Longer Aging Times Research Articles

Assessing effects of ultraviolet ageing on the thermal properties and thermal degradation kinetics of long glass fiber‐reinforced polyamide 6 composites filled with zinc oxide

AbstractIn this work, the effects of ultraviolet (UV) ageing on the thermal stability, mechanical properties, and thermal degradation kinetics of long glass fiber‐reinforced polyamide 6 (PA6/LGF) composites filled with zinc oxide (ZnO) are analyzed. The composites with different contents of ZnO expose in the UV radiation of the wavelength of 340 nm for 0 to 800 h. An increase in tensile strength and a decrease in impact strength are observed with longer ageing time while samples filled with ZnO have a higher retention rate of tensile and impact strength after long time ageing. The morphology of the impact fractures of aged and unaged samples obtained by scanning electronic microscopy shows nearly no difference. Then the thermal stability and degradation kinetics of the samples with different filler fraction and different ageing time are investigated by thermal gravimetric analysis with the methods of Kissinger, Friedman, and Flynn‐Wall‐Ozawa in the dynamic measurements (10‐40°C/min). Calculated apparent activation energy (E) values by the three methods show that the samples filled with 6 wt% ZnO have a slightly lower value of E than PA6/LGF composites and nearly no change after longtime UV irradiation.

Low-velocity impact and residual flexural behaviors of 2.5-D woven composite under accelerated thermal ageing: Experiment and numerical modelling

This paper aims to investigate the thermal ageing effect on the impact and post-impact behaviors of 2.5-D woven composites. A combined experimental and numerical study is carried out over a range of impact energies with the subsequent residual flexural tests on both aged (in the air for 32 days at 180℃) and pristine samples. Low-velocity impact tests are performed to assess the degradation of impact-resistant ability in terms of energy absorption mechanism and failure modes. Subsequently, three-point bending tests are conducted to determine the post-impact behaviors with respect to strain concentration, stress transfer and damage evolution process. The strain fields in the finite element model are compared with experimental results obtained by the DIC method. A larger strain concentration area could be found at higher energy levels and longer ageing time. Extended impact damage, such as fiber breakage and delamination, plays an important role in load transfer process in post-impact behavior, thus leading to the decrease of residual stress in aged samples.

Effect of precipitation state on recrystallization texture of continuous cast AA 2037 aluminum alloy

Various states of precipitation were produced by variation of the aging treatments with and without the solution treatment and pre-deformation. The effect of the precipitation state on the recrystallization texture of continuous cast AA 2037 aluminum alloy was investigated in detail. The results show that as the precipitation state changes from the solution-treated state through the peak-aged state to the over-aged state, the strength of the cube texture decreases, whereas the strength of the R texture increases. In the peak-aged and over-aged samples, the pre-deformation prior to aging decreases the strength of the cube texture and increases the strength of the R texture, and the strength of the R component decreases significantly with increasing annealing temperature. The effect of precipitation on recrystallization in directly cold-rolled hot band is different from that in the cold-rolled solution-treated alloy. The coarser precipitates formed during long-time aging of the hot band are responsible for the stronger cube texture and coarser grains.

Intergranular corrosion behavior and mechanism of the stabilized ultra-pure 430LX ferritic stainless steel

Intergranular corrosion (IGC) behavior of the stabilized ultra-pure 430LX ferritic stainless steel (FSS) was investigated by using double loop electrochemical potentiokinetic reactivation (DL-EPR) and oxalic acid etch tests to measure the susceptibility of specimens given a two-step heat treatment. The results reveal that IGC occurs in the specimens aged at the temperature range of 600–750 °C for a short time. The aging time that is required to cause IGC decreases with the increase of aging temperature. A longer aging treatment can reduce the susceptibility to IGC. The microstructural observation shows that M23C6 precipitates form along the grain boundaries, leading to the formation of Cr-depleted zones. The presence of Cr-depleted zones results in the susceptibility to IGC. However, the atoms of stabilizing elements replace chromium atoms to form MC precipitates after long-time aging treatment, resulting in the chromium replenishment of Cr-depleted zones and the reduction of the susceptibility to IGC.

Corona ageing characteristics of composite insulators based on orthogonal experiment

To study effects of pressure, humidity and aging time on the corona aging process, aging characteristics of silicone rubber composite insulators were researched by orthogonal tests. The test platform of adjustable pressure and humidity was constructed. TSC, SEM and FTIR tests were selected for aged samples. By the range analysis, it showed that the effect of pressure on trapped charges was related to humidity and aging time. There were more trapped charges when the humidity was higher, and the influence of humidity was more obvious along with the longer aging time at a low pressure. As the pressure increased, however, the effect of humidity on trapped charges was gradually reduced. But the influence of aging time was more significant, while aged degree of silicone rubber was deepened with increasing aging time. Furthermore, the aging state of materials was the collaboration effect of charged particles and nitric acid. Moreover, it could be seen from TSC, SEM and FTIR tests, sorting results of aging states were inconsistent. Results showed that the TSC test was comprehensively embodied the corona aging characteristics caused by physical and chemical defects. Therefore, results of TSC tests could be selected as an effective criterion for aging evaluations.

Peculiarities of nanostructured state formation in heat-treatable Al–Mg alloys

The effect of long-time homogenization and aging on the formation of disperse β′ phase particles and β phase particles has been analyzed. Alloys solidified with the cooling rate of ∼10− 1 °C/s (Al–10%Mg and Al–10%Mg–0.1%Sc) and alloys melted by centrifugal casting with the cooling rate of ∼ 103 °C/s (Al–10%Mg) were chosen for comparative analysis. А significant heterogeneity of the distribution of the strengthening β′-phase after aging is observed in Al–10%Mg alloys obtained by the ingot technology. The greatest hardening up to 100% is achieved after using the centrifugal casting due to the formation of the β′-phase during aging.

Contribution of Electrical–Thermal Aging to Slot Partial Discharge Properties of HV Motor Windings

During the operation of HV motor, the abrasion of stator windings because of vibration caused by electromagnetic force will lead to slot partial discharge (PD). Furthermore, the superheat induced by overcurrent or poor heat dissipation will aggravate the slot PD. To understand the developing process of slot PD and comprehend the influences of aging factors on slot PD properties, two discharge bar models were made under electrical–thermal aging. At triple the rated line-to-earth voltage of 6 kV, two stator bars were aged for 37 days under different temperatures. The slot PD was measured during different aging stages, and visual observations of the insulation and stator core surface were made at the beginning and the end of aging. The experiment results indicate that electrical–thermal aging has a significant impact on the slot PD activities. The slot PD was intense under higher thermal stress, and the surfaces of insulation and stator core were oxidized after the long-time aging. This study can provide a judging basis for fault diagnosis of HV motors.

Tensile behaviors of thermal aged HTPB propellant at low temperatures under dynamic loading

With the purpose of further investigating the influence of aging on the tensile behaviors of hydroxyl-terminated polybutadiene (HTPB) propellant at low temperatures under dynamic loading, uniaxial tensile stress responses of thermal accelerated aged propellant samples at different temperatures (223–298 K) and strain rates ( $0.40\mbox{--}42.86~\mbox{s}^{-1}$ ) were obtained through the use of a new INSTRON testing machine. And scanning electron microscope (SEM) was employed to analyze the microscopic damage of HTPB propellant under the test conditions. Test results indicate that aging can significantly affect the characteristics of the stress-strain curves, mechanical properties and fracture mechanisms of HTPB propellant at low temperatures under dynamic loading. There are three regions in the tensile stress-strain curves of aged propellant when deforming at lower temperatures and the highest strain rate, however, there are five ones for unaged propellant. At lower temperatures and higher strain rates, the strain at maximum tensile stress of the propellant decreases more obviously after aging. Moreover, the variation of mechanical parameters for HTPB propellant with aging time are highly complex due to the occurrence of oxidative cross-linking during aging and the distinct changes of the fracture mechanisms. These variation were reasonably well described with linear model and the improved exponential model in this investigation. The fracture mechanism of aged propellant can change from dewetting, matrix tearing and AP particle fracture to only AP particle fracture with increasing strain rate for the entire test temperature range, and the strain rate for this transition is all at $4.00\mbox{--}14.29~\mbox{s}^{-1}$ . In addition, the microscopic damage of HTPB propellant becomes more severe with the thermal aging time rising, however, this effect is weaker at higher strain rates after long-time thermal aging. Finally, the master curves of typical mechanical parameters for aged HTPB propellant were constructed according to the time-temperature superposition principle (TTSP).

Mechanical and Corrosion Properties of Two Precipitation-Hardened Mg-Y-Nd-Gd-Dy Alloys with Small Changes in Chemical Composition

Precipitation hardening in Mg-Y-Nd alloys (WE-type) is based on finely dispersed particles offering an effective strengthening mechanism to achieve high strength at moderate ductility. However, these particles often affect corrosion by being more noble than the matrix. Biodegradable implant materials should show a corrosion rate fit to its application but should be free of pitting corrosion. Especially deep and narrow pits act as notches and cause increased mechanical stress leading into early failure. WE43 has already shown to have an acceptable biological response. In this study, two Mg-Y-Nd-Gd-Dy alloys, WE32 and WE33, in extruded, solution and precipitation heat-treated conditions have been investigated. The difference in alloy composition is not very high. Solution heat treatment (T4) causes grain growth and strength loss. The ageing response to peak hardness depends on the temperature. A rather short ageing response was observed for 250°C, and highest hardness has been found for 200°C at longer ageing time but higher hardness compared to 250°C. Grain growth during ageing is not significant. The higher alloyed alloy WE33 shows better mechanical strength, but less ductility. Corrosion was evaluated with immersion and potentiodynamic polarization in Ringer Acetate solution. The corrosion rate strongly depends on the alloy and heat-treatment condition as well as on the test method. The highest corrosion rate is observed in the solution-treated condition. The peak aged alloy shows the lowest corrosion rate, but non-uniform corrosion and has been evaluated by the pitting factor.

Nano-Al (OH)3 and Mg (OH)2 as flame retardants for polypropylene used on wires and cables

While materials sustainability is mostly considered in terms of their long-time aging, fires are more important—while polymers are flammable. We have developed flame retardants (FRs) for polypropylene (PP) with varied FR concentrations since PP is a very widely used polymer. Stearic acid (SA) has been added to increase filler–matrix interactions and filler dispersion in the matrix. Effects of filler types, particle size, and their concentrations on fire resistibility of different composite samples have been determined via limiting oxygen index tests and burning times. As expected, the oxygen index increases with increasing concentration of either FR. The highest value of the index is seen for 10 wt% 50 nm Al (OH)3 sample. Mixing the two hydroxides does not provide a synergy effect. The longest burning time is seen for 5 wt% 50 nm Al (OH)3 + 7 wt% SA, longer than the time for pure PP sample by 137%. Neat PP has a relatively high dynamic friction value, while addition of 5% SA results in the lowest friction value of all. The highest tensile modulus is seen for PP with 7.5 wt% 15 nm Al (OH)3 particle addition. Thermogravimetric analysis shows high thermal stability for PP with 5% each of Al (OH)3 and Mg (OH)2. Scanning electron microscopy shows that the surfaces of Al (OH)3-containing samples are slightly rougher than those with Mg (OH)2. Energy dispersive X-ray spectroscopy shows uniform distribution of both Al and Mg atoms in the composites.

The influence of photochemical aging on light absorption of atmospheric black carbon and aerosol single-scattering albedo

Abstract. Coating enhancement of black carbon (BC) light absorption (Eabs) is a large uncertainty in modelling direct radiative forcing (DRF) by BC. Reported Eabs values after atmospheric aging vary widely and the mechanisms responsible for enhancing BC absorption remain elusive. Here, we report on the direct field measurement of size-resolved mixing state, Eabs, and aerosol single-scattering albedo (SSA) at λ = 532 nm at a rural site in east China from June to July 2016. Strong diurnal variability of Eabs, SSA, and Ox (Ox = NO2 + O3, a proxy for atmospheric photochemical aging) was observed. A method that combined Eabs and SSA was developed to retrieve the fraction contribution of BC absorption (fBC), lensing-driven enhancement (fLens), as well as the fractional contribution of coating absorption (fraction absorption contribution (fShell), the coated shell diameter (DShell) and the imaginary part of the complex refractive index (CRI) of the shell (kShell)). Parameterization of Eabs and SSA captures much of the influence of BC coating and the particle absorption. In our measurements at this site, the results showed that the absorption amplification depended on the coating thickness and the absorption of coating materials, and photochemistry plays a role in modifying the absorption of BC-containing particles. The lensing-driven enhancement was reduced by light absorption of the shell. One implication of these findings is that the contribution of light-absorbing organic compounds (brown carbon, BrC) at a longer aging time should be included in climate models.

Identification of Maize Kernel Vigor under Different Accelerated Aging Times Using Hyperspectral Imaging.

Seed aging during storage is irreversible, and a rapid, accurate detection method for seed vigor detection during seed aging is of great importance for seed companies and farmers. In this study, an artificial accelerated aging treatment was used to simulate the maize kernel aging process, and hyperspectral imaging at the spectral range of 874–1734 nm was applied as a rapid and accurate technique to identify seed vigor under different accelerated aging time regimes. Hyperspectral images of two varieties of maize processed with eight different aging duration times (0, 12, 24, 36, 48, 72, 96 and 120 h) were acquired. Principal component analysis (PCA) was used to conduct a qualitative analysis on maize kernels under different accelerated aging time conditions. Second-order derivatization was applied to select characteristic wavelengths. Classification models (support vector machine−SVM) based on full spectra and optimal wavelengths were built. The results showed that misclassification in unprocessed maize kernels was rare, while some misclassification occurred in maize kernels after the short aging times of 12 and 24 h. On the whole, classification accuracies of maize kernels after relatively short aging times (0, 12 and 24 h) were higher, ranging from 61% to 100%. Maize kernels with longer aging time (36, 48, 72, 96, 120 h) had lower classification accuracies. According to the results of confusion matrixes of SVM models, the eight categories of each maize variety could be divided into three groups: Group 1 (0 h), Group 2 (12 and 24 h) and Group 3 (36, 48, 72, 96, 120 h). Maize kernels from different categories within one group were more likely to be misclassified with each other, and maize kernels within different groups had fewer misclassified samples. Germination test was conducted to verify the classification models, the results showed that the significant differences of maize kernel vigor revealed by standard germination tests generally matched with the classification accuracies of the SVM models. Hyperspectral imaging analysis for two varieties of maize kernels showed similar results, indicating the possibility of using hyperspectral imaging technique combined with chemometric methods to evaluate seed vigor and seed aging degree.

Influence of thermo‐oxidative aging on the dynamical mechanical properties and thermal degradation kinetics of glass fiber‐reinforced PA10T composites

Unveiling the fundamental thermal‐oxidative aging mechanism and thermal degradation kinetics of the poly(decamethyleneterephthalamide) (PA10T)/ glass fiber (GF) composites under different aging temperatures (160°C, 200°C, and 240°C) for 0–50 days will facilitate the understanding of the interaction between matrix PA10T and GF. The results revealed that the decrease of mechanical properties referring to tensile strength, flexural strength and notched impact strength, and the occurrence of debonding phenomenon between PA10T matrix and GF were increasingly obvious after longer aging time at higher aging temperature. At the same time, the decline of crystalline was mainly ascribed to the thermal‐oxidative aging effect, which triggered the deterioration of mechanical properties of PA10T/GF composites. Accordingly, the enhancement of rigidity were probably attributed to the higher temperature aging effect with the aging time prolonging in PA10T/GF composites, while the interfacial debonding between GF and resin matrix obviously occurred with the increase of aging time. In a word, it is believed that investigating the fundamental thermal‐oxidative aging of PA10T/GF composites would be beneficial to optimize and control the service life and applications of materials. POLYM. ENG. SCI., 59:643–656, 2019. © 2018 Society of Plastics Engineers

Influence of solidification induced composition gradients on carbide precipitation in FeNiCr heat resistant steels

Secondary precipitation of Cr-rich carbides in heat resistant austenitic stainless steels has been investigated both experimentally and using finite element simulations. The microstructural evolutions in two commercial grades were characterized using electron microscopy. A special emphasis was given on the peculiar spatial distribution of M23C6 secondary carbides exhibiting precipitate free zones surrounding primary carbides, and high density precipitate zones extending with longer aging times. Solidification induced chemical composition gradients were clearly exhibited in the as-cast alloys with significant chromium depletion in the vicinity of primary M7C3 carbides. It is then proposed that these gradients play a major role in the secondary precipitation mechanism. Classical nucleation and growth theories have been adapted to account for (i) the flux of solutes with large difference in diffusion coefficients, (ii) the initial composition gradients in the matrix and, (iii) the chemical driving force for nucleation and growth of M23C6 carbides. Within this framework, the whole kinetics has been reproduced. It clearly shows that the spatial distribution of secondary carbides that play a key role in the creep resistance of these alloys is the result of a complex interaction between initial composition gradients in as-cast alloys and solute flux resulting from phase transformation during aging.

Evaluation of Residual Stress Relaxation in a Rolled Joint by Neutron Diffraction

The rolled joint of a pressure tube, consisting of three axial symmetric parts, modified SUS403 stainless steel as an inner extension, Zr–2.5Nb as the pressure tube and an Inconel-718 outer sleeve has been examined by neutron diffraction for residual stresses. It was heat treated to 350 °C for 30, 130 and 635 h to simulate thermal aging over the lifetime of an advanced thermal reactor respectively for 1, 5 and 30 years at an operating temperature of 288 °C. The crystallographic texture has been investigated from cylindric disks cut from the heat treated Zr–2.5Nb pressure tube to determine the proper sample-orientation-dependent hkl reflections for reliable residual strain measurements. Corresponding in situ tensile deformation was carried out to obtain the necessary diffraction elastic constants for the residual stress evaluation. Three-dimensional crystal lattice strains at various locations in the rolled joint before and after the aging treatments for various times were non-destructively measured by neutron diffraction and the residual stress distribution in the rolled joint was evaluated by using the Kröner elastic model and the generalized Hooke’s law. In the crimp region of the rolled joint, it was found that the aging treatment had a much weaker effect on the residual stresses in the Inconel outer sleeve and the modified SUS403 stainless steel extension. In the non-aged Zr–2.5Nb pressure tube, the highest residual stresses were found near its interface with the modified SUS430 stainless steel extension. In the crimp region of the Zr–2.5Nb pressure tube near its interface with the modified SUS430 stainless steel, the average compressive axial stress was −440 MPa, having no evident change during the long-time aging. In the Zr–2.5Nb pressure tube outside closest to the crimp region, the tensile axial and hoop stresses were relieved during the 30 h of aging. The hoop stresses in the crimp region evolved from an average tensile stress of 80 MPa to an average compressive stress of 230 MPa after the 635 h of aging, suggesting that the rolled joint had a good long-term sealing ability against leakage of high temperature water. In the Zr–2.5Nb pressure tube close to the reactor core and far away from the modified SUS403 stainless steel extension, the residual stresses near the inside surface of the pressure tube were almost zero, helping to keep a good neutron irradiation resistance.

Impact of the aging of a photovoltaic module on the performance of a grid-connected system

Photovoltaic systems belong to the green energy dynamics which is an ambitious program based on energy efficiency and sustainable development. In this study, the impact of the aging of a photovoltaic module is investigated on the electrical performance of a grid-connected system. A photovoltaic conversion chain with MPPT (Maximum Power Point Tracking) control and LC (Inductor-Capacitor) filter is modeled and dimensioned according to the grid constraints. A method of hybridation detection of the MPPT coupling long-time aging evolution and short-time determination is proposed. Aging laws for the electrical and optical degradations of the photovoltaic module are introduced for the long-time evolution. Results display the lowering of the maximal power point with a rate of 1%/year and a slight augmentation of the THD over time even though it remains inferior to the IEEE standard STD 19-1992 maximum value of 5% for a usage of 20 years. Moreover, an equivalent scheme for the additional electrical resistance engendered by the aging of the photovoltaic module regarding other resistances of the photovoltaic system is given. Finally, the elevation of this resistance by 12.8% in 20 years may have non-negligible consequences on the power production of a large-scale installation.

Temporal evolution of a model Co-Al-W superalloy aged at 650 °C and 750 °C

The temporal evolution of a γ(f.c.c.)/γ’ (L12) Co-8.8Al-7.3 W superalloy aged at 650 °C (10 min–4096 h) and 750 °C (10 min–256 h) is studied utilizing atom-probe tomography (APT), scanning electron microscopy, and Vickers microhardness testing. The evolution of the phase compositions, γ’ (L12) volume fraction, and mean precipitate radius, <R2-D(t)>, are determined. Coarsening rate constants and temporal exponents are calculated for <R-D(t)> of the γ’ (L12)-nanoprecipitates. The temporal exponents are found to be generally close to 1/p = 1/3 as required for diffusion-limited coarsening. Tungsten solid-solubility is significantly reduced in the γ(f.c.c.)-matrix at 650 °C (0.54 ± 0.04 at. %) and 750 °C (1.35 ± 0.06 at. %) when compared with aging at 900 °C (5.5 at. %). The value of <R2D(t)> of the γ’ (L12)-nanoprecipitates increases with increasing aging time corresponding to an increase in the Vickers microhardness; the peak strength was not, however, achieved for the aging times investigated. The morphology of the γ’ (L12)-nanoprecipitates begins as spheroids but transitions to cuboids at longer aging times, with final the γ’ (L12) volume fractions for aging at 650 °C and 750 °C being ϕ = 53% and 54%, respectively. The effect of quench-rate (either furnace-cooled, air-cooled, oil quenched, or water quenched) from a supersolvus temperature of 1050 °C on the microstructure of the alloy is also investigated. Slow cooling (furnace and air-cooling) is shown to result in a uniform distribution of nanometer sized γ’ (L12)-nanoprecipitates, unlike Ni-based superalloys in which the γ’ (L12)-nanoprecipitates form in a non-uniform or multimodal distribution.

The influence of aging temperature and aging time on the mechanical and tribological properties of selective laser melted maraging 18Ni-300 steel

Selective laser melting (SLM) is an additive manufacturing and 3D printing technology which offers flexibility in geometric design and rapid production of complex structures. Maraging steels have high strength and good ductility, and therefore have been widely used in aerospace and tooling sectors for many years. This work aims to study the influence of aging temperature and aging time on the microstructure, mechanical property (hardness, strength and ductility) and tribological property of SLM maraging 18Ni-300 steel. The results reveal that the aging conditions had a significant impact on the strength and wear-resistance of the SLM maraging steel. The optimal aging conditions for the SLM maraging steel produced in this work were 490 °C for 3 h under which strength and wear-resistance were maximised. Lower or higher aging temperature led to under-aging or over-aging phenomena, reducing the strength and wear-resistance performance. Shorter or longer aging time also resulted in the decrease of strength and wear-resistance performance of the SLM maraging steel as compared with the optimal conditions. The variation of the mechanical and tribological properties is primarily due to changes in phase compositions and microstructures of the SLM maraging steels.

Aging Effects on the Structural and Magnetic Properties of Terbium–Aluminium Co-doping of Yttrium Iron Garnet Films Prepared Using the Sol–Gel Method

The terbium–aluminium co-doped yttrium iron garnet (Tb0.2Y2.8Al1Fe4O12) nanoparticles films, prepared via a sol–gel method, were aged variously for 2 days, 3 days, 4 days and 5 days. The films were deposited on quartz substrates using a spin coating technique then annealed at 900°C in air for 2 h. The microstructural and magnetic properties of the films were measured using an x-ray diffractometer (XRD), a field emission scanning electron microscope and a vibrating sample magnetometer. The XRD results showed that all the resultant films were a single phase regardless of aging time. A change in the lattice parameter’s behavior was observed at the longer aging times. At an aging time of 5 days, the films became highly agglomerated and exhibited the greatest thickness value of 458.9 nm. The saturation magnetization, Ms, of the films decreased from 31 kA/m to 6 kA/m as the aging time was increased from 2 days to 5 days, due to the increasing Fe–O bond length resulting from larger grain sizes. The increase in aging time to 5 days caused a reduction in the coercivity, Hc, of films due to the multi-domain formation.

Characterizing nanoscale precipitation in a titanium alloy by laser-assisted atom probe tomography

Atom-probe tomography was performed on the metastable β-Ti alloy, Ti-5Al-5Mo-5V-3Cr wt% (Ti-5553), aged at 300 °C for 0 to 8 h, to precipitate the embrittling isothermal ω phase. Accurate precipitate quantification requires monitoring and controlling suitable charge-state ratios in the mass spectrum, which in turn are closely related to the laser pulse energy used. High ultraviolet laser pulse energies result in significant complex molecular ion formation during field-evaporation, causing mass spectral peak overlaps that inherently complicate data analyses. Observations and accurate quantification of the ω-phase under such conditions are difficult. The effect is minimized or eliminated by using smaller laser pulse energies. With a small laser pulse energy, Ti-rich and solute depleted precipitates of the isothermal ω phase with an oxygen enriched interface are observed as early as after 1 h aging time utilizing the LEAP 5000X S (77% detection efficiency). We note that these precipitates were not detected below a 2 h aging time with the LEAP 4000X Si (58% detection efficiency). The results are compared to the archival literature. The Al concentration in the matrix/precipitate interfacial region increases during aging. Nucleation of the α-phase at longer aging times may be facilitated by the O and Al enrichment at the matrix/precipitate interface (both strong α-stabilisers). The kinetics and compositional trajectory of the ω-phase with aging time are quantified, facilitating direct correlation of the APT data to previously published mechanical testing.