High-temperature titanium alloys are approaching intrinsic performance limits, while discontinuous TiB whisker-reinforced composites provide a possible route to higher service temperatures. The central challenge is to improve strength without sacrificing ductility, especially because deformation and fracture are strongly governed by reinforcement interfaces. Here, a hot-extruded TiB/Ti65 composite is developed with ultimate tensile strengths of 1342 MPa at room temperature and 570 MPa at 800 °C. The composite also retains 21.5% ductility at 800 °C, showing a superior strength and ductility combination compared with most reported high-temperature titanium materials. By combining three-dimensional tomography, atomic-resolution microscope, in-situ micromechanical testing, and first-principles calculations, we reveal a Si-segregated TiB/α-Ti interface with enhanced adhesion work. This interface strengthens load transfer to aligned TiB whiskers and promotes pyramidal 〈c+a〉 slip in adjacent α-Ti, thereby improving local deformation compatibility. As a result, interfacial decohesion is suppressed, and ductile fracture is maintained at elevated temperature. These results demonstrate that atomic-scale chemical tailoring of reinforcement interfaces is an effective strategy for overcoming the strength and ductility trade-off in titanium matrix composites designed for extreme environments.

Although thermal exposure is a commonly used engineering process to enhance the properties of titanium alloys by diffusing oxygen onto the surface, the mechanism by which it affects fatigue performance is not fully understood. This work systematically investigates the effect of thermal exposure on the fatigue properties of a near-α titanium alloy through a combination of fatigue testing, in-situ nanoindentation, micropillar compression experiments, and an integrated differential phase contrast (iDPC)-scanning transmission electron microscope (STEM), particularly emphasizing the inhibitory role of surface oxygen-enriched layer on fatigue crack propagation. Results show that after thermal exposure, the oxygen-enriched layer formed on the alloy’s surface relieves surface stress concentration, thus enabling the alloy to maintain high fatigue strength even after up to 107 fatigue cycles at 650 MPa. Interstitial oxygen atoms within the oxygen-enriched layer induce lattice distortion and promote the formation of oxygen-enriched stacking faults at fatigue crack tips. These oxygen-enriched stacking faults efficiently absorb energy required for crack propagation, deflect the crack propagation path, extend the propagation period, and alleviate stress concentration; these effects collectively enhance the fatigue resistance of the alloy. This work systematically elucidates the mechanism by which the oxygen-rich layer delays crack propagation through microstructural regulation, providing a theoretical basis for designing high-performance titanium alloys.

The optimized accelerated multi-phase field model was used to investigate the influence of magnitude and distribution of stored energy on the grain growth of alloy microstructures. The results show that the model successfully simulates and accelerates the microstructure evolution of a system with multiple order parameters. An increase in stored energy of alloy accelerates grain growth, leading to an increase in average grain size. During the early-to-mid stages of microstructure evolution, grains with high stored energy reduce the uniformity of local grain sizes. An increase in the non-uniformity of stored energy distribution can expedite the release process of stored energy in the early-to-mid stages of microstructure evolution, leading to a larger grain size. In the later stage, smaller and more uniform grain size is obtained. This research develops a polycrystalline geometric model for integrated microscale simulation of alloys, providing a theoretical basis for analyzing fine-scale parameter changes in grain size after high-temperature deformation.

In this study, hot-compression tests of Ti6246 alloy were performed in the beta single-phase region under various temperatures, strain rates, and deformation levels, followed by isothermal heat treatments with various durations. The resulting microstructures were characterized using OM, SEM, and EBSD, enabling a systematic investigation of microstructural and crystallographic texture evolution, as well as the variant-selection behavior associated with alpha-phase colony precipitation. The results reveal that deformation promotes the development of a pronounced <100> beta-fiber texture, and the relative intensity of this component increases with strain. At higher strain rates, however, the texture transitions into a hybrid state comprising a dominant <100> component and a weaker <111> component. Furthermore, coarse alpha clusters preferentially form at grain boundaries between {100}-oriented and {111}-oriented beta grains, whereas their formation is markedly suppressed at boundaries between beta grains sharing the same {100} orientation.

Basal fracture due to dwell fatigue (DF) is primary cause of core material failure during aero-engine service, which highlights the importance of understanding the crack initiation mechanism. In this study, the relationship between activation of plastic slip within the [0 0 01] basal plane orientation, local strain and crack initiation in near-alpha Ti60 alloys was investigated using coupled in situ and high-resolution digital image correlation (HR-DIC) methods. The results show that basal slip is preferentially activated resulting into a higher shear strain in DF compared to [101 0] prismatic orientation grains. Two types of cracking induced by strong basal slip were identified in grains with medium to high basal Schmidt factor (SF): slip transgranular cracking and basal twist grain boundary (BTGB) cracking. The slip deformation and strain evolution of the two types of cracks before and after their initiation were observed for the first time on the sample surface by in-situ dwell, which provides experimental and theoretical support for their formation mechanism. In order to constitute potential locations for crack nucleation, these regions have high local and shear strains during the basal slip stage prior to crack initiation. The higher local strain in the former is attributed to the intrusion and extrusion mechanism of the slip bands, while the latter is attributed to the inconsistency of the slip deformation of the microscopic dislocations on both sides of the BTGB making the GB slip-shear. Additionally, the incoordination on both sides of the GB, coupled with the inherently low cleavage energy, makes the BTGB more susceptible to cracking compared to slip transgranular cracking. No elemental segregation or beta-phase influence was observed at the grain boundary interface. This study provides new insights into the mechanisms involved basal slip-induced cracking in Ti alloys subjected to dwell loadings. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

As a common microstructural feature in titanium alloys, microtexture significantly influences alloy mechanical properties. It is crucial to deeply analyze its impact and underlying mechanisms on the microstructure and texture evolution during hot processing. This work investigated crystal orientation evolution of Ti60 alloy with different-strength microtextures during α+β deformation, and analyzed the influence mechanisms of the microtexture on the texture evolution and variant selection. The results show that significantly different orientation evolutions exhibited between strong and weak microtexture alloys during deformation, leading to distinct deformation textures. For instance, the texture in the weak microtexture alloy was predominantly characterized by the <11-20>//CD component, whereas that in the strong one was dominated by the component distributed along RDs in {0001} pole figure. The difference in texture evolution is primarily attributed to the influence of the Burgers orientation relationship between the primary α and prior β phases. In the strong microtexture alloy, the activation of extensive prismatic slip in primary α grains resulted in a dominant texture component that maintains a high degree of Burgers orientation relationship with the prior β phase. Thus, the strong microtexture alloy obtained more low-angle αp/β boundaries compared with the weak one. These low-angle boundaries could induce the variant selection during β→α phase transformation by coordinating the slip transfer in the primary α and the neighbouring β phases. Consequently, this led to a secondary α texture that resembles the primary α phase, further exacerbating the disparity in deformation texture compared to the weak microtexture alloy.

Understanding the microstructural evolution and phase interactions during thermal deformation of the Ti2AlNb alloy below the B2 transformation point is crucial for optimizing its thermal processing. This study systematically investigates the dynamic spheroidization of layered O-phase and the dynamic recrystallization behavior of the B2 matrix during compression below the B2 transformation point. Results indicate that the initial thickness of Ophase lamellae significantly influences their dynamic spheroidization process, with thicker lamellae requiring greater height reduction to achieve complete spheroidization. O-phase spheroidization primarily occurs via an interfacial separation mechanism: O/O interfaces first form within the O-phase through dislocation evolution and subgrain boundary formation. Subsequently, the B2 phase wedges along these interfaces, creating interfacial grooves. Driven by interfacial energy, migration and diffusion occur, ultimately leading to lamella separation and spheroidization. The study also reveals synergistic evolution between the O phase and B2 phase during deformation: continuous dynamic recrystallization, preferentially activated in the B2 phase, induces stress concentration at interfaces, thereby initiating slip systems in the O phase and promoting O-phase recrystallizationrelated evolution. Concurrently, already spheroidized O phase particles act as nucleation sites, facilitating dynamic recrystallization nucleation of the B2 phase at O/B2 interfaces. This study elucidates the interactive mechanism between lamellar O-phase spheroidization and B2-phase recrystallization in Ti2AlNb alloys, providing theoretical guidance for regulating microstructure and enhancing alloy performance through thermal deformation processes.

Micro-texture regions (MTRs), arising from the combined influences of prior beta orientations and secondary-alpha (alpha s) variant selection, are pervasive in forged titanium alloy disks and critically degrade deformation uniformity and mechanical reliability. Their resistance to orientation homogenization renders MTR weakening a key challenge for fabricating high-performance titanium alloys. In this study, Ti60 alloy with pronounced MTRs was processed through various sub-transus thermomechanical processing routes to clarify the underlying mechanisms and identify effective weakening strategies. Multiscale characterization and improved quantitative evaluations of MTR intensity and Burgers orientation relationship (BOR) deviation were employed to correlate microstructure evolution with crystallographic orientation regulation. Results demonstrate that coordinated regulation of primary-alpha (alpha p) recrystallization, beta-grain growth, and alpha s precipitation governs MTR weakening. Direct heat treatment preserved concentrated alpha p orientations and BOR, sustaining stable MTRs. Compression near the sub-transus temperature significantly increased BOR deviation and mitigated variant selection but generated deformation texture due to orientation inheritance. In contrast, low-temperature dual-phase compression followed by hightemperature heat treatment achieved the most effective MTR weakening (0.732 -> 0.141) while avoiding deformation texture formation. Low-temperature compression facilitates alpha p orientation dispersion and supplies the driving force for static recrystallization and phase transformation, enabling the formation of beta grains and alpha s precipitates with more uniform orientations. MTRs with c-axes perpendicular to the compression direction exhibit exceptional stability in thermomechanical processing due to preferential prismatic slip. These findings establish a comprehensive mechanistic framework for MTR weakening and provide processing guidance for orientation homogenization in advanced disk-grade titanium alloys.

Plastic deformation is affected by intrinsic slip anisotropy in the α2 phase and slip-transfer capability across α2/β interfaces in Ti2AlNb alloys. Orientation-controlled micropillar compression is used to decouple these contributions, and slip misorientation serves as a quantitative measure of interface compatibility. In intragranular α2 pillars with small slip misorientation, pronounced orientation dependence is observed. The 〈101¯0〉 orientation promotes early multi-slip and strong hardening, 〈0001〉 shows weak hardening due to limited dislocation storage and surface escape, whereas 〈112¯0〉 yields at low stress with marked stress drops indicative of avalanche-like plasticity. When slip misorientation is large, interfacial slip transfer is suppressed, leading to slip termination and delayed α2 activation. These results show that intrinsic α2 orientation, together with slip misorientation, affects plastic deformation in Ti2AlNb.

Hot spinning is a near-net-shape technique for manufacturing complex profiled rings from high-temperature titanium alloys. However, the inherent localized deformation introduces through-thickness gradients in stored energy, causing heterogeneous microstructural evolution that conventional single-step annealing cannot resolve. For a hot-spun Ti65 ring with a high-energy outer surface and a low-energy inner surface, a two-stage heat treatment is proposed: a 650 °C pre-treatment followed by 990 °C annealing in the α + β phase field. Electron backscatter diffraction and transmission electron microscopy show that the 650 °C pre-treatment serves a dual role. In high-energy regions, it initiates partial recrystallization and equiaxed grain formation, consuming part of the stored energy and suppressing abnormal coarsening. In low-energy regions, it introduces dislocation cells and silicide precipitates, redistributing stored energy and providing abundant nucleation sites. TEM analysis of a short-time 990 °C annealed sample reveals small recrystallized α grains closely associated with pre-existing silicides, indicating that the precipitates act as heterogeneous nucleation cores. This preconditioning synchronizes static recrystallization and phase transformation across the entire cross-section during the subsequent anneal, eliminating the initial gradient and producing a uniform microstructure with consistent αp content and restored crystallographic relationships. Microhardness measurements further confirm that the through-thickness hardness gradient observed after conventional annealing is virtually eliminated by the two-stage treatment. These findings suggest that stored energy redistribution via an intermediate-temperature pre-treatment offers an effective strategy for overcoming the limitations of conventional heat treatment, and the approach could be extended to mitigate deformation-induced microstructural gradients in other hot-working processes.

This study examines the failure of TA11, TC4, and Ti60 titanium alloys under mechanical loading in a moist environment rich in NaCl at 600 degrees C. It focuses on how creep deformation interacts with hot salt stress corrosion cracking (HSSCC). In alloys with poor creep resistance, creep deformation reduces the stress concentration at the tips of corrosion-induced cracks. On the other hand, rapid corrosion accelerates the process of HSSCC. Crosssection morphology was statistically analyzed to explore the relationships among crack initiation, crack propagation, and corrosion behavior in a NaCl-deposited environment. The factors influencing corrosion were investigated by comparing microstructural features and alloying chemistry among the three alloys.

In this study, Ti60 high-temperature titanium alloy was selected as the research material to systematically investigate the effects of different post-bond heat treatment temperatures on the interfacial microstructure and mechanical properties of diffusion-bonded joints. The results indicate that heat treatment can effectively induce interfacial microstructure reconstruction through recovery and recrystallization within the diffusion bonding zone, thereby reducing the adverse effects of crystallographic mismatch and significantly enhancing the mechanical performance of the alloy. After heat treatment at 1015 °C for 2 h, the diffusion-bonded Ti60 alloy exhibited an ultimate tensile strength of 1081.5 MPa and an elongation of 14.25%, demonstrating an excellent balance between strength and ductility.

The fundamental understanding of how TiB particles regulate the alpha-phase heterogeneous nucleation mechanism and texture evolution in TiB reinforced alpha+beta titanium alloys during thermo-mechanical processing remains incomplete, which limits the precise optimization of their microstructure and service performance. To address this issue, TiB reinforced alpha+beta titanium alloys were fabricated via in-situ reaction hot pressing, and hot compression tests were combined with advanced characterization techniques (SEM, EBSD, HRTEM) and molecular dynamics (MD) simulations for systematic investigation. Results demonstrate that TiB particles disperse uniformly in the matrix and act as effective heterogeneous nucleation sites for alpha grains, which follow a specific crystallographic orientation relationship of {0001}(alpha)//{001}(TiB) and <11-20>(alpha)//<010>(TiB), forming low-energy semi-coherent interfaces (minimum 0.89 J/m(2) for the {0001}(alpha)//{001}(TiB) configuration); with increasing compression strain, the alpha texture gradually weakens and becomes randomized (in contrast to the BOR dominated strong texture in traditional alpha+beta titanium alloys), accompanied by grain refinement and reduced material anisotropy. The underlying mechanism lies in TiB-induced heterogeneous nucleation that disrupts the conventional BOR-governed alpha texture evolution, driven by the thermodynamically favorable formation of low-energy semi-coherent alpha-Ti/TiB interfaces. This work provides a comprehensive theoretical basis for optimizing the thermo-mechanical processing parameters of TiB reinforced alpha+beta titanium alloys, facilitating the tailored design of their microstructure and the enhancement of mechanical properties for advanced engineering applications.

This work links beta texture, phase transformation misorientation-governed variant selection and mechanical anisotropy, providing guidance for optimizing thermomechanical processing to tailor microstructure and properties. The role of deformation-induced beta texture in variant selection during beta ->alpha phase transformation in titanium alloys remains poorly quantified, and existing empirical criteria such as the common {110} pole show limitations. In this work, a high-temperature titanium alloy was subjected to uniaxial compression in the beta phase region at different reductions, followed by electron backscatter diffraction characterization, phase transformation misorientation calculation, statistical simulation, in-situ tensile and micropillar compression tests. Increasing deformation strengthens <100>//CD and <111>//CD beta fibers, promoting preferential alpha variants with <11-20>//CD and <10-11>//CD textures. The phase transformation misorientation analysis reveals that <100>/<111> beta grain pairs exhibit a 95.4% cumulative frequency of phase transformation misorientation within 15 degrees, explaining the strong variant selection tendency. Micromechanical testing demonstrates that <1011>-oriented alpha variants possess significantly higher deformation resistance than <11-20>-oriented ones due to lower Schmid factors for basal and prismatic slip. This work establishes a quantitative link among beta texture, phase transformation misorientation controlled variant selection, and alpha phase mechanical anisotropy, providing a basis for tailoring thermomechanical processing to achieve desired alpha textures and improved properties in titanium alloys.

Dual-phase titanium alloys rely heavily on α phase microstructure and morphology for property optimization, making it crucial to elucidate the formation mechanism of α colony. This work systematically investigates the variant selection, nucleation and growth of α colonies in a Ti60 titanium alloy during β hot deformation, further elucidating the influence of β grain boundary characteristics on their formation. The results indicate that the formation of α colony is synergistically influenced by the grain boundary misorientation and plane inclination. For neighbouring β grains satisfying the common <110> condition, only when the α/β habit planes {10-10}α//{1-12}β or {0001}α//{110}β are nearly parallel to the grain boundary plane inclination can the preferred α variant formed by misorientation-dominated variant selection form colony morphology. Meanwhile, α colony undergoes slight internal crystallographic rotations, enabling them to grow along another set of habit plane within the β grain; the inclination angle between this habit plane and the β grain boundary plane dictates the spatial orientation and trace direction of the α colony. These findings provide a refined theoretical framework for the precise regulation of α lamellae/colonies in titanium alloy hot working processes.

In ordered intermetallics, defects can degrade long-range order, yet atomic-scale evidence and mechanistic understanding of this process remain limited, especially in the alpha 2 phase of Ti2AlNb alloys. We probe order degradation in the alpha 2 phase of a Ti2AlNb alloy by in situ micropillar compression. Among the planar defects associated with order degradation, we reveal two representative types. One is a slip-induced antiphase domain boundary, which forms after the glide of a Shockley partial dislocation and is removed when a second partial dislocation glides on the same plane, providing direct atomic-resolution evidence for a formation-removal pathway in alpha 2. The other is a chemistry-associated order-disorder interface, where the locally disordered regions retain the hexagonal lattice framework but show weakened or absent superlattice reflections together with locally reduced Al content. These findings highlight local ordering stability as an important structural factor for understanding deformation in Ti2AlNb and related ordered intermetallics.

A microstructure-dependent deformation framework was established for a Ti-22Al-24Nb-0.5Mo alloy by systematically decoupling the roles of the α2 phase, primary O (Opri) phase, and secondary O (Osec) precipitates through a stepwise heat-treatment strategy. This phase-by-phase microstructural design enables a direct elucidation of their individual and synergistic contributions to tensile deformation. Three representative microstructures, namely B2+α2, B2+α2+Opri, and B2+α2+Opri+Osec, were constructed and investigated by room-temperature load-unload tensile testing combined with SEM, EBSD, and TEM characterizations. The results show that the slip behavior of the B2 matrix evolves from single slip to duplex slip and finally to cross-slip with increasing strain. In the B2+α2 microstructure, intragranular α2 shows a limited blocking effect on slip-trace continuity, whereas grain-boundary α2 acts as the dominant obstacle to long-range slip propagation. In the B2+α2+Opri microstructure, the Opri phase promotes orientation-dependent slip transfer and slip deflection, thereby enhancing deformation compatibility and strain-hardening. Further introduction of fine acicular Osec precipitates effectively suppresses continuous slip propagation, leading to a marked increase in tensile strength and work-hardening capacity. These findings clarify the distinct deformation roles of the constituent phases over different strain regimes and provide mechanistic guidance for phase engineering and microstructural design of Ti2AlNb-based alloys.

Nitride coatings can improve the resistance of structural materials to tritium permeation in fusion reactors; however, research on the adhesion between the coating and substrate remains limited. In this work, three nitride coatings: TiN, AlTiN, and AlCrN were deposited on reduced-activation ferritic/martensitic (RAFM) steel using physical vapor deposition (PVD), and their bonding performance was systematically evaluated using Rockwell indentation, scratch testing, and microstructural analysis. All three coatings achieved a Rockwell indentation adhesion rating of Class 1. The TiN coating exhibited the highest critical load (Lc2 ' = 15.8 N) and the best crack resistance, attributed to its high crystallinity, dense microstructure, and maximum thickness. The AlCrN coating showed moderate bonding performance (Lc2 = 13.0 N), while maintaining good edge integrity due to the presence of a stable face-centered cubic-CrN phase and surface droplets. The AlTiN coating displayed the lowest critical load (Lc2 = 12.4 N) and the poorest crack resistance, associated with its relatively low crystallinity and surface pit defects. These results indicate that the bonding performance and failure behavior of PVD nitride coatings on RAFM steel are primarily governed by crystallinity, microstructure, and the type of surface defects.

Due to their excellent performance, near alpha and alpha +beta dual-phase titanium alloys are critical materials in aerospace engineering. Enhancing the performance stability of titanium alloy forgings has become a focal point of research in engineering applications. However, the microtextures within these forg ings significantly affect key properties such as fatigue resistance, which limits the overall performance of titanium alloy forgings. Recent studies indicate that optimizing the hot working process to improve the crystallographic orientation and microstructure uniformity is an effective means of enhancing alloy performance. This study reviews the origins of microtextures in titanium alloy forgings, their potential negative effects, and the optimization processes involved. Finally, the study presents several research guidelines aimed at improving the microstructural uniformity of titanium alloy forgings.