Ti-rich Precipitates Research Articles

Relations of magnetic and electrochemical anti-corrosion properties of (Zr, Ti)-doped NdCeFeB magnets with Ti content

Zr and Ti were co-doped into NdCeFeB sintered magnets to improve the magnetic and electrochemical anti-corrosion properties. Both performance are found closely associated with Ti content. At 0.15 wt%Ti, the sample shows higher coercivity without energy product loss compared to the Ti-free sample and other Ti additions, due to the matrix-phases refinement and optimized distribution of RE-rich phases. For this sample, its corrosion current density and charge transfer resistance are 1.94 μA/cm2 and 1734 Ω•cm2 in NaCl solution respectively, which exhibits obviously improved corrosion resistance in comparison with the Ti-free magnet. The charge transfer resistance has been increased by 45.6 %. The apparently improved corrosion resistance is mainly attributed to the decreased amount of active reaction channels and the enhanced protective effect of TiO2, arising from the increment of Ti-rich precipitates. When the content of Ti dopant exceeds 0.5 wt%, the beneficial effects of Ti are overshadowed by the harmful effect of the density reduction on anti-corrosion performance, and the charge transfer resistance decreased with further increasing the dopant content. The new findings provide a theoretical basis for improving physicochemical properties of NdCeFeB magnet.

The effect of cobalt alloying on the phase transformation kinetics of Ni-Ti alloys

This study investigates the influence of cobalt (Co) alloying addition and heat treatment temperature on the phase transformation behaviour controlling the superelasticity and shape memory effect (SME) of Nickel-Titanium (Ni-Ti) alloys, commonly known as nitinol. The microstructural evolution upon heat treatment conducted at a temperature ranging from 440 to 560 °C was thoroughly analyzed via Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), and Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS). Increase in heat treatment temperatures from 470 °C up to 530 °C led to the dissolution of particles present in as-received (cold-worked) condition. It was determined that Co addition into the Ni-Ti alloy system resulted in a change in the nucleation and growth kinetics of Ti-rich precipitates, leading to the formation of larger and fewer particles during processing. Both binary and ternary alloys showed a decrease in austenite finish temperature (Af) with increasing heat treatment temperatures, however, the rate of decrease was found to be higher for Co containing ternary alloys. This is linked with faster structural relaxation when Co is present and evidenced by lattice size variation during heat treatment. It is highlighted that heat treatment methodology needs to be tailored to the specific alloy composition for controlling superelasticity and SME via alloy design.

In-situ synthesis of TiN and its effects on Fe-12Cr-6Al in laser powder bed fusion

This study examines the feasibility of in-situ synthesis of various nitride and oxide precipitates and their impact on Fe-12Cr-6Al alloy characteristics using an N2 reactive gas atmosphere and Ti addition during the L-PBF process. This study focused on elucidating the effects of adding Ti on the Fe-12Cr-6Al's melt pool dynamics, microstructure, precipitate characteristics, oxygen/nitrogen content variation, and mechanical properties. Without Ti, the resulting melt pools exhibited a shallow and wide morphology, contrasting with the formation of compact and deeper melt pools in the presence with Ti. Furthermore, Ti-based nitrides yielded a discernible enhancement in grain refinement compared to Al-based nitrides. In-situ Al2O3, AlN, and AlN-O nano precipitates were synthesized within the Fe-12Cr-6Al matrix with the nitrogen process gas. However, adding Ti transformed the nanoparticles, resulting in TiN, TiAl-N, and Al2O3@TiN. The addition of Ti increased the oxygen content from 0.0051 to 0.0315 wt.% and the nitrogen content from 0.02 to 0.08 wt.%. In-situ synthesis of Ti-rich precipitates and the solid solution effect of Ti led to significant mechanical property enhancement, including a yield strength (YS) of ∼109 MPa, ultimate tensile strength (UTS) of ∼200 MPa, a total elongation (TE) of ∼7.4%, and a Vickers hardness (HV) of ∼47. This study offers compelling and thorough evidence regarding the in-situ synthesis of diverse nitride and oxide nano-precipitates. It explores how the addition of Ti to the FeCrAl alloy alters the types and shapes of nitride and oxide nano-precipitates and assesses the impact of these precipitates on the properties of the Fe-12Cr-6Al alloy.

Inhibition of Ti-rich precipitates and improvement of the irradiation resistance in V-4Cr-4Ti by adding La element

Four kinds of V-4Cr-4Ti-xLa (nominal composition x = 0, 0.1, 0.5, 1.0 wt.%) alloys with different La contents were prepared by vacuum arc melting. Three of them (x = 0, 0.1, 1.0 wt.%) were selected for single He+ (2000 appm for peak concentration) irradiation and sequential He+/V2+ (10 dpa for peak damage) irradiation at 550 °C. The results showed that the addition of La element could refine the grains by forming the second phase La2O3 particles. Moreover, the addition of La element reduced the sum of impurity elements concentration in the alloy, which inhibited the formation of Ti-rich precipitates and affected the vacancy concentration, thus affecting the evolution of He bubbles under different irradiation types. In addition, the V-4Cr-4Ti-1.0La alloy had a lower irradiation hardening after sequential He+/V2+ irradiation, which might be related to the removal of impurity elements. This work provided a reference for the performance optimization of vanadium alloy for fusion reactors.

Non-negligible role of gradient porous structure in superelasticity deterioration and improvement of NiTi shape memory alloys

Bone-mimicking gradient porous NiTi shape memory alloys (SMAs) are promising for orthopedic implants due to their distinctive superelastic functional properties. However, premature plastic deformation in weak areas such as thinner struts, nodes, and sharp corners severely deteriorates the superelasticity of gradient porous NiTi SMAs. In this work, we prepared gradient porous NiTi SMAs with a porosity of 50% by additive manufacturing (AM) and achieved a remarkable improvement of superelasticity by a simple solution treatment regime. After solution treatment, phase transformation temperatures dropped significantly, the dislocation density decreased, and partial intergranular Ti-rich precipitates were transferred into the grain. Compared to as-built samples, the strain recovery rate of solution-treated samples was nearly doubled at a pre-strain of 6% (up to 90%), and all obtained a stable recoverable strain of more than 4%. The remarkable superelasticity improvement was attributed to lower phase transformation temperatures, fewer dislocations, and the synergistic strengthening effect of intragranular multi-scale Ti-Ni precipitates. Notably, the gradient porous structure played a non-negligible role in both superelasticity deterioration and improvement. The microstructure evolution of the solution-treated central strut after constant 10 cycles and the origin of the stable superelastic response of gradient porous NiTi SMAs were revealed. This work provides an accessible strategy for improving the superelastic performance of gradient porous NiTi SMAs and proposes a key strategy for achieving such high-performance architectured materials.

Effect of Ti-rich precipitation on mechanical properties of vanadium alloy after aging treatment

V-4Cr-4Ti alloys currently constitute advanced candidate materials for the blanket of future fusion reactors. Precipitations occur in the working environment of V-4Cr-4Ti alloy and affect the stability of the alloy. The working environment was simulated by aging at 773–973 K and the formation of precipitation and its effect on mechanical properties was studied. The result showed that Ti-rich precipitates formed in the alloy when aged. The precipitates were lath-like and lower in size and density when aged at 773 K. And lath-like precipitates with larger size and density formed at 873 K. While polygon precipitates formed at 973 K with a size and density lower than 773 K and 873 K. The composition analysis indicates that the three precipitates formed during aging consist of Ti(CN). The crystal structures of the precipitates are face-centered cubic (FCC). The interface between the matrix and the precipitate can be semi-coherent. Both lath-like and polygon precipitates increase the hardness and strength of the alloy. Among these, the comprehensive mechanical properties due to higher strength and elongation obtained in alloys with polygon precipitates. The formation mechanism of precipitation was analyzed from the atomic point of view.

Effect of titanium content on solidification structure of ferritic stainless steel gas-tungsten and gas-metal arc welds

Ferritic stainless steel is utilized to fabricate automotive exhaust systems using a ferritic weld metal. Ductility of the weld metal is higher if its microstructure contains a significant proportion of equiaxed grains. The formation of equiaxed (rather than columnar) grains is favoured by a higher titanium weld metal content. In this study, the Ti content of ferritic stainless steel weld metal was changed by using Ti-free (Type 436) and Ti-containing (441) ferritic stainless steel as base metals. The metal-cored welding consumable contained 0.4% Ti. Gas-tungsten arc welding and gas-metal arc welding processes were compared. The weld metal Ti content ranged from zero to 0.5% Ti, as determined from scanning electron microscopy supplemented by inductively coupled plasma optical emission spectroscopy. Cross-sections of the weld beads were subjected to point counting (to estimate the fraction of equiaxed grains) and image analysis (to estimate the average grain size). Point counting proved to be more reliable. The fraction of equiaxed grains was sensitive to the Ti content, but not to the welding process. Below 0.4% Ti, the fraction of equiaxed grains gradually increased with an increase in the weld metal Ti content; above 0.4% Ti, the fraction of equiaxed grains rapidly increased with increasing Ti content. The transition in behaviour at 0.4% Ti corresponded to a Ti content at which Ti-rich precipitates became stable at the estimated liquidus temperature of the weld metal.

Revealing morphology rules of MX precipitates in Ti-V-Nb multi-microalloyed steels

Despite a large number of studies relevant to MX (M = Ti, V, Nb; X = C, N) precipitation in microalloyed steels, the evolution rules of the precipitate morphology remain unclear. In this work, the precipitation behavior and morphological characteristics of MX precipitates in deformed Ti-V-Nb multi-microalloyed steels under continuous cooling were revealed through integrating transmission electron microscopy and theoretical models. The experimental results demonstrate that the precipitates are mainly Ti-rich cuboidal multi-component precipitates and irregular compound precipitates formed in austenite, and fine spherical V8C7 precipitates formed in ferrite. For the first time, the L parameter model that evaluates the shape of MX precipitates has been introduced into microalloyed steels, together with the validating experiments. In austenite, as the L increases, precipitates tend to become cuboidal under equilibrium conditions while rod-like elongating along their 〈100〉 orientation under deformation conditions; in ferrite, as the L increases, precipitates tend to be disk-like under equilibrium conditions while thin elliptical cylindrical extending along their 〈110〉 orientation on the habit plane under deformation conditions. The evolution rules of precipitate morphology revealed in this work provide insights in controlling precipitates morphology to develop high-performance microalloyed steels.

Effect of yttrium content on microstructure and irradiation behavior of V-4Cr-4Ti-xY alloys

V-4Cr-4Ti-xY alloys with different yttrium (Y) contents (x = 0, 0.1, 1 wt. %) were prepared and irradiated with Fe2+ at 550 ℃ to the peak damage dose of 35 dpa (displacement per atom). The microstructure and hardness of the alloys before and after irradiation were obtained with transmission electron microscopy (TEM), scanning electron microscopy (SEM) and nano-indentation test. With the increase of Y contents, the grain size decreased monotonously, and the formation of needle-like Ti-rich precipitates was suppressed. After irradiation, voids were not observed in Y added alloys but in the V-4Cr-4Ti alloy, showing that the addition of Y could inhibit the formation of voids and irradiation-induced swelling. Dislocation loops and obvious irradiation hardening were observed in all V-4Cr-4Ti-xY alloys, and the size of the dislocation loops and the irradiation hardness increment decreased with the increase of the Y content. The irradiation-induced growth of Ti-rich precipitates was observed, which may be an important factor contributing to the irradiation hardening besides the dislocation loops and voids. The possible mechanism of the effect of the Y element on the irradiation behavior was discussed. Among the three Y contents, V-4Cr-4Ti-1Y alloy exhibits the best performance in the suppression of the formation of Ti-rich precipitates and irradiation hardening.

Characterization of the nature and morphology of coarse precipitation in various oxide dispersion strengthened steels

Oxide Dispersion Strengthened (ODS) steels are candidate materials for both fission and fusion nuclear reactors. In this study, the microstructure of ferritic (Fe-14Cr-1W) and ferritic / martensitic (Fe-9Cr-1W) ODS steels has been characterized after two different processing routes: Hot Extrusion (HE) and Hot Isostatic Pressing (HIP). Transmission Kikuchi Diffraction (TKD) revealed the presence of Ti-rich precipitates on every specimen. They are identified by X-Ray Diffraction (XRD) as Ti(C,N) and Ti-O (Ti2O3 or TiO2). Intergranular M7C3 and M23C6 have been observed on most Fe-14Cr ODS steels except one, where no Cr-carbides have been found. In Fe-9Cr ODS, intergranular Cr-rich M23C6 carbides have been found. The lack of M7C3 on Fe-9Cr ODS is possibly linked to the matrix phase transformation, not occurring in the Fe-14Cr ODS. Cr-carbides display highly elongated shapes for the Fe-14Cr HE specimens that could be detrimental to the mechanical behavior of the material.

Compositional modulation is driven by aliovalent doping in n-type TiCoSb based half-Heuslers for tuning thermoelectric transport

The ternary intermetallic TiCoSb based half-Heusler (HH) alloys are prominent material exhibiting good p-type thermoelectric (TE) performance. In this work, we studied the implication of V and Nb as n-type aliovalent dopants on Ti crystallographic site of semiconducting TiCoSb based HH alloys for attaining higher TE performance in n-type counterparts. The carrier concentration optimization between semiconducting (Ti1−xVxCoSb) and semi-metallic regime (Ti1−xNbxCoSb) had resulted in maximum TE figure-of-merit (ZT) of 0.22 and 0.52 at 873 K for optimized Ti0.85V0.15CoSb and Ti0.85Nb0.15CoSb HH compositions, respectively. These substitutional alloys were synthesized using arc-melting and consolidated using spark plasma sintering, which resulted in biphasic microstructure with in-situ phase segregation of heterogeneously distributed Ti-rich precipitates at all length scales within the HH matrix, are examined by microstructural analysis using X-ray diffraction and electron microscopy. Interestingly, higher power factor and simultaneous reduction of thermal conductivity is observed in both the doping as a result of optimal carrier concentration and enhanced phonon scattering. However, Nb-doped alloys exhibit higher carrier mobility and more significant lattice thermal conductivity reduction, thus establishing n-type Ti1−xNbxCoSb HH alloys as an equally promising counterpart of p-type TiCoSb for mid-temperature TE power generation.

Response of microstructure and hardening to deuterium ion irradiation inV-4Cr-4Ti-1.8Y-0.4Ti3SiC2 and V-4Cr-4Ti alloy

Abstract Deuterium implantation with 60 keV was carried out in V-4Cr-4Ti-1.8Y-0.4Ti3SiC2 alloy prepared via MA-HIP method and V-4Cr-4Ti alloys prepared by VAR. Dispersion particles, Ti-rich precipitates and irradiation-induced dislocation loops are studied using TEM. Micro-hardness and radiation-hardening are measured using Nano-indenter. The dissolving of additional Ti3SiC2 particles and the formation of Y2O3, (Ti, Si) C and Y2 (Ti, Si) 2O7 particles are observed in V-4Cr-4Ti-1.8Y-0.4Ti3SiC2 alloy. Ti-rich precipitates in both alloys prefer to grow along M direction, where the precipitates/matrix interfaces have minimum distortion energy. Ti-rich precipitates in V-4Cr-4Ti-1.8Y-0.4Ti3SiC2 alloy is much smaller. Although the mean size and density of dislocation loops is similar in both kinds of alloy, V-4Cr-4Ti-1.8Y-0.4Ti3SiC2 alloy has a much lower radiation-hardening. TEM results show that Ti-rich precipitates in V-4Cr-4Ti-1.8Y-0.4Ti3SiC2 alloy grow up after irradiation, while the size of precipitates decrease in V-4Cr-4Ti alloy. The calculation results based on Orowan mechanism show that the size evolution of Ti-rich precipitates is the dominant factor for the different behavior of two alloy on radiation-hardening.

Achieving exceptional wear resistance in a compositionally complex alloy via tuning the interfacial structure and chemistry

Titanium alloys have been widely used for medical devices and structural applications. However, conventional titanium alloys often suffer from low resistance to wear, particularly at elevated temperatures. Herein, an equiatomic TiMoNb compositionally complex alloy (CCA) is shown to exhibit wear resistance comparable to alumina at room temperature (RT). Even at 600 °C, the alloy still shows an extremely low wear rate of the order of 10−6 mm3/(N·m). The remarkable wear resistance is achieved via tuning the interfacial structure and chemistry in TiMoNb CCA, including nanostructuring, titanium segregation at the grain boundaries, and the formation of a high density of nanoscale coherent Ti-rich precipitates with cube-on-cube orientation relationship with the ultrafine-grained matrix. The present results provide significant insights into the design of novel alloys for service in harsh environments.

Microstructure Characterization in Dissimilar TIG Welds of Inconel Alloy 718 and High Strength Tensile Steel

Nickel based super alloy Inconel 718 is widely used in aerospace and power generation industries. The dissimilar joining of high strength tensile steel to Inconel 718 was joined using TIG welding. The welding current and travel speed parameters were varied to identify the suitable welding conditions for achieving highest joint strength. Microstructural characterization of the weldments were evaluated by using optical, scanning electron microscope and energy dispersive spectroscopy analysis. The fracture surfaces of the tensile tested joints were investigated under scanning electron microscope to reveal the mode of fracture and its influence on the performance of the joints. Microhardness and tensile tests were conducted to evaluate mechanical properties of the joints. The microstructure evolution revealed that the formation of precipitates at the fusion boundary between the weld zone and Inconel 718 alloy. The hardness of the fusion boundary area id higher than the base metal and fusion zone on Inconel 718 side, whereas the highest hardness obtained in heat affected zone on high tensile strength steel. The strength of the joints were failed in the weld zone along the deposition of the filler metal, which strength is similar to the joint strength. The elemental line scan analysis confirmed the formation of Nb and Ti rich precipitates in weld zone and along the fusion boundary of Inconel alloy.

Characterization of interface irradiation damage in Ti-clad V-4Cr-4Ti composite material

The development of electrically insulating coatings is extremely important for the lithium/vanadium (Li/V) blanket of the fusion reactor. However, Li/V cladding materials suffer many problems such as tritiumpermeation and material corrosion. Thus, it is very important to find suitable insulating, tritium-resistant and corrosion-resistant coatings. So, the " V-alloy/Ti/AlN” bilayer coating was proposed by our group in previous study for the first time. In this paper, the evolution of the hardness, irradiation defects and microstructure of the Ti-clad V-4Cr-4Ti composite material after Fe<sup>10+</sup> implantation are studied by transmission electron microscopy (TEM) and nanoindentation. According to the characteristics of the composition and microstructure, V-4Cr-4Ti/Ti composite material can be divided into four zones: V-4Cr-4Ti matrix, interface I (the interface near V-4Cr-4Ti matrix), interface II (the interface near Ti matrix), and Ti matrix. The nanoindentation results show that radiation hardening occurs in all regions during irradiation. The radiation hardening in the interface is lower than in the V-4Cr-4Ti and Ti matrix. Thus, the interface of heterogeneous material exhibits fine resistance to radiation hardening. The experimental values of hardness are much higher than the values calculated by the dispersed barrier hardening model. One reason for the discrepancy is that the theoretical values are calculated under the hypothesis of the uniform loop distribution. Actually, a large number of dislocation loops accumulate and tangle with each other in the samples. In addition, the formation of the precipitates is also one of the key factors. The TEM results show that the irradiation defects in the interface are low in density, large in size, and uniform in distribution. As a contrast, high density, small size and twisted dislocation loops are observed in irradiated V-4Cr-4Ti and Ti matrix. These results indicate that the interface can play a critical role in the resistance to irradiation damage. Few tiny Ti-rich precipitates appear in the V-4Cr-4Ti matrix, while there are large quantities of Ti precipitates in the interface after irradiation. Moreover, the number and size of precipitates in the interface I are larger than those in the interface II due to the formation of a few V-rich precipitates in the interface I. The formation of precipitations changes the proportion of V/Ti, which leads to the transformation from <i>β</i>-Ti to <i>α</i>-Ti in the interface.

Precipitation Behaviors of a New Antibacterial Maraging Stainless Steel for Medical Instruments

A new antibacterial maraging stainless steel with high hardness and good antibacterial property has been developed. The hardness of the new maraging stainless steel with a cold rolling deformation of 85 pct reaches the peak about 58.5 HRC after aging heat treatment, which is mainly due to the ɛ-Cu and Ni-, Al-, Ti-rich precipitates. Reverted austenite transformed from the martensite is responsible for the decrease of hardness when aging at higher temperature. Three-dimensional atom probe (3DAP) and transmission electric microscope (TEM) were used to investigate the precipitates formed in the martensite matrix after aging at 713 K for 4 hours. The ɛ-Cu and Ni-, Al-, Ti-rich precipitates distribute uniformly in the martensite matrix, and the Ni-, Al-, Ti-rich precipitates are nucleated on the Cu-rich precipitates. Because of the ɛ-Cu precipitates, the new maraging stainless steel possesses an excellent antibacterial property with the rate about 95.08 pct, which has a wide application prospect on scalpels and surgical needles.

Microstructure and mechanical performance of welded joint between a novel heat-resistant steel and Inconel 617 weld metal

In the present study, the microstructure and mechanical performance of a tungsten inert gas welded joint between a novel heat-resistant austenitic steel and Inconel 617 weld metal were examined. Migrated grain boundaries were discovered more frequently in the lower portion of the weld metal that solidifies in austenite type. Ti-rich precipitates were observed in weld metal and Cr-rich and Nb-rich precipitates were observed in base metal. The fusion boundary area had the lowest impact toughness due to the large non-homogeneity of the microstructure. Microhardness profiles of the joint were obtained and the backing passes were found to produce the highest microhardness values, which was caused by the grain refinement effect. Ductile failure with slipping separation occurred in those joints ruptured after tensile tests at both room temperature and 923 K. In addition, multiscale precipitates in the joint after high-temperature tensile tests were inspected, where it was found that nanoscale particles contributed to the high-temperature resistance of the joint. Furthermore, microhardness changes in the joint after tensile tests were analysed according to the precipitation and strain-hardening mechanism.

Impact of iron composition on the properties of an additively manufactured solid solution strengthened nickel base alloy

The impact of changes in Fe content from 1 wt% to 4 wt% on the properties of additively manufactured (AM) Inconel® 625 fabricated using laser-based directed energy deposition (DED) is investigated in both the as deposited and post processed hot isostatically pressed (HIP) conditions. While similar solidification structures and microhardness values are observed, the low Fe content build displayed higher yield (520 MPa ± 12 MPa vs. 450 MPa ± 27 MPa) and tensile strengths (860 MPa ± 27 MPa vs. 753 MPa ± 25 MPa) and lower elongations (36% ± 5% vs. 44% ± 9%) in the as-deposited condition. Differences in mechanical properties are connected to differences in the grain size produced with the different Fe contents. In the as deposited condition, fine grains less than 500 µm in size with low aspect ratios were observed with the low Fe content, while large elongated grains in excess of 1 mm in length were observed with the high Fe content. After HIP, the yield strengths for both Fe contents decreased by 14%, while elongation increased similarly. On the other hand, tensile strengths after post processing changed by only 3%, which were correlated to higher levels of strain hardening for the higher Fe content. These differences in behavior can be attributed, in part, to changes in precipitate morphologies. After HIP post processing, the low Fe content build displayed Nb and Mo rich precipitates, while spherical Ti rich precipitates are present in the high Fe content build.

A quasi-in-situ EBSD observation of the transformation from rolling texture to recrystallization texture in V-4Cr-4Ti alloy

Recrystallization texture evolution of rolled V-4Cr-4Ti alloy has been investigated by quasi-in-situ EBSD (electron back-scattering diffraction) method. Concurrently, the precipitates were characterized by SEM (Scanning Electron Microscopy). It was found that both the initial rolling textures and the distribution of the precipitates affected the formation of the recrystallization texture. It was revealed that the texture transformations of {558} 〈110〉+{665} 〈110〉 to {334} 〈483〉+{665} 〈1 1 2.4〉 were possibly attributed to the selective drag induced by the sparsely dispersed Ti-rich precipitates. While the densely distributed Ti-rich precipitates were responsible for the randomized recrystallization texture. Finally, when the precipitates were absent, the orientation changes from {112} 〈110〉 and {558} 〈110〉 to {111} 〈112〉 and {001} 〈110〉 to {001} 〈520〉 were observed.

Ti-rich precipitate evolution in vanadium-based alloys during annealing above 400 °C

We have assessed the plate-like TiO precipitate evolution in V-4Ti and V-4Ti-4Cr alloys during isochronal annealing above 400 °C, by combining Vickers hardness, positron lifetime and coincidence Doppler broadening measurements. Our results reveal the formation of additional TiO precipitates in both alloys at temperatures of 450–600 °C in both alloys. The implanted positrons become trapped at the nm-thick TiO/matrix interface, and act as effective probes of the concomitant annealing of vacancies taking place inside the TiO precipitates above 550 °C in V-4Ti alloy. The presence of Cr in the ternary alloy not only retards the recovery of dislocations, but also enhances the oxygen diffusivity and therefore decreases the vacancy content in the TiO precipitates. These results will impact the expected alloy stability and capacity to bind light elements in the operational temperature window of these alloys for fusion reaction applications.