Traditionally, FeCrAl alloys played an important role in high-temperature applications due to their ability to form a passive Al oxide film at temperatures above ~ 800 °C. Recently, FeCrAl alloys became of interest for the application of accident tolerant nuclear fuel cladding. This study covers work done at GE Research for better understanding the role of Al, Cr, and Mo in oxidation kinetics and thermodynamics. Several models and commercial prototype alloys have been tested in hydrothermal corrosion autoclave loops, at low temperature steam exposure (~ 400 °C), high temperature steam exposure (~ 1000 °C or higher), and high temperature air exposures. The results provide insights on how chromium and aluminum play a significant role in both high temperature and low temperature oxidation of FeCrAl. Additionally, machine learning tools are used to gain further insights on both predicting future optimized chemistries for balancing the properties of hydrothermal corrosion, low and high temperature steam oxidation, and thermal aging (which is exacerbated due to radiation in a nuclear reactor environment). GE plans to use this framework to further optimize the FeCrAl alloy system for use in nuclear reactor environments. Graphical abstract

FeCrAl alloys are among the most promising candidates for accident-tolerant fuel cladding material in light water nuclear reactors. Despite their high-temperature oxidation resistance in corrosive environments coupled with their hydrothermal corrosion resistance, a key challenge remains in optimizing the composition of the alloy that can be achieved through statistical analysis. However, the current literature on FeCrAl alloy design lack studies for designing alloys based on oxidation resistance. This study addresses that gap by developing a predictive model for the oxidation of FeCrAl alloys based on an experimental dataset, which lays the groundwork for model-based optimization for alloy composition.

Abstract Traditionally, FeCrAl alloys played an important role in high-temperature applications due to their ability to form a passive Al oxide film at temperatures above ~800°C. Recently, FeCrAl alloys became of interest for the application of accident tolerant nuclear fuel cladding. This study covers work done at GE Research for better understanding the role of Al, Cr, and Mo in oxidation kinetics and thermodynamics. Several models and commercial prototype alloys have been tested in hydrothermal corrosion autoclave loops, at low temperature steam exposure (~400°C), high temperature steam exposure (~1000°C or higher), and high temperature air exposures. The results provide insights on how chromium and aluminum play a significant role in both high temperature and low temperature oxidation of FeCrAl. Additionally, machine learning tools are used to gain further insights on both predicting future optimized chemistries for balancing the properties of hydrothermal corrosion, low and high temperature steam oxidation, and thermal aging (which is exacerbated due to radiation in a nuclear reactor environment). GE plans to use this framework to further optimize the FeCrAl alloy system for use in nuclear reactor environments.

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Inspection of materials for defects and anomalies in high-throughput industrial settings require the collection of dependable, high quality data acquired at a rapid pace. Human errors related to sample tracking and data management along with unintentional deviations from established protocols must be minimized. We have developed a custom system designed to accelerate acquisition of routine electron microprobe analyses by implementing computer vision to track and analyze features of interest. This system’s built-in modularity provides a solution that is applicable to various material systems, thereby maintaining flexibility in an industrial research setting where projects and samples are everchanging. Inspections performed using an electron microprobe typically involve one to three mounts in the machine at one time (depending on the size of the sample), each with multiple locations of interest. Numerous features are then analyzed within each location. For a typical mount containing 10 locations of interest, we estimate an average total analysis time (from preparation of the mount to reporting) to be ~400 minutes. Of that total, ~25% of the time spent is devoted to point selection by the operator (Figure 1); a task that could easily be automated. Our system is built on a JEOL 8530F electron probe microanalyzer running Probe for EPMA (PFE) software with an attached Thermo Scientific Noran System 7 scan generator. A customized user interface communicates with the system through two APIs (application programming interfaces): Probe Software’s Remote Automation Interface [1] and Thermo Scientific’s Microanalysis Portal [2]. Two APIs were necessary to overcome two main challenges: (1) slow image acquisition (minimum pixel dwell ~200 msec) using the JEOL 8520/8530 interface with PFE Remote (version 12.6.2);

Purpose The combined hyperpolarized (HP) 13 C pyruvate and urea MRI has provided a simultaneous assessment of glycolytic metabolism and tissue perfusion for improved cancer diagnosis and therapeutic evaluation in preclinical studies. This work aims to translate this dual‐probe HP imaging technique to clinical research. Methods A co‐polarization system was developed where [1‐ 13 C]pyruvic acid (PA) and [ 13 C, 15 N 2 ]urea in water solution were homogeneously mixed and polarized on a 5T SPINlab system. Physical and chemical characterizations and toxicology studies of the combined probe were performed. Simultaneous metabolic and perfusion imaging was performed on a 3T clinical MR scanner by alternatively applying a multi‐slice 2D spiral sequence for [1‐ 13 C]pyruvate and its downstream metabolites and a 3D balanced steady‐state free precession (bSSFP) sequence for [ 13 C, 15 N 2 ]urea. Results The combined PA/urea probe has a glass‐formation ability similar to neat PA and can generate nearly 40% liquid‐state 13 C polarization for both pyruvate and urea in 3‐4 h. A standard operating procedure for routine on‐site production was developed and validated to produce 40 mL injection product of approximately 150 mM pyruvate and 35 mM urea. The toxicology study demonstrated the safety profile of the combined probe. Dynamic metabolite‐specific imaging of [1‐ 13 C]pyruvate, [1‐ 13 C]lactate, [1‐ 13 C]alanine, and [ 13 C, 15 N 2 ]urea was achieved with adequate spatial (2.6 mm × 2.6 mm) and temporal resolution (4.2 s), and urea images showed reduced off‐resonance artifacts due to the J CN coupling. Conclusion The reported technical development and translational studies will lead to the first‐in‐human dual‐agent HP MRI study and mark the clinical translation of the first HP 13 C MRI probe after pyruvate.

At GE Research, we are combining “physics” with artificial intelligence and machine learning to advance manufacturing design, processing, and inspection, turning innovative technologies into real products and solutions across our industrial portfolio. This article provides a snapshot of how this physical plus digital transformation is evolving at GE.

Differential thermal analysis (DTA) has been conducted on directionally solidified near-eutectic Sn-3.0 wt.%Ag-0.5 wt.%Cu (SAC), SAC \(+\) 0.2 wt.%Sb, SAC \(+\) 0.2 wt.%Mn, and SAC \(+\) 0.2 wt.%Zn. Laser ablation inductively coupled plasma mass spectroscopy was used to study element partitioning behavior and estimate DTA sample compositions. Mn and Zn additives reduced the undercooling of SAC from 20.4\(^\circ \hbox {C}\) to \(4.9^\circ \hbox {C}\) and \(2^\circ \hbox {C}\), respectively. Measurements were performed at cooling rate of \(10^\circ \hbox {C}\) per minute. After introducing 200 ppm \(\hbox {O}_2\) into the DTA, this undercooling reduction ceased for SAC \(+\) Mn but persisted for SAC \(+\) Zn.

Computer-controlled scanning electron microscopy (CC-SEM) is an automated technique combining electron microscopy, image analysis, and X-ray spectroscopy to rapidly acquire morphological and chemical information for thousands of individual particles. Measurements are typically performed on polished cross-sections of material embedded in epoxy mounts. Individual particles are first identified from the epoxy matrix based on user-specified criteria (e.g., pre-set grayscale threshold from a representative Back-Scattered Electron image). Following identification, morphologic parameters (e.g., area, perimeter, aspect ratio, etc.) and an X-ray spectrum (EDS) are recorded for each particle. Multiple fields of view can be analyzed, resulting in many thousands of individual particle analyses collected during a single CC-SEM session. The resulting data can then be mined for useful information like particle size distributions (PSDs), phase proportions, and even bulk chemistry.

We have calculated slab fluid temperatures for 51 volcanoes in 10 subduction zones using the newly developed H2O/Ce thermometer. The slab fluid compositions were calculated from arc eruptives, using melt inclusion‐based H2O contents, and were corrected for background mantle contributions. The temperatures, adjusted to h, the vertical depth to the slab beneath the volcanic arc, range from ∼730 to 900°C and agree well (within 30°C on average for each arc) with sub‐arc slab surface temperatures predicted by recent thermal models. The coherence between slab model and surface observation implies predominantly vertical transport of fluids within the mantle wedge. Slab surface temperatures are well reconciled with the thermal parameter (the product of slab age and vertical descent rate) andh. Arcs with shallow h (∼80 to 100 km) yield a larger range in slab surface temperature (up to ∼200°C between volcanoes) and more variable magma compositions than arcs with greater h (∼120 to 180 km). This diversity is consistent with coupling of the subducting slab and mantle wedge, and subsequent rapid slab heating, at ∼80 km. Slab surface temperatures at or warmer than the H2O‐saturated solidus suggest that melting at the slab surface is common beneath volcanic arcs. Our results imply that hydrous melts or solute‐rich supercritical fluids, and not H2O‐rich aqueous fluids, are thus the agents of mass transport to the mantle wedge.

We compiled a data set of 100 primitive arc magma compositions from melt inclusion and whole rock analyses to compare volatile contents, slab tracers, and calculated subduction component compositions between 18 subduction zone segments spanning the global range in slab thermal structure. The average primitive magma H 2 O content in our data set is 3.3 ± 1.2 wt.% (1 s.d.) for melts erupted within 50 km of the volcanic front. While there is a wide range of volatile contents in magmas within individual arcs, the highest values occur in magmas erupted from vents along the volcanic front, where the subducting slab is located 104 ± 29 km (avg ± 1 s.d.) beneath the surface. This observation, coupled with positive correlations between H 2 O, Cl, S, and B contents and predictions from geodynamic models, provides strong evidence for the active supply of volatile‐rich slab‐derived components from the subducting oceanic plate beneath volcanic arcs. We also show that temperature‐sensitive ratios (e.g., H 2 O/Ce) for both primitive arc magmas and calculated subduction components are similar and display monotonic behavior with slab thermal parameter. Furthermore, calculated subduction component compositions have higher trace element to H 2 O ratios in arcs with hotter slabs (lower thermal parameter), suggesting that hydrous melts of differing compositions are added beneath different arcs. Finally, we present new volatile outflux estimates for Central Cascades magmatism and then compare these to estimates for the Central American and Kamchatka‐Kurile arcs to create a combined data set spanning a large range in slab thermal parameter.

Primitive chemical characteristics of high-Mg andesites (HMA) suggest equilibration with mantle wedge peridotite, and they may form through either shallow, wet partial melting of the mantle or re-equilibration of slab melts migrating through the wedge. We have re-examined a well-studied example of HMA from near Mt. Shasta, CA, because petrographic evidence for magma mixing has stimulated a recent debate over whether HMA magmas have a mantle origin. We examined naturally quenched, glassy, olivine-hosted (Fo87–94) melt inclusions from this locality and analyzed the samples by FTIR, LA-ICPMS, and electron probe. Compositions (uncorrected for post-entrapment modification) are highly variable and can be divided into high-CaO (>10 wt%) melts only found in Fo > 91 olivines and low-CaO (<10 wt%) melts in Fo 87–94 olivine hosts. There is evidence for extensive post-entrapment modification in many inclusions. High-CaO inclusions experienced 1.4–3.5 wt% FeOT loss through diffusive re-equilibration with the host olivine and 13–28 wt% post-entrapment olivine crystallization. Low-CaO inclusions experienced 1–16 wt% olivine crystallization with <2 wt% FeOT loss experienced by inclusions in Fo > 90 olivines. Restored low-CaO melt inclusions are HMAs (57–61 wt% SiO2; 4.9–10.9 wt% MgO), whereas high-CaO inclusions are primitive basaltic andesites (PBA) (51–56 wt% SiO2; 9.8–15.1 wt% MgO). HMA and PBA inclusions have distinct trace element characteristics. Importantly, both types of inclusions are volatile-rich, with maximum values in HMA and PBA melt inclusions of 3.5 and 5.6 wt% H2O, 830 and 2,900 ppm S, 1,590 and 2,580 ppm Cl, and 500 and 820 ppm CO2, respectively. PBA melts are comparable to experimental hydrous melts in equilibrium with harzburgite. Two-component mixing between PBA and dacitic magma (59:41) is able to produce a primitive HMA composition, but the predicted mixture shows some small but significant major and trace element discrepancies from published whole-rock analyses from the Shasta locality. An alternative model that involves incorporation of xenocrysts (high-Mg olivine from PBA and pyroxenes from dacite) into a primary (mantle-derived) HMA magma can explain the phenocryst and melt inclusion compositions but is difficult to evaluate quantitatively because of the complex crystal populations. Our results suggest that a spectrum of mantle-derived melts, including both PBA and HMA, may be produced beneath the Shasta region. Compositional similarities between Shasta parental melts and boninites imply similar magma generation processes related to the presence of refractory harzburgite in the shallow mantle.

The Cascades arc is a warm-slab subduction zone characterized by the slow (3.5cm/a) subduction of young (<10Ma) oceanic crust. Elevated slab temperatures likely result in shallow dehydration beneath the forearc and reduced slab fluid addition to the mantle wedge beneath the volcanic front. Resulting calc-alkaline magmas should contain low volatile abundances relative to arcs with cooler subducting slabs. We test this hypothesis in Central Oregon, the region of the arc that has experienced the highest mafic output over the last 2Ma. Naturally quenched basalt and basaltic andesite melt inclusions from tephra erupted from monogenetic vents record pre-eruptive magmatic volatile contents. After accounting for the effects of degassing, our data show that initial volatile contents from seven calc-alkaline cinder cones range from 1.7 to 3.6wt.% H2O, 1200–2100ppm S and 500–1200ppm Cl. Ratios reflecting volatiles recycled from the subducted slab (H2O/Ce ~490–1700; S/Nb ~110–310; and Cl/Nb ~37–190) are elevated above MORB values but are low compared to those from the southern Cascades (Mount Shasta) and other arcs (Mexico, Central America, and Kamchatka). Positive correlations between H2O, Pb/Ce and Ba/Zr suggest that small additions of a slab-derived component to the mantle wedge are responsible for observed volatile contents.