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Intermetallic titanium aluminides, leveraging the ordered γ-TiAl phase, attract increasing attention in aerospace and automotive engineering due to their favorable mechanical properties at high temperatures. Of particular interest are γ-TiAl-based alloys with a Niobium (Nb) concentration of 5–10 at.%. It is a key question how to model such ternary alloys at the atomic scale with molecular dynamics (MD) simulations to better understand (and subsequently optimize) the alloys. Here, we present a comparative analysis of ternary TiAlNb interatomic potentials developed by the moment tensor potential (MTP) and deep potential molecular dynamics (DeePMD) methods specifically for the above mentioned critical Nb concentration range. We introduce a novel dataset (TiAlNb dataset) for potential training that establishes a benchmark for the assessment of TiAlNb potentials. The potentials were evaluated through rigorous error analysis and performance metrics, alongside calculations of material properties such as elastic constants, equilibrium volume, and lattice constant. Additionally, we explore finite temperature properties including specific heat and thermal expansion with both potentials. Mechanical behaviors, such as uniaxial tension and the calculation of generalized stacking fault energy, are analyzed to determine the impact of Nb alloying in TiAl-based alloys. Our results indicate that Nb alloying generally enhances the ductility of TiAl-based alloys at the expense of reduced strength, with the notable exception of simulations using DeePMD for the γ-TiAl phase, where this trend does not apply. [ABSTRACT FROM AUTHOR]

The structure and phase composition of powder materials of the Ti–Al–B system formed in the process of vacuum sintering and synthesis in the mode of high temperature self-propagating synthesis (SHS) are considered depending on the combination of components in the form of elementary powders (Ti, Al and B) and using the finished titanium diboride (TiB2) compound. The proportions of the components were calculated in such a way that the number of interacting elements was sufficient to form a two-phase TiAl3 + TiB2 composition. When sintering the Ti + Al + TiB2 mixture, the diboride is retained, but the presence of TiB is noted as a result of the redistribution of boron due to its migration into free titanium. It was discovered that sintering of compacts from the mixture based on elemental powders (Ti, Al and B) occurs under conditions of high exothermic effect, as a result of which the samples were destroyed. This made it possible to use this mixture under conditions of high-temperature synthesis in combustion mode. As a result of both vacuum sintering and SHS compacting, aluminide TiAl3 and titanium diboride (TiB2) are mainly formed from a mixture of elemental powders (Ti, Al and B). In this case, some transition phases can be observed. It is shown that after the synthesis of the Ti + Al + B mixture, it is possible to obtain a powder product from which compacts are well sintered while maintaining their shape with a slight shrinkage. [ABSTRACT FROM AUTHOR]

The creep properties of fully lamellar γ/α2 titanium aluminides can be significantly improved by alloying with Nb, Ta or Zr. While the influence of these alloying elements on the γ-phase has already been examined, their diffusivity and strengthening properties in the α2-phase are still lacking. In order to study the effect of Nb, Ta and Zr in α2-Ti3Al, the alloys Ti-33Al, Ti-33Al-5Nb, Ti-33Al-5Ta and Ti-33Al-5Zr were investigated using a diffusion couple approach and strain rate jump tests. The results show that Zr diffuses the fastest, followed by Nb and Ta. Furthermore, these alloying elements also increase the strength compared to a binary Ti-33Al alloy, from which Zr leads to the highest strength increase followed by Ta and Nb. The lower diffusivity of Ta becomes increasingly important at higher temperatures and lower strain rates resulting in a higher strengthening potential than Nb and Zr under such conditions. [ABSTRACT FROM AUTHOR]

The TNM alloy, a βo-phase-containing TiAl alloy, has been withdrawn from use as a last-stage turbine blade in commercial jet engines as it suffered frequent impact fractures in service, raising doubts regarding the necessity of the βo-phase in practical TiAl alloys. Here, we evaluate the practical properties required for jet engine blades for various TiAl alloys and investigate the effects of the βo-phase thereupon. First, we explore the influence of the βo-phase content on the impact resistance and machinability for forged Ti–43.5Al–xCr and cast Ti–46.0Al–xCr alloys; the properties deteriorate significantly at increasing βo-phase contents. Subsequently, two practical TiAl alloys—TNM alloy and TiAl4822—were prepared with and without the βo-phase by varying the heat treatment temperature for the former and the Cr concentration for the latter. In addition to impact resistance and machinability, the creep strength is significantly reduced by the presence of the βo-phase. Overall, these findings suggest that the βo-phase is an undesirable phase in practical TiAl alloys, especially those used for jet engine blades, because, although the disordered β-phase is soft at high temperatures, it changes to significantly more brittle and harder βo-phase after cooling. [ABSTRACT FROM AUTHOR]

Cutting force monitoring may be established as a functional control system for machining processes, helping determine the optimal time for tool change since a relationship between tool wear and milling forces exists. However, these forces result from various effect, including chip removal, friction, and vibrations. Predicting the end of functional tool life becomes challenging due to these complex interactions. In this study, it is proposed a decomposed action methodology based on force analysis using the fast Fourier transform and harmonic analysis. In pursuit of a comprehensive understanding of cutting forces during milling process, it is proposed a methodology to capture the signal given by a rotary dynamometer in selective cutting tests directed to discriminate and isolate external friction and other effects. The methodology has been tuned for slot milling of Ti48Al2Cr2Nb titanium aluminide using a single uncoated tungsten carbide insert, under different combinations of depth of cut and feed per tooth, for a fixed cutting speed value. The friction force in the tool flank zone has been demonstrated as the main action due to the small chip section removed, which leads to explain the rapid tool wear in titanium aluminides machining. Friction coefficients ranging from 0.412 to 0.579 have been found in real cutting conditions. This methodology will allow the evaluation of different tool geometries to reduce tool-workpiece friction and wear phenomena, enhancing the tool life. [ABSTRACT FROM AUTHOR]

The structure, phase composition, and basic mechanical and corrosion properties of powder aluminumbased composites obtained by the hot forging (HF) method were studied. The results of studies of the microstructure of synthesized master alloy of different compositions revealed the presence of particles of the strengthening phase of different dispersion and shapes, which are rather evenly distributed in the metal matrix. The method of X-ray phase analysis established the presence of titanium and aluminum carbide, and also a number of lines belonging to titanium aluminides Al3Ti , Al5Ti3 , Al2Ti , AlTi3 , Al5Ti2. Aluminium-based composite materials were strengthened with the Al–C–Ti master alloy of various compositions. Studies of the samples obtained after HF show that the microstructure of the composites is characterized by the presence of two phases: the base, and the aluminum matrix, in which the agglomerates of the master alloy are distributed. The composites alloyed with 15 mass% of the master alloy (20Al–64Ti–16C) in the initial charge and obtained by the method of sintering and HF have increased strength characteristics and demonstrate high strength and resistance properties in a 3.5% NaCl solution, regardless of the phase composition of the master alloy. [ABSTRACT FROM AUTHOR]

The grain size of the full lamellae TiAl-based alloy changes from ~400 μm to ~40 μm through the precipitation of metastable structures by cyclic heat treatment. Based on this, two kinds of variant selection processes—coherent metastable γ variants precipitated during the air-cooling process and αs variants precipitated during the holding at a single α phase region process—are identified to promote the formation of refined Type I and Type II coherent grain boundaries. The oxidation tests at 1000 °C for 100 h show that the formation of refined coherent grain boundaries can greatly improve oxidation resistance by inducing the continuous multi-layer protective barrier consisting of (Ti, (Nb, Ta))O2, TiN, and Al(Nb,Ta)2. This protective barrier inhibits the inward diffusion of oxygen and nitrogen. [ABSTRACT FROM AUTHOR]

Titanium aluminides are being explored as potential materials for the aeronautical sector. However, their application is limited by the high costs of processing and their difficulties in machining. This research evaluates the effectiveness of the minimum quantity lubrication technique (MQL) on the turning process of Ti48Al2Cr2Nb aluminide in terms of tool wear, tool life, cutting forces, surface integrity, and temperature. It was found that MQL conditions can improve the process efficiency, reducing the thermally induced wear mechanisms and enlarging the tool life compared to dry machining. Furthermore, it allows the cutting speed to be incremented, leading to lower processing times. However, MQL seems to not be effective in the reduction of the strain-hardening effect near the machined surface and, although the number of microcracks is reduced, defect-free surfaces cannot be obtained. Moreover, similar microstructural alterations as for dry cutting were detected. The best cutting conditions in terms of surface quality were assessed using the central composite face (CCF) design and surface response methodology. Optimization of the surface roughness under industrially viable cutting conditions was achieved with an average surface roughness value, Ra, of 0.29 µm (feed rate of 0.05 mm/rev, a cutting speed of 54.6 m/min and a depth of cut of 0.125 mm). [ABSTRACT FROM AUTHOR]

High Nb–TiAl alloys fabricated using laser powder bed fusion (LPBF) exhibit a metastable α2 phase due to the rapid cooling rate of the LPBF process. However, the understanding of the structural transformation behavior in LPBF-fabricated high Nb–TiAl alloys remains limited. In this work, a high Nb–TiAl alloy with a nominal composition of Ti–48Al–2Cr–8Nb (at. %) was additively manufactured using LPBF. The structural transformation from metastable α2 phase to γ phase was then studied by the in-situ high-temperature x-ray diffraction (XRD), in-situ heating transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). Furthermore, the phase composition and microstructure of the samples annealed at different temperatures were determined by XRD and electron backscatter diffraction (EBSD). Our findings demonstrate that the α2 phase in LPBF-fabricated high Nb–TiAl alloy remains stable up to 873 K, after which it decomposes and forms fine γ lamellar colonies along with a disordered γ′ phase as an intermediate phase. Notably, the transition from α2 to γ′ phase is reversible. In contrast, the formation of the γ phase is irreversible and persists down to room temperature. It is also found that the changes in grain size and phase composition of the LPBF-fabricated high Nb–TiAl alloy have a significant impact on its hardness. This study provides valuable insights into the structural transformation behavior of additively manufactured high Nb–TiAl alloys by LPBF, offering guidance for regulating their structure and properties.

Works have been performed on optimization of the technological scheme of producing ingots for consumable electrodes with a stable chemical composition and properties. The paper presents the results of studying an ingot of 195 mm diameter from a titanium aluminide-based alloy of Ti-28Al-7Nb-2Mo system, made by double electron beam remelting. Further ingot remelting in the arc furnace was performed, which allowed producing a homogeneous and defect-free ingot of an optimal composition of Ti-28Al-7Nb-2Mo-0.3 (Y, Re, B). The influence of modifying on the structure and properties was studied. It was determined that addition of surfactants promotes refining of the structural components and improvement of the alloy mechanical properties. [ABSTRACT FROM AUTHOR]

In this research, an in situ Al-Ti composite was fabricated by a combination of accumulative roll bonding (ARB) and friction stir processing (FSP). Following 3 cycles of ARB, FSP was performed for 5 passes with 16 mm min−1-line speed and 1600 rpm rotary speed. The structure and properties of the composite were investigated using an optical microscope (OM), scanning electron microscope (SEM), x-ray diffraction (XRD), hardness test, tensile strength, and abrasion test. It was found that with an increase in the number of ARB cycles, Ti layers were broken into smaller particles. Annealing after ARB caused the formation of initial Ti-Al intermetallic particles. Moreover, performing FSP on these samples led to the formation of a nanostructure containing Ti and Ti-Al intermetallic compounds in the Al matrix. XRD results showed that the titanium aluminides produced during FSP were TiAl3. XRD patterns also showed some unreacted primary Ti particles in the composites. The hardness of the ARB sample reduced remarkably after annealing at 600 °C for 180 min. The structure of the composite was refined, and its hardness increased after the FSP process. The maximum hardness was 81.4 BHN which was obtained after 3 passes of FSP. The tensile and yield strength of Al-Ti-AlTi3 composites increased from 89 to 140 MPa compared to annealed Al. Abrasion tests showed that the wear mechanism of ARB and FSP samples was a combination of adhesive and abrasive mechanisms. [ABSTRACT FROM AUTHOR]

The TNM alloy, a βo-phase-containing TiAl alloy, has been withdrawn from use as a last-stage turbine blade in commercial jet engines as it suffered frequent impact fractures in service, raising doubts regarding the necessity of the βo-phase in practical TiAl alloys. Here, we evaluate the practical properties required for jet engine blades for various TiAl alloys and investigate the effects of the βo-phase thereupon. First, we explore the influence of the βo-phase content on the impact resistance and machinability for forged Ti–43.5Al–xCr and cast Ti–46.0Al–xCr alloys; the properties deteriorate significantly at increasing βo-phase contents. Subsequently, two practical TiAl alloys—TNM alloy and TiAl4822—were prepared with and without the βo-phase by varying the heat treatment temperature for the former and the Cr concentration for the latter. In addition to impact resistance and machinability, the creep strength is significantly reduced by the presence of the βo-phase. Overall, these findings suggest that the βo-phase is an undesirable phase in practical TiAl alloys, especially those used for jet engine blades, because, although the disordered β-phase is soft at high temperatures, it changes to significantly more brittle and harder βo-phase after cooling.

In this work, the short-term creep behaviors of high Nb containing TiAl alloys with different microstructure characteristics at 800 °C under a wide range of stresses of 150–350 MPa were investigated in detail. In order to tailor microstructure of high Nb containing TiAl alloys, composition design strategies were applied, including the change of Al content and the introduction of non-metallic element C and rare-earth oxide Y2O3. Microstructure analysis shows that increasing Al content from 43 at.% to 46 at.% will not only change the phase constitution by changing the solidification behavior, but also affect the existence form of element C, that is, in the form of dissolved carbon atoms in low-Al alloy and Ti2AlC precipitate in high-Al alloy. Creep results confirm that both increasing Al content and introducing C and Y2O3 can effectively reduce the steady-state creep rate and enhance the creep resistance, but the latter has a more significant effect. In addition, the creep behavior of high Nb containing TiAl alloys strongly depends on the stress level, and corresponding creep deformation mechanism changes from grain boundary/lamellar interface sliding under low stress to dislocation motion under high stress. Meanwhile, the correlation between the critical stress value on creep mechanism transition and the alloy composition/microstructure was clarified.

The purpose of this study is to determine if forged TiAl alloys are worth using for small parts such as jet engine turbine blades. As part of this goal, this study investigated ways to improve the impact resistance of forged TiAl alloys and compared them to cast TiAl alloys. The effects of additive elements and microstructure on the impact resistance of forged ternary TiAl alloys of 43.5 at. % Al were evaluated using the Charpy impact test on specimens heated to 500 °C prior to testing. The impact resistance of the forged alloys improved with the addition of Cr, V, and Mn and deteriorated with the addition of Nb. The impact resistance of the microstructure containing a β-phase, a common microstructure in forged TiAl alloys, was significantly lower. The fully lamellar structure obtained at the expense of forgeability showed much higher impact resistance than this. However, even the best impact resistance of the forged alloys was significantly inferior to that of cast ternary alloys of 46.5 at. % Al prepared with the same additive content. Combined with the high cost and low high-temperature strength of the forged TiAl alloys, it is concluded that it is pointless to use forged TiAl alloys for small parts that can be made via casting. [ABSTRACT FROM AUTHOR]

Vacuum brazing of Ti-47Al-2Nb-2Cr-0.15B (at%) alloy with TiH2-Ni-TiB2 powder filler in situ assisted 20 vol% TiB whiskers is performed at 1190-1250 °C for 10 min. The microstructure evolution of the joint at various brazing temperatures and the relationship between microstructure and joint properties are systematically investigated. In the results, it is indicated that the interfacial microstructure of the γ-TiAl joint brazed at 1230 °C is γ-TiAl/Ti3Alþ Al3NiTi2 (layer I)/Al3NiTi2þ Ti3Al (layer II)/Al3NiTi2þ TiBþ Ti3Al (layer III)/Al3NiTi2þ Ti3Al (layer II)/Ti3Alþ Al3NiTi2 (layer I)/γ-TiAl. The layer II containing high-hardness Al3NiTi2 is always the weakest part in the brazed joint. The microstructure refinement and load-bearing behavior of layer III are increased with brazing temperature due to the increasing length of the TiB whisker. Variation of the content of low-hardness Ti3Al in layer II as well as its microstructure refinement and internal bonding strength, the shear strength of γ-TiAl joints is first increased and then decreased with brazing temperature, but that of Al3NiTi2 in layer II is reversed. The joint brazed at 1230 °C possesses the maximum shear strength of 332.87MPa and a quasi-cleavage fracture occurs in the layer II mainly consisted of Al3NiTi2. [ABSTRACT FROM AUTHOR]

AlTiN nitride coatings on the surfaces of metal-working tools can greatly extend their service life. The coatings are deposited from plasma flows generated by vacuum arc burning on the cathode surface. The elemental and charge composition of the plasma flows, as well as the content of metal drops, depend on the cathode's structure. In this paper, the microstructure, elemental, and phase compositions of the surface layer of Al-Ti cathodes subjected to vacuum arc heating were studied. These cathodes had similar elemental compositions (Ti + 50 at.% Al) but differed from one another in their phase composition and microstructure (grain size, porosity). The cathodes were studied by X-ray diffraction analysis, scanning electron microscopy, and electron probe analysis. It was found that during vacuum arc heating, surface fusion or thermal cracking of the cathode's surface layer occurs. The thickness, structure, and phase composition of the modified layer were controlled by the thermal conductivity of the cathode material, which, in turn, depended on the phase composition and porosity of the cathodes. The maximum thickness of the modified layer (up to 400 µm) was observed on the surface of the sintered cathode due to the lower thermal conductivity of the porous structure of the cathode. The obtained results can be used for the development of coating deposition technology based on vacuum arc sputtering of multicomponent cathodes. [ABSTRACT FROM AUTHOR]

The addition of minor fractions of grain refiners commonly improves the mechanical properties of TiAl intermetallic alloys. In this study, Ti-36 wt.% Al powders were consolidated using a field-assisted sintering technique without adding grain refiners. Various temperatures (650–1300 °C) and pressures (14–50 MPa) were used to elucidate the structure–property relationship. An intermetallic of 99.9% relative density with a corresponding microhardness value of 327 ± 6 HV0.5 was achieved for alloys sintered at 1300 °C and 16 MPa. Alloys sintered at 1100 °C displayed a microstructure consisting of citrus Ti-rich grains, while a duplex microstructure consisting of γ-TiAl + α2-Ti3Al lamellae, and γ-TiAl phases were observed at 1300 °C. [ABSTRACT FROM AUTHOR]

The grain size of the full lamellae TiAl-based alloy changes from ~400 μm to ~40 μm through the precipitation of metastable structures by cyclic heat treatment. Based on this, two kinds of variant selection processes—coherent metastable γ variants precipitated during the air-cooling process and αs variants precipitated during the holding at a single α phase region process—are identified to promote the formation of refined Type I and Type II coherent grain boundaries. The oxidation tests at 1000 °C for 100 h show that the formation of refined coherent grain boundaries can greatly improve oxidation resistance by inducing the continuous multi-layer protective barrier consisting of (Ti, (Nb, Ta))O2, TiN, and Al(Nb,Ta)2. This protective barrier inhibits the inward diffusion of oxygen and nitrogen.

The dual microstructure concept for gamma titanium aluminides (γ-TiAl) processed via electron beam–powder bed fusion (PBF-EB) provides a huge potential for more efficient jet turbine engines. While the concept is feasible and the mechanical properties are promising, there are still some challenges. For an industrial application, the heat treatment window has to match the conditions in industrial furnaces. This study shows how the required heat treatment window can be achieved via advanced PBF-EB technology. Through using an electron beam with 150 kV acceleration voltage, the difference in aluminum between the designed aluminum-rich and aluminum-lean regions of the part is increased. Moreover, the aluminum content within each of these regions, respectively, is more homogenous compared to the 60 kV acceleration voltage. This combination provides a heat treatment window of 25 °C, enabling the industrial application of the dual microstructure concept for γ-TiAl. [ABSTRACT FROM AUTHOR]

The processes occurring during the induction of a thermal explosion in titanium and aluminum powder mixtures are analyzed. The role of the oxide film on aluminum particles and the heating rate of samples during interaction between titanium and aluminum is considered, and various mechanisms of the oxide film destruction at temperatures near the melting point are proposed. It is shown that, depending on the heating rate of the samples, there are three possible mechanisms of formation of direct contact between titanium and aluminum: mechanical destruction of the oxide film on aluminum, the reaction of aluminum oxide with titanium, and the reaction of aluminum oxide with aluminum. Mechanical activation of the powder mixture lowers the ignition temperature by 20–30°C. As the average titanium particle size reduces from 90 to 10 m, the ignition temperature is lowered by 100°C. It is shown that a two-stage ignition mechanism is observed in a number of cases. The isothermal section of aluminum melting is followed by the stage of a slow temperature rise up to 700–800°C, after which the temperature rise rate increases tenfold. [ABSTRACT FROM AUTHOR]

Titanium aluminides (TiAl) are prominent advanced materials for aerospace and automobile industries owing to their great engineering properties conferred by ordered structures and partial covalent bonding. Of all the TiAl phases, Ti3Al and TiAl are considered to have great engineering significance and, thus, are extensively examined and developed for elevated temperature conditions. Nevertheless, one of the impediments to the wider application of TiAl and Ti3Al alloys is the deficit in the malleability at room temperature, creating difficulties during fabrication as it is sensitive to microcracks and highly susceptible to superficial defects. Sintering technologies such as cold pressing, cold isostatic pressing, hot pressing, hot isostatic pressing, combustion synthesis, and microwave sintering for producing advanced TiAl are presented. However, these processes have restrictions on the control of the microstructural properties and phase evolution, which inevitably affect the quality of the TiAl products. The novel spark plasma sintering (SPS) offers opportunities to circumvent challenges existing in the production of TiAl. An innovative hybrid spark plasma sintering technology with great potential for large-scale fabrication of operational materials with improved microstructural characteristics yielding exceptional product value and enhanced design autonomy is also presented as a robust alternative for sintering TiAl alloys. [ABSTRACT FROM AUTHOR]

γ/γ interfaces drive plastic deformation in lamellar TiAl alloys. Due to the ordering and resulting tetragonal nature of γ phase, γ/γ twin interfaces exist as different variants, some of which exhibit coherency stresses or semicoherent interface structures. While geometric parameters, such as the lamella spacing and orientation, are explored extensively in experiments, the isolation of individual influence of different interfaces in a nanolamellar microstructure remains a challenge. Herein, the range of γ/γ interface states is modeled using bilayers of the coherent γ/γTrueTwin, and the coherent or semicoherent γ/γPseudoTwin, and their deformation behavior is compared. It is shown that residual coherency stresses arise due to misfit accommodation in coherent γ/γPT specimens, which causes early preferential nucleation in one γ layer. Similarly, semicoherent specimens show preferential nucleation from misfit dislocations at the interface, which obeys Schmid's rule. In contrast, coherent γ/γTT specimens show no preferential nucleation and therefore exhibit higher strength. Thus, it is demonstrated that the presence of rotational γ/γ interfaces with misfit is responsible for localized and early plasticity, that lowers the strength of a lamellar microstructure. The interface type, which considers the coherency state, is used as a criterion for alloy microstructure design in the future. [ABSTRACT FROM AUTHOR]

In powder bed fusion additive manufacturing, the volumetric energy density EV is a commonly used parameter to quantify process energy input. However, recent results question the suitability of EV as a design parameter, as varying the contributing parameters may yield different part properties. Herein, beam current, scan velocity, and line offset in electron beam powder bed fusion (PBF‐EB) of the titanium aluminide alloy TNM–B1 are systematically varied while maintaining an overall constant EV. The samples are evaluated regarding surface morphology, relative density, microstructure, hardness, and aluminum loss due to evaporation. Moreover, the specimens are subjected to two different heat treatments to obtain fully lamellar (FL) and nearly lamellar (NLγ) microstructures, respectively. With a combination of low beam currents, low‐to‐intermediate scan velocities, and low line offsets, parts with even surfaces, relative densities above 99.9%, and homogeneous microstructures are achieved. On the other hand, especially high beam currents promote the formation of surface bulges and pronounced aluminum evaporation, resulting in inhomogeneous banded microstructures after heat treatment. The results demonstrate the importance of considering the individual parameters instead of EV in process optimization for PBF‐EB. [ABSTRACT FROM AUTHOR]

The objective of this research was to improve the forging outcome of peritectic solidifying cast titanium aluminide (TiAl) 4822 alloy (Ti-48Al-2Nb-2Cr at.%) in hot isostatic pressed and homogenised (HH) condition using cyclic induction heat treatment (CHT). This study adds to research around CHT for TiAl alloys by applying industrially relevant induction heating to conduct five heating cycles at the single αphase temperatures (1370 °C) necessary for grain refinement. Two cooling rates were explored in each cycle, air cooling (ACCHT) and controlled furnace-like cooling (FCCHT), without returning to room temperature. Samples were assessed at each stage in terms of their morphologies, lamellar grain size and content, as well as phase and dynamic recrystallised fraction, and subsequent primary and secondary compression behaviour with uniaxial isothermal compression. The FCCHT process resulted in a homogeneously refined fully lamellar microstructure, and ACCHT, in a heterogeneous microstructure consisting of lamellar and feathery γ (γf) at differing fractions across the piece, depending on the cooling rate compared with HH. The results show that CHT improved forging outcomes for both compression stages investigated, resulting in uniform compression samples with higher volumes of dynamic recrystallised material compared with the instability seen with the compression of HH material. [ABSTRACT FROM AUTHOR]

Herein, an innovative powder‐cored wire arc additive manufacturing (PC‐WAAM) process is proposed to fabricate γ‐TiAl thin‐walled intermetallic alloy. The metallography, phase composition, and mechanical properties at different thin‐wall locations are characterized. The results show that the alternatively distributed layer‐like microstructure composed of α2 (Ti3Al) and γ (TiAl) phases is obtained along the building direction. The content of α2 phase exhibits the tendency of decreasing from the bottom to top region. This unique microstructure characteristic is closely related to the typical thermal cycling history during deposition. Moreover, the tensile strength and microhardness of the top region are lower than the middle and bottom region. In general, the current PC‐WAAM technique shows promising capability of fabricating γ‐TiAl intermetallic alloy with low cost. This work becomes a valuable reference for understanding the evolution mechanism of microstructure and paves the way for the flexible and customized additive manufacturing of γ‐TiAl alloy. [ABSTRACT FROM AUTHOR]

The heat resistance of titanium with coatings based on titanium aluminides deposited by liquid-phase aluminizing followed by a high-temperature hold is studied. The effect of the duration of the hold of titanium specimens in an aluminum melt and of the duration of the high-temperature exposure of the aluminized specimens on the chemical and phase composition, structure and heat resistance of the coatings is determined. [ABSTRACT FROM AUTHOR]

Several tool wear models for machining operations have been reported in the literature. However, most of them are capable of modeling only a part of the wear curve, designed for quasi-linear curves or need to be fitted by means of differential equations. In this research, a new analytical easy-to-use wear model is proposed, taking into consideration the geometry of the cutting insert and the influence of the cutting speed and the tool-workpiece contact stress. In addition, the effect of the critical machining time, relative to the tool degradation, has also been introduced. The wear model describes completely the wear curve, from the initial rapid wear stage to the thermal-activated wear rate acceleration. The constants and parameters of the equation are determined by cutting experiments from the cutting forces and flank wear registers under a variety of technological parameters. This model has been validated for turning process on Ti48Al2Cr2Nb aluminide with uncoated carbide tool under different cutting conditions, varying the cutting speed and the geometrical position of the tool. It has been demonstrated its suitability to predict tool life, according to a defined wear criterion. [ABSTRACT FROM AUTHOR]

The development of cutting tools requires the knowledge of tribological phenomena at the tool – workpiece contact area. This knowledge is in dearth particularly for difficult-to-cut alloys like gamma titanium aluminide (gamma – TiAl alloys). Therefore, this article is an attempt to plug the gap and aid the development of cutting tools for gamma – TiAl alloys. To this end, friction, adhesion, and coating wear between AlTiSiN coated cemented carbide tool and Ti-48Al-2Cr-2Nb (Near lamellar), Ti-48Al-2Cr-2Nb (Duplex), and the most used titanium alloy of Ti-6Al-4V (alpha – beta) were experimentally derived. A Pin-on-Cylinder (PoC) tribometer with contact conditions corresponding to commercial machining conditions was used with dry, flood(EML), and two MQL lubricants. Additionally, the heat generated and partitioned between the pin and workpiece was quantified to assess the thermal exposure to the coatings. The results showed that Ti-6Al-4V had approximately 50% higher apparent friction coefficient than the Ti-48Al-2Cr-2Nb alloys. Interestingly, the friction coefficients of Ti-48Al-2Cr-2Nb alloys were nearly consistent across the entire test matrix. Notably, the change in the microstructure from near lamellar to duplex did not elicit any qualitative or quantitative change in the friction profile of Ti-48Al-2Cr-2Nb alloys. The contact pressure proved to be the statistically significant property influencing friction evolution inversely for Ti-6Al-4V alloy and directly for Ti-48Al-2Cr-2Nb alloys. The results showed higher probability of coating wear in dry conditions as opposed to the flood and MQL lubricants. [Display omitted] [ABSTRACT FROM AUTHOR]

Titanium aluminides are being explored as potential materials for the aeronautical sector. However, their application is limited by the high costs of processing and their difficulties in machining. This research evaluates the effectiveness of the minimum quantity lubrication technique (MQL) on the turning process of Ti48Al2Cr2Nb aluminide in terms of tool wear, tool life, cutting forces, surface integrity, and temperature. It was found that MQL conditions can improve the process efficiency, reducing the thermally induced wear mechanisms and enlarging the tool life compared to dry machining. Furthermore, it allows the cutting speed to be incremented, leading to lower processing times. However, MQL seems to not be effective in the reduction of the strain-hardening effect near the machined surface and, although the number of microcracks is reduced, defect-free surfaces cannot be obtained. Moreover, similar microstructural alterations as for dry cutting were detected. The best cutting conditions in terms of surface quality were assessed using the central composite face (CCF) design and surface response methodology. Optimization of the surface roughness under industrially viable cutting conditions was achieved with an average surface roughness value, Ra, of 0.29 µm (feed rate of 0.05 mm/rev, a cutting speed of 54.6 m/min and a depth of cut of 0.125 mm).

Additive manufacturing (AM), or 3D printing, has attracted increased attention in producing metallic parts with complex geometries, but it has proved difficult to prepare equiaxed fine-grain parts because the high thermal gradient in solidification commonly conduces the formation of coarse columnar grains. This work shows a solution to fine-grain titanium aluminide (TiAl) alloys by designing a high-frequency thermal cycling to control the solid-state phase transformations in layer-by-layer AM. After solidification, the specially-designed high-frequency thermal cycling can significantly refine the microstructure by repeatedly inducing the nucleation of new grains and suppressing the growth of these newborn fine grains. Therefore, even if solidification leads to coarse columnar grains, equiaxed fine-grain microstructure can still be obtained by solid-state phase transformations. The resulting TiAl alloys have fine heteromorphic grains (∼50 μm) and a fully lamellar microstructure. These fine grains contribute to good strength-ductility balance at room temperature, and their irregular shape and fully lamellar microstructure restrict the flow and distortion of grains at high temperatures, which stands a chance to significantly increase the operating temperature of TiAl parts.

Powder production by gas atomization of γ-TiAl based alloys typically yields a highly nonequilibrium material regarding the occurring phases and their microstructural appearance. In particular, the equilibration of the powder and the associated phase transformations during heating are of great importance for the subsequently applied densification techniques. The present work employs in situ high-energy X-ray diffraction to investigate how this thermodynamic equilibration manifests itself in the resulting phase distribution, the ordering behavior of the disordered α and β phase, both evidenced in the powder, and the change of the γ lattice parameters during heating of a Ti-46.3Al-2.2W-0.2B (at%) powder up to 850 °C. Complementary microstructural characterization of the gas-atomized powder and the heat-treated material condition reveals that the temperature exposure predominately affects the dendritic parts of the microstructure, especially when the α phase is transformed into γ phase with small embedded grains of α2 and βo. [ABSTRACT FROM AUTHOR]

The dynamic landscape of additive manufacturing (AM) is undergoing a transformative phase with the advent of multiple wire arc AM (MWAAM) processes. This systematic review offers an exhaustive exploration of the latest advancements and multifaceted applications of these innovative techniques within the realms of AM and welding. Prominently discussed processes encompass Bi-Metallic Wire Arc Additive Manufacturing, Twin Wire Arc Additive Manufacturing, Tandem Gas Metal Arc Welding, Twin-Wire Plasma Arc Additive, and Hybrid Wire Arc Additive Manufacturing. These techniques, instrumental in fabricating an array of materials from titanium aluminides to low-carbon steel, underscore the versatility and potential of modern AM. The application breadth spans key industries such as aerospace, naval, automotive, and energy, highlighting the ubiquity and relevance of these processes. While they promise enhanced productivity, improved material attributes, and economic efficiencies, challenges persist, including the need for meticulous parameter control, an in-depth grasp of foundational physics, and the development of sophisticated predictive models. Projecting into the future of AM, this review anticipates a harmonised integration of computational advancements with automation, positioning these MWAAM processes as pivotal in the next wave of manufacturing innovations. [ABSTRACT FROM AUTHOR]

Additive manufacturing technologies, particularly electron beam powder bed fusion (PBF‐EB/M), are becoming increasingly important for the processing of intermetallic titanium aluminides. This study presents the effects of hot isostatic pressing (HIP) and subsequent two‐step heat treatments on the microstructure and mechanical properties of the TNM‐B1 alloy (Ti–43.5Al–4Nb–1Mo–0.1B) fabricated via PBF‐EB/M. Adequate solution heat treatment temperatures allow the adjustment of fully lamellar (FL) and nearly lamellar (NL‐β) microstructures. The specimens are characterized by optical microscopy and scanning electron microscopy (SEM), X‐ray computed tomography (CT), X‐ray diffraction (XRD), and electron backscatter diffraction (EBSD). The mechanical properties at ambient temperatures are evaluated via tensile testing and subsequent fractography. While lack‐of‐fusion defects are the main causes of failure in the as‐built condition, the mechanical properties in the heat‐treated conditions are predominantly controlled by the microstructure. The highest ultimate tensile strength is achieved after HIP due to the elimination of lack‐of‐fusion defects. The results reveal challenges originating from the PBF‐EB/M process, for example, local variations in chemical composition due to aluminum evaporation, which in turn affect the microstructures after heat treatment. For designing suitable heat treatment strategies, particular attention should therefore be paid to the microstructural characteristics associated with additive manufacturing. [ABSTRACT FROM AUTHOR]

Electron beam powder bed fusion (PBF‐EB/M) has been attracting great research interest as a promising technology for additive manufacturing of titanium aluminide alloys. However, challenges often arise from the process‐induced evaporation of aluminum, which is linked to the PBF‐EB/M process parameters. This study applies different volumetric energy densities during PBF‐EB/M processing to deliberately adjust the aluminum contents in additively manufactured Ti–43.5Al–4Nb–1Mo–0.1B (TNM‐B1) samples. The specimens are subsequently subjected to hot isostatic pressing (HIP) and a two‐step heat treatment. The influence of process parameter variation and heat treatments on microstructure and defect distribution are investigated using optical and scanning electron microscopy, as well as X‐ray computed tomography (CT). Depending on the aluminum content, shifts in the phase transition temperatures can be identified via differential scanning calorimetry (DSC). It is confirmed that the microstructure after heat treatment is strongly linked to the PBF‐EB/M parameters and the associated aluminum evaporation. The feasibility of producing locally adapted microstructures within one component through process parameter variation and subsequent heat treatment can be demonstrated. Thus, fully lamellar and nearly lamellar microstructures in two adjacent component areas can be adjusted, respectively. [ABSTRACT FROM AUTHOR]

Young's modulus and hardness of the constituent phases of β-Ti (bcc or B2), in equilibrium with α 2 -Ti 3 Al (D0 19) and γ-TiAl (L1 0) phases in Ti-Al-Cr ternary alloys were quantitatively evaluated in terms of the chemical composition analysis and nano-indentation method, in order to identify the Cr concentration dependence on the mechanical properties of the β phase. An alloy with a nominal composition of Ti-43Al-3Cr (at.%) decomposes into the three phases of β, α 2 , and γ by equilibrium heat treatment at 1373 K, with chemical composition of Ti-37.2Al-5.2Cr, Ti-38.9Al-2.2Cr, and Ti-47.4Al-1.4Cr, respectively. The β phase shows a Young's modulus of 141 ± 5 GPa, smaller and less orientation dependent than the other two phases of α 2 (174 ± 9 GPa) and γ phases (164 ± 15 GPa). In contrast, the β phase has a hardness of 5.9 ± 0.3 GPa, slightly softer than the α 2 phase (6.4 ± 0.8 GPa) but much harder than the γ phase (3.7 ± 0.6 GPa). The alloys Ti-44Al-4Cr and Ti-45Al-6Cr consist of two phases of β and γ phases, and the chemical composition of the β phase in these two alloys is Ti-36.5 Al-8.5 Cr and Ti-36.3 Al-13.9 Cr, respectively, with nearly the same Al concentration. The Young's modulus and hardness of the β phase with the latter composition become 158 GPa and 6.7 GPa, respectively, with increasing Cr content. These results found that the effect of solid solution Cr on the Young's modulus for β phase is relatively weak, and that on the hardness is strong, in comparison with that for the other two phases. [Display omitted] • β-Ti phase shows lower Young's modulus, E , than α 2 -Ti 3 Al and γ-TiAl phases. • β and α 2 phases show higher hardness, H , than γ phase. • E increases with the addition of Cr in the three phases. • H increases in β and α 2 phases, and it remains constant in γ phase with Cr content. [ABSTRACT FROM AUTHOR]

To regulate the microstructure of directionally solidified TiAl alloy and improve its service temperature and high-temperature mechanical properties, the large-size single crystal Ti-44.5Al-3Nb-0.6Si-0.2C alloy with full lamellar structure prepared by electromagnetic confinement directional solidification was heat-treated in the α single-phase region. The results show that this alloy has high stability and no recrystallization occurs at 1340 °C for 30 min. The (α 2 +γ) lamellar structure formed during the subsequent cooling process is consistent with the orientation of the original as-cast state, and the refinement effect is very significant. The thickness of the α 2 and the γ phases is 1/3 and 1/10 of the original structure, respectively. The dislocation strengthening and the interface strengthening are enhanced with the increase of the dislocation density and the number of α 2 /γ phase boundaries in the refined lamellar structure after heat treatment, thus resulting in a substantial increase of compressive strength at 1000 °C. The corresponding compressive peak strength at 1000 °C is 2.6 times higher than that of the as-cast alloy, reaching 709 MPa. This exceeds almost all the TiAl alloys under the same conditions reported so far. This research is expected to increase the service temperature of TiAl alloy to 1000 °C, thereby replacing more Ni-based superalloy components and promoting the lightweight development of aero engines. • This alloy has high stability and no recrystallization in the α single-phase region. • The refined lamellar structure can be obtained by air cooling from the α phase region. • The refined lamellar structure makes the high-temperature strength much higher. • Interface strengthening and dislocation strengthening have a great contribution to strength. [ABSTRACT FROM AUTHOR]

The susceptibility of titanium aluminides (TiAl) to environmental embrittlement is one of the factors limiting the use of this class of intermetallic alloys. After being exposed to air at high temperatures, the ductility of the material at room temperature is significantly reduced or even completely lost. In the present work the influence of near surface grain refinement on the example of the β-stabilised TNM alloy on the embrittlement behaviour after exposure for 2 h at 700 °C in air is presented and discussed. The main characteristic of the environmental embrittlement is that cracks during tensile tests at room temperature appear on the surface and lead to rapid failure. One of the reasons given in literature for this behaviour is that high tensile stresses form at the sample edge by exposure. Grain refinement of the surface region with a depth of approximately 350 μm displaces crack initiation during tensile testing well below the surface after exposure. The environmental embrittlement phenomenon after short-term exposure does, thus, not occur in this layer-like structure. Various reasons for this behaviour, which include delayed crack formation, stress relaxation during loading and cooling after loading as well as supporting effects, but also the limitations of the treatment method, are discussed in the work. • Environmental embrittlement of TiAl alloys can be reduced by a fine-grained surface. • Reasons for this behaviour, like stress relaxation, are identified and discussed. • Fine grained surface leads to high strain hardening rate of coarse-grained interior. • Origin of the embrittlement lies in the area close to the surface (max. depth 2 μm). • Removal of the area of visible microstructural changes restores ductility. [ABSTRACT FROM AUTHOR]

Titanium aluminides (TiAl) are distinguished by their exceptional strength-to-weight ratio, making them ideal for aerospace and medical applications. Notably, TiAl alloys offer a unique combination of high-temperature resistance and corrosion resilience, contributing to their growing prominence in advanced engineering and biomedical fields. Although initially developed for aerospace applications, TiAl alloys have demonstrated promising potential as implant materials over time. Hence, this research focuses on producing γ-TiAl alloy through electron beam powder bed fusion (EB-PBF) technology, utilising a powder with a composition of Ti-48Al-2Cr-2Nb. For comparative purposes, the corrosion characteristics of Ti6Al4V produced via EB-PBF were also evaluated under identical conditions. The findings indicate that the EB-PBF γ-TiAl exhibits exceptional resistance to corrosion. This is supported by the significantly high polarisation resistance and corrosion potential values, as well as the notably low corrosion current value. However, based on the analysis of the polarisation and impedance curves, it can be observed that the γ-TiAl sample displayed a less protective passive film formation. This occurrence can be attributed to the presence of aluminium ions within the passive layer, resulting in the formation of unstable oxides. As a consequence, it can be inferred that γ-TiAl exhibits inferior resistance to pitting corrosion when compared to Ti6Al4V alloy. The point defect model and Mott-Schottky test further revealed that the γ-TiAl alloy exhibited increased oxygen vacancies. Additionally, the presence of aluminium ions as impurities or dopants led to their substitution for titanium ions, creating cationic vacancies within the passive film. The accumulation of excessive cation vacancies ultimately led to the initiation of pitting corrosion. • Electrochemical behaviour of γ-TiAl produced by the electron beam powder bed fusion process is investigated. • The corrosion potential and current density of the γ-TiAl intermetallic alloy are comparable to the Ti6Al4V sample. • γ-TiAl alloy exhibits excellent corrosion resistance when exposed to 0.9 % NaCl solutions. • The concentration of Al ions released from the γ-TiAl was higher than Ti6Al4V. • Higher Al content in γ-TiAl sample increases the density of cationic vacancies within the passive films. [ABSTRACT FROM AUTHOR]

The purpose of this study is to determine if forged TiAl alloys are worth using for small parts such as jet engine turbine blades. As part of this goal, this study investigated ways to improve the impact resistance of forged TiAl alloys and compared them to cast TiAl alloys. The effects of additive elements and microstructure on the impact resistance of forged ternary TiAl alloys of 43.5 at. % Al were evaluated using the Charpy impact test on specimens heated to 500 °C prior to testing. The impact resistance of the forged alloys improved with the addition of Cr, V, and Mn and deteriorated with the addition of Nb. The impact resistance of the microstructure containing a β-phase, a common microstructure in forged TiAl alloys, was significantly lower. The fully lamellar structure obtained at the expense of forgeability showed much higher impact resistance than this. However, even the best impact resistance of the forged alloys was significantly inferior to that of cast ternary alloys of 46.5 at. % Al prepared with the same additive content. Combined with the high cost and low high-temperature strength of the forged TiAl alloys, it is concluded that it is pointless to use forged TiAl alloys for small parts that can be made via casting.

In this work, the stability of the microstructure of the experimentally obtained two-phase (O + B2) alloy of the Ti–25Al–25Nb (at.%) system were studied during thermal cycling in a hydrogen atmosphere. It was found that the two-phase structure (O + B2) of the alloy of the Ti–Al–Nb system shows high thermodynamic stability. In this case, phase transformations of secondary phases (α2, AlNb2) are observed in the microstructure of the alloy, the volumetric content of which at all stages of testing does not exceed 2%. Thus, after the first cycle of high-temperature exposure, single inclusions of the α2 phase precipitate, while in the areas enriched in Ti and Al, due to the redistribution of Nb, a new colony of the α2 phase is observed. After five test cycles, it was found that large accumulations of the α2 colony, due to the α2 → B2 phase transformations, form new micron-sized grains of the B2 phase. A volumetric accumulation of nanosized precipitates of the AlNb2 phase was found near the triple joints of the grain boundaries of the B2 phase after 10 cycles of thermal exposure, which is caused by the supersaturation of B2 grains with niobium.

A laser powder bed fusion process operating at elevated temperatures is introduced capable of fabricating crack-free and dense intermetallic titanium aluminide alloy specimens as well as demonstrator components using a base plate heating up to 900 °C and a unique heating system of the uppermost powder bed layer up to 1200 °C. Two so-called 4th generation alloys, TNM and TNM+, were used for this study. The microstructure and its evolution during subsequent heat treatments were investigated and explained by employing scanning electron microscopy, hardness testing, X-ray diffraction, differential scanning calorimetry and thermodynamic equilibrium calculation. Selected specimens were subjected to creep tests at 750 °C. The microstructures after processing consist of extraordinarily fine lamellar γ-TiAl/α2-Ti3Al-colonies with globular γ and βo-TiAl grains for both the TNM and TNM+ alloy, exhibiting a microstructure gradient from the last consolidated powder layer down to the starting layer due to cellular reaction, which increases the amount of globular γ and βo at the boundaries of the γ/α2-colonies. During annealing in proximity to the γ-solvus temperature, banded microstructures might form, as the α-grain size is only partially controlled by heterogeneously distributed γ/β-phase, which stems from the process-related Al loss. Additionally, the occurrence of thermally-induced porosity is investigated. Optimizing the microstructure to a homogenized, almost fully lamellar microstructure, involved annealing in the β-single phase field region and led to improved creep properties. Finally, TNM demonstrator components with complex geometries, such as aero engine blades and turbocharger turbine wheels, are fabricated by employing the novel laser powder bed fusion process. [ABSTRACT FROM AUTHOR]

Transition metal trialuminides of the Al3X type of groups 4 and 5 of the periodic system have reduced density, high melting points, and corrosion resistance. Aluminides with a cubic lattice of the Al3Sc type can be used as a nucleating phase for aluminum alloys. However, low plasticity and a tetragonal lattice limit their application. In this work, we stabilized the metastable cubic lattice of Al3X-type aluminides by replacing aluminum with copper. The conditions for the formation of L12 metastable aluminides in the Al–Cu–TM (TM: Ti, Zr, Hf) alloys were studied using a wide range of copper concentrations. A high concentration of copper (hypereutectic alloys) is the one of the necessary conditions for the formation of (Al1−xCux)3Ti, (Al1−xCux)3Zr, (Al1−xCux)3Hf aluminides. With an increase in the copper concentration, the number of metastable aluminides sharply increased. The process of their formation strongly depended on the sequence of dissolution of the corresponding components in the melts. The low volume fraction of precipitated titanium aluminides was the result of insufficient supersaturation of α-Al with titanium (at the peritectic temperature) compared to that for alloys with zirconium and hafnium. Under identical synthesis conditions in the crystal lattice of metastable aluminides formed in experimental Al–Cu–Ti, Al–Cu–Zr, Al–Cu–Hf alloys, copper was found to substitute up to 8, 10, and 13 at.% of aluminum, respectively. The crystallographic and dimensional similarities of the lattices in metastable transition metal aluminides and in α-Al suggest their usefulness as modifying additions in aluminum-based alloys. [ABSTRACT FROM AUTHOR]

Intermetallic alloys such as titanium aluminides (TiAl) are potential materials for aerospace applications at elevated temperatures. TiAl intermetallics have low weight and improved efficiency under aggressive environments. However, there is limited information about wear behavior of these alloys and their microstructure. The present work aims to study the influence of the microstructure in the tribological behavior of TiAl intermetallic alloy (45Al-2Mn-2Nb(at%)-0.8 vol%TiB2). Wear tests were performed on samples manufactured by centrifugal casting (CC) and hot isostatic pressure (HIP). Reciprocating sliding wear test was carried out for TiAl, it was combined with different loads and frequencies. Wear tracks were analyzed through opto-digital microscopy and electron microscopy (SEM). The results obtained reveal that CC intermetallics present the lowest volume wear lost, approximately 20% less than HIP intermetallics. This good behavior could be related to the high hardness material, associated with the main microstructure where CC intermetallic has nearly lamellar microstructure and HIP intermetallics present duplex microstructure. [ABSTRACT FROM AUTHOR]

The deformation behavior in the isothermal compression of Ti-46.5Al–2Nb–2Cr (at. %) including flow stress and microstructure evolution at the deformation temperatures ranging from 1373 to 1533 K and strain rates from 0.001 to 1 s−1 were investigated. The phenomenological-based model was established by describing the variation of the strain hardening exponent with the increasing of strain. The strain rate sensitivity exponent ranging from 0.065 to 0.449 indicated the transition of deformation mechanism from dislocation creep to grain boundary sliding, and the model by considering the effect of the processing parameters on the strain rate sensitivity was presented. The effect of the processing parameters on the apparent activation energy for deformation was analyzed. Furthermore, the novel constitutive model coupling with the strain hardening exponent and strain rate sensitivity exponent in the deformation was put forward and applied to predict the deformation behavior of Ti-46.5Al–2Nb–2Cr.

The objective of this research was to improve the forging outcome of peritectic solidifying cast titanium aluminide (TiAl) 4822 alloy (Ti-48Al-2Nb-2Cr at.%) in hot isostatic pressed and homogenised (HH) condition using cyclic induction heat treatment (CHT). This study adds to research around CHT for TiAl alloys by applying industrially relevant induction heating to conduct five heating cycles at the single αphase temperatures (1370 °C) necessary for grain refinement. Two cooling rates were explored in each cycle, air cooling (ACCHT) and controlled furnace-like cooling (FCCHT), without returning to room temperature. Samples were assessed at each stage in terms of their morphologies, lamellar grain size and content, as well as phase and dynamic recrystallised fraction, and subsequent primary and secondary compression behaviour with uniaxial isothermal compression. The FCCHT process resulted in a homogeneously refined fully lamellar microstructure, and ACCHT, in a heterogeneous microstructure consisting of lamellar and feathery γ (γf) at differing fractions across the piece, depending on the cooling rate compared with HH. The results show that CHT improved forging outcomes for both compression stages investigated, resulting in uniform compression samples with higher volumes of dynamic recrystallised material compared with the instability seen with the compression of HH material.