe hot deformation, forging plus rolling, that ensures true deformation |ε| = 1.39 in single pass was studied on two metastable β-class titanium alloys VT22 (Ti-5.0Al-4.79Mo-4.70V-0.97Fe-0.71Cr) and TIMETAL-LCB (Ti-1.50Al-6.82Mo-4.47Fe), wt%. The results on microstructure, crystallographic texture and tensile properties are presented. It was found that this type of severe deformation forms elongated not-recrystallized β-microstructure with sharp axial (110)β texture, and fine α-precipitates inside the β-grains. In as-deformed condition both alloys are characterized by high tensile strength (above 1500 MPa) and very low ductility. Additional annealing at α + β temperatures does not change β-grain microstructure and crystallographic texture, but gives the structure a balance of strength and ductility. It looks very attractive for practical application of the alloys. Results are discussed in terms of specific mechanism of deformation accommodation.
3
Li, Zhuoqun, and Xin Wu. "Inner Surface Cracking of an Aluminum Alloy in Small-Radius Bending." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-42976.
Abstract:
Aluminum alloys, due to their low density, high strength to weight ratio and formability, are widely used in automotive components. At present, most of the sheet alloy being used is AA6111; an Al-Mg-Si alloy with addition of Cu. AA6111. These alloys contain micrometer sized inclusions and second phase particles, with good combination of strength and formability [1]. However, at the same time, the formability of AA6111 is also limited because of these micro-sized inclusions and second phase particles [2]. To improve the formability of sheet metal used as automotive body such as panels, a newer alloy AA6022 containing nano-sized strengthening precipitates and enhanced formability has been developed. A number of research works have been done on the precipitation sequences and phase development during aging of these alloys. Recently Miao and Laughlin have reported that the precipitation sequence in the AA6022 is in the following reaction: solid solution α → GP zones → β″ → β′ + lath-like precipitate ← β + Si [3, 4]. As to AA6111, the sequence of precipitation is believed to initiate with the metastable phases, β″ and β′ leading to the equilibrium β phase. The structure and composition of the β phase have been well established to be of the fluorite structure with a composition Mg2Si [5–7]. Recent works also report the presence of a quaternary phase, Q and its metastable precursor, Q′ in the precipitation sequence [8]. The aim of this report is to find the relationship between the microstructure and the failure of the hole expanded and small angle bended samples. We will report a finding of inner surface fracture during small-radius bending due to the tensile residual stress development in the inner surface.
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Babanli, Mustafa, Sayami Huseynov, Lesya Demchenko, Vusal Huseynov, and Anatoliy Titenko. "Effect of Low-Temperature Aging on Mechanical Behavior of Metastable β-Type Ti-Mo-Sn Alloys." In 2022 IEEE 12th International Conference Nanomaterials: Applications & Properties (NAP). IEEE, 2022. http://dx.doi.org/10.1109/nap55339.2022.9934634.
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Gutierrez, S., and F. Gitzhofer. "Induction Plasma Synthesis of MoSi2 Ultrafine Powders." In ITSC2001, edited by Christopher C. Berndt, Khiam A. Khor, and Erich F. Lugscheider. ASM International, 2001. http://dx.doi.org/10.31399/asm.cp.itsc2001p0211.
Abstract:
Abstract Ultrafine MoSi2 powders have been synthesized from commercial MoSi2 powders by using an Ar-H2 induction plasma. Reactor pressure and plate power were taken as the experimental parameters to optimize the phase as well as the size distribution of ultrafine MoSi2 powders. The powders were collected from porous metal fibers. They were composed of both metastable hexagonal structure (β-MoSi2) and stable tetragonal structure (α-MoSi2) with small levels of Mo5Si3 and free silicon.
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Hagen, Alexander R., Thomas F. Grimes, Brian C. Archambault, Trevor N. Harris, and Rusi P. Taleyarkhan. "Characterization and Optimization of a Tensioned Metastable Fluid Nuclear Particle Sensor Using Laser Based Profilimetry." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-30325.
Abstract:
State of the art neutron detectors lack capabilities required by the fields of homeland security, health physics, and even for direct in-core nuclear power monitoring. A new system being developed at Purdue’s Metastable Fluid and Advanced Research Laboratory in conjunction with S/A Labs, LLC provides capabilities the state of the art lacks, and simultaneously with beta (β) and gamma (γ) blindness, high (> 90% intrinsic) efficiency for neutron/alpha spectroscopy and directionality, simple detection mechanism, and lowered electronic component dependence. This system, the Tensioned Metastable Fluid Detector (TMFD) [3], provides these capabilities despite its vastly reduced cost and complexity compared with equivalent present day systems. Fluids may be placed at pressures lower than perfect vacuum (i.e. negative) [4, 5], resulting in tensioned metastable states. These states may be induced by tensioning fluids just as one would tension solids. The TMFD works by cavitation nucleation of bubbles resulting from energy deposited by charged ions or laser photon pileup heating of fluid molecules which are placed under sufficiently tensioned (negative) pressure states of metastability. The charged ions may be created from neutron scattering, or from energetic charged particles such as alphas, alpha recoils, fission fragments, etc. A methodology has been created to profile the pressures in these chambers by lasing, called Laser Induced Cavitation (LIC), for verification of a multiphysics simulation of the chambers. The methodology and simulation together have lead to large efficiency gains in the current Acoustically Tensioned Metastable Fluid Detector (ATMFD) system. This paper describes in detail the LIC methodology and provides background on the simulation it validates.
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Chakravarty, H., J. Ballor, and C. J. Boehlert. "Effect of Alloying Additions of Aluminium and Iron on the Creep Resistance of Ti-12Cr (wt.%)." In HT2019. ASM International, 2019. http://dx.doi.org/10.31399/asm.cp.ht2019p0355.
Abstract:
Abstract Titanium (Ti) and its alloys are among the desired materials for biomaterial, marine, and aerospace applications due to their excellent properties. Metastable beta titanium (β-Ti) alloys exhibit enhanced strengths and hardness values after thermomechanical processing (TMP) due to the presence of omega (ω) and alpha (α) phase precipitates in the beta (β) matrix. In this study, the creep properties of three different β-Ti alloys, Ti-12Cr-1Fe-3Al (wt. %), Ti-12Cr-3Al (wt. %), and T- 12Cr (wt. %), were experimentally obtained at different applied stresses and at 683 K. The relationship between microstructure and creep properties was investigated. X-ray diffractometer (XRD), optical microscope (OM), and scanning electron microscope (SEM) were used to help characterize the microstructure before and after creep deformation. The hardness of alloys increased after heat treatment for 48 hrs at 410 ºC due to the precipitation of the α and ω phases. The creep tests showed that Ti-12Cr-1Fe-3Al (wt. %) was the most creep resistant and Ti-12Cr (wt. %) was the least creep resistant.
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Westphal, Moritz, Ralf Engels, Nicolas Faatz, Chrysovalantis Kannis, Berthold Klimczok, Aditya Mandiwal, Maike Maubach, and Helmut Soltner. "Measurement of the occupation number of metastable atoms in the hyperfine-substate β$_3$ in an atomic hydrogen beam." In 19th Workshop on Polarized Sources, Targets and Polarimetry. Trieste, Italy: Sissa Medialab, 2023. http://dx.doi.org/10.22323/1.433.0007.
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Yumak, Nihal, Kubilay Aslantas, and Waleed Ahmed. "Effect of Aging Treatment on the Initiation and Propagation of Fatigue Cracks in the Ti-15V-3Al-3Sn-3Cr Metastable β Titanium Alloy." In 2020 Advances in Science and Engineering Technology International Conferences (ASET). IEEE, 2020. http://dx.doi.org/10.1109/aset48392.2020.9118214.
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"Production of thermally stable alloyed carbon composite materials containing g-C3N4, β-Si3N4 and Si2N2O phases." In II All-Russian Scientific Conference "Science, Technology, Society". Krasnoyarsk Science and Technology City Hall, 2022. http://dx.doi.org/10.47813/nto.2.2022.5.14-25.
Abstract:
The article proposes a technology for alloying nanostructured carbon material with Taunite nitrogen and silicon, combining mechanochemical synthesis in a spherical planetary mill and multistage heat treatment up to 1100°C. Mechanochemical methods of processing carbon material make it possible to obtain structural-phase states in it containing metastable phases and amorphous (non-crystalline) structures that cannot be realized by other methods. The selected processing parameters contribute to achieving a uniform phase distribution in the synthesized carbon composite material. The combination of mechanochemical methods and subsequent annealing becomes an alternative basis for the technology of obtaining alloyed carbon composite materials containing phases of silicon nitride and oxynitride. The main technological task in creating such a material is to achieve the necessary balance to maintain a certain balance between the phases: carbon - silicon nitride - silicon oxynitride - phases of alloying elements. The phase composition of the obtained samples was investigated by X-ray diffractometry, the porosity and distribution of chemical elements in the samples of the obtained material was estimated using X-ray tomography and scanning electron microscopy. Based on the results obtained, conclusions are formulated about the formation of phases of graphite-like carbonitride, nitride and oxynitride of silicon in a thermally stable nanocarbon material.