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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Evolution of the substructure of a novel 12% Cr steel under creep conditions

In this work we study the microstruture evolution of a newly developed 12% Cr martensitic/ferritic steel in as-received condition and after creep at 650 °C under 130 MPa and 80 MPa. The microstructure is described as consisting of mobile dislocations, dipole dislocations, boundary dislocations, precipitates, lath boundaries, block boundaries, packet boundaries and prior austenitic grain boundaries. The material is characterized employing light optical microscopy (LOM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). TEM is used to characterize the dislocations (mobile + dipole) inside the subgrains and XRD measurements are used to the characterize mobile dislocations. Based on the subgrain boundary misorientations obtained from EBSD measurements, the boundary dislocation density is estimated. The total dislocation density is estimated for the as-received and crept conditions adding the mobile, boundary and dipole dislocation densities. Additionally, the subgrain size is estimated from the EBSD measurements. In this publication we propose the use of three characterization techniques TEM, XRD and EBSD as necessary to characterize all type of dislocations and quantify the total dislocation densty in martensitic/ferritic steels. - Highlights: • Creep properties of a novel 12% Cr steel alloyed with Ta • Experimental characterization of different types of dislocations: mobile, dipole and boundary • Characterization and interpretation of the substructure evolution using unique combination of TEM, XRD and EBSD.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Effect of cold rolling on the microstructural evolution of new β-typed Ti–6Mo–6V–5Cr–3Sn–2.5Zr alloys

A Ti–6Mo–6V–5Cr–3Sn–2.5Zr (wt.%) alloy was designed as a new metastable β-Ti alloy. The effect that cold rolling had on the microstructural evolution of the material was investigated via optical microscopy (OM), X-ray diffraction (XRD), electron back-scattered diffraction (EBSD) and transmission electron microscopy (TEM) measurements. A single β phase formed in the alloy after solution treatment at 780 °C for 30 min followed by water quenching. The solution-treated alloy was cold rolled with thickness reductions of 10%, 30%, 50% and 70%, and the hardness values increased as the thickness of the specimen decreased. The textures of the cold rolled specimen were characterized according to the 〈110〉 partial parallel to the rolling direction as the rolling reduction increased. The crystallographic orientation showed principal α-fiber textures for (111)〈110〉 and (112)〈110〉. The cold deformation led to the appearance of martensite α″ phases, particularly stress-induced martensite (SIM) α″ phases. - Highlights: • Effect of cold rolling on new β-typed Ti-6Mo-6V-5Cr-3Sn-2.5Zr alloy was studied. • A single β phase was obtained after solution treatment at 780 °C for 30 min. • α-Fiber textures became dominated with the increase in cold rolling reduction. • A stress-induced α″ martensite was caused by cold rolling.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Microstructure development and texture evolution of aluminum multi-port extrusion tube during the porthole die extrusion

Aluminum multi-port extrusion tube is processed by the porthole die extrusion and the internal tube walls are welded through the solid state metallurgical bonding. In order to observe the development of grains and their orientations under severe plastic deformation and solid state welding, the extrusion butt together with the die is quenched immediately after extrusion to preserve the grain structure in the processing. The forming histories of selected material points are obtained by analyzing the optical microscopy graph. The evolution of the microstructure along the forming path is characterized by electro backscattered diffraction. It is found that geometrical dynamic recrystallization happens in the process. Grains are elongated, scattered at the transition zone and shear intensive zone, and then pinched off when they are pushed out from the die orifice. The shear-type orientations are predominant at the surface layer on the longitudinal section of the tube web and have penetrated into the intermediate layer. The rolling-type orientations are formed at the central layer. Texture gradient through the thickness of the tube web is observed. And cube orientated grains are found at the seam weld region. - Highlights: •Microstructure of extrusion butt is preserved after the micro scale porthole die extrusion. •Grain morphology history along forming path is investigated. •Texture evolutions on three material flows are present. •Texture gradient exists on the longitudinal section of the internal wall of profile. •Rolling-type and cube textures are found at the solid state welding region.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Evaluation of Aluminum-Boron Carbide Neutron Absorbing Materials for Interim Storage of Used Nuclear Fuel

The objective of this work was to understand the corrosion behavior of Boral® and Bortec® neutron absorbers over long-term deployment in a used nuclear fuel dry cask storage environment. Corrosion effects were accelerated by flowing humidified argon through an autoclave at temperatures up to 570°C. Test results show little corrosion of the aluminum matrix but that boron is leaching out of the samples. Initial tests performed at 400 and 570°C were hampered by reduced flow caused by the rapid build-up of solid deposits in the outlet lines. Analysis of the deposits by XRD shows that the deposits are comprised of boron trioxide and sassolite (H 3 BO 3 ). The collection of boron- containing compounds in the outlet lines indicated that boron was being released from the samples. Observation of the exposed samples using SEM and optical microscopy show the growth of new phases in the samples. These phases were most prominent in Bortec® samples exposed at 570°C. Samples of Boral® exposed at 570°C showed minimal new phase formation but showed nearly the complete loss of boron carbide particles. Boron carbide loss was also significant in Boral samples at 400°C. However, at 400°C phases similar to those found in Bortec® were observed. The rapid loss of the boron carbide particles in the Boral® is suspected to inhibit the formation of the new secondary phases. However, Material samples in an actual dry cask environment would be exposed to temperatures closer to 300°C and less water than the lowest test. The results from this study conclude that at the temperature and humidity levels present in a dry cask environment, corrosion and boron leaching will have no effect on the performance of Boral® and Bortec® to maintain criticality control.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

New compositional data on ancient mortars and plasters from Pompeii (Campania – Southern Italy): Archaeometric results and considerations about their time evolution

Highlights: • Mortar samples from Pompeii, with different constructive functions, were studied. • Characterization of the materials can be used for preparing compatible mortars. • Analogies and differences were highlighted to identify the constructive phases. • Preliminary statistic models were proposed to discriminate materials and constructive phases. Twenty-six samples of mortar used for various construction applications (joint mortars, floor mortars, filling mortars and plasters) were collected from different areas of the archaeological site of Pompeii (Campania - Sothern Italy). The mortar samples belong to various historical periods covering approximately 2000 years, from the 2nd century BC to the post excavation period (18–19th century). The samples were characterized employing Optical Microscopy (OM), X-ray Powder Diffraction (XRPD), X-ray Fluorescence (XRF), Electron Probe Micro Analysis (EPMA) and Raman Spectroscopy. Moreover, image analysis was carried out using JMicroVision software in order to determine the percentages of binder, macropores and aggregate, in terms of crushed ceramic fragments (cocciopesto), rock fragments and monocrystals. The application of these techniques allowed obtaining a complete chemical and minero-petrographic characterization of the samples, which may prove useful for preparing compatible repair mortars for future restoration works. The archaeometric study provided new data on the production technology of the mortars and the analogies and differences observed among the samples, enabled us to distinguish different constructive phases, thus confirming or rebutting the archaeological hypothesis on the dating of some samples. By combining compositional variables through the discriminant analysis, it was also possible to analyse the time evolution of the materials and to construct preliminary multivariate statistical models, helpful to identify the various typologies of mortars used in the different historical periods.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Fabrication of Pt nanowires with a diffraction-unlimited feature size by high-threshold lithography

Although the nanoscale world can already be observed at a diffraction-unlimited resolution using far-field optical microscopy, to make the step from microscopy to lithography still requires a suitable photoresist material system. In this letter, we consider the threshold to be a region with a width characterized by the extreme feature size obtained using a Gaussian beam spot. By narrowing such a region through improvement of the threshold sensitization to intensity in a high-threshold material system, the minimal feature size becomes smaller. By using platinum as the negative photoresist, we demonstrate that high-threshold lithography can be used to fabricate nanowire arrays with a scalable resolution along the axial direction of the linewidth from the micro- to the nanoscale using a nanosecond-pulsed laser source with a wavelength λ{sub 0} = 1064 nm. The minimal feature size is only several nanometers (sub λ{sub 0}/100). Compared with conventional polymer resist lithography, the advantages of high-threshold lithography are sharper pinpoints of laser intensity triggering the threshold response and also higher robustness allowing for large area exposure by a less-expensive nanosecond-pulsed laser.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

SNOM Imaging of a Crypt-Like Feature in Adenocarcinoma Associated with Barrett's Oesophagus

The development of more accurate and sensitive diagnostic techniques is a key factor in efforts to improve cancer survival rates. The technique of infrared aperture fibre scanning near-field optical microscopy (IR-SNOM),together with radiation from the infrared free-electron laser (IR-FEL) on ALICEat Daresbury Laboratory (UK), has been used to obtain IR images of a crypt-like feature and the surrounding tissue; the tissue was taken from a patient with oesophageal adenocarcinoma and with a history of Barrett’s oesophagus. We have shown that the DNA signal is enhanced relative to other contributions in the region of the crypt, and the glycoprotein signal shows a less pronounced increase in the region of the crypt. The Amide II signal is found to be anti-correlated with the DNA and glycoprotein profiles. The absorbance of the Amide II signal is found to differ for three different types of cancer tissue. In conclusion, high-resolution IR images of the crypt reveal additional structure that would not be resolved in diffraction-limited techniques.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Phase structures and morphologies of tempered CA6NM stainless steel welded by hybrid laser-arc process

The post-weld tempered microstructure of hybrid laser-arc welded CA6NM, a cast low carbon martensitic stainless steel, was investigated. The microstructural evolutions from the fusion zone to the base metal were characterized in detail using optical microscopy, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), X-ray diffraction (XRD) and microhardness techniques. The fusion zone, in its post-weld tempered condition, consisted of tempered lath martensite, residual delta-ferrite with various morphologies, reversed austenite and chromium carbides. The reversed austenite, which can be detected through both EBSD and XRD techniques, was found to be finely dispersed along the martensite lath boundaries, particularly at triple junctions. Based on the EBSD analysis, the orientation relationship between the reversed austenite and the adjacent martensite laths seemed to follow the Kurdjumov-Sachs (K-S) model. The results also revealed the presence of the reversed austenite in the different regions of the heat affected zone after post-weld tempering. The microindentation hardness distribution was measured, and correlated to the evolution of the corresponding microstructure across the welds. - Highlights: •The EBSD analysis was performed on hybrid laser-arc welded CA6NM. •The FZ consisted of tempered lath martensite, reversed austenite, carbides and δ ferrite after tempering. •The reversed γ was formed along the α′ lath boundaries, particularly at triple junctions.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Effect of Solutionizing Time on Improving the Microstructure and Mechanical Properties of Aged AZ80 Mg Alloy

The effects of solutionizing soak time and aging on the microstructure and mechanical properties of cast AZ80 Mg alloy were investigated. Optical microscopy, scanning electron microscopy and x-ray diffraction revealed the dissolution of β-Mg{sub 17}Al{sub 12} phase in the solution-treated samples which was later detected in the aged condition. Solution treatments at 420 °C for 4-16 h with water quenching followed by aging at 200 °C for 10 h were carried out, causing discontinuous precipitates to be formed with different precipitate morphologies at the various soak times. The discontinuous precipitates were observed to transform from the interdendritic segregation to parallel lamellae with increasing soak time to 8-10 h. As the soak time increased to 16 h, parallel lamellae transformed into tree-like precipitate morphology. The results showed significant changes in the interlamellar spacing at different soak times, and such precipitate morphology could influence the microstructure and mechanical properties after the aging process. A good combination of strength and ductility was obtained when the cast AZ80 Mg alloy was solution-treated at 420 °C for 10 h and aged at 200 °C for 10 h. Compared to the as-cast condition, a significant increase in ultimate tensile strength (50%), yield strength (47%) and elongation (43%) were observed.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Microstructural characterization of an SA508–309L/308L–316L domestic dissimilar metal welded safe-end joint

The microstructure of an SA508–309L/308L–316L domestic dissimilar metal welded safe-end joint was characterized in this work by optical microscopy, scanning electron microscopy (with electron back scattering diffraction) and micro-hardness testing. Epitaxial growth and competitive growth are evident in the 308L–316L fusion boundary regions. A martensite layer, carbon-depleted zones, and type-II and type-I boundaries are found in the SA508–309L fusion boundary regions, while only martensite and austenite mixed zones are observed in the SA508–308L fusion boundary regions. The microstructure near the fusion boundary and the microstructure transition in the SA508 heat affected zone are quite complex. Both for SA508–309L/308L and 308L–316L, the highest residual strain is located on the outside of the weldment. The residual strain and the grain boundary character distribution change with increasing distance from the fusion boundary in the heat affected zone of 316L. Micro-hardness measurements also reveal non-uniform mechanical properties across the weldment. - Highlights: • The microstructure of SA508 HAZ, especially near the FB, is very complex. • The outside of the dissimilar metal welded joint has the highest residual. • The micro-hardness distributions along the DMWJ are non-uniform.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Effect of Cobalt on the Microstructure and Corrosion Behavior of Martensitic Age-Hardened Stainless Steel

To evaluate the influence of cobalt on the microstructure and pitting behavior of martensitic age-hardened stainless steel (MASS), the microstructures and electrochemical behaviors were characterized by optical microscopy, scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, potentiodynamic curve, electrochemical impedance spectroscopy, and Mott–Schottky analysis. Results indicated that adding cobalt reduced the grain size of the original austenite, refined the lath martensite, inhibited the precipitation of Cu-rich phases, and increased the content of reversed austenite. Compared with the cobalt-free steel, the cobalt-containing steel has a higher pitting potential, lower corrosion current density, and higher pitting resistance. The primary components of the passive film grown on the cobalt-free steel included (Cr, Fe) oxides, such as Cr{sub 2}O{sub 3}, Cr(OH){sub 3}, FeOOH, and Fe{sub 2}O{sub 3}. The cobalt-containing steel included the aforementioned components as well as Co, which was attributed to the formation of the passive film in the forms of CoFe{sub 2}O{sub 4}, Co(OH){sub 2}, and CoO. In addition, the synergy of the refined lath martensite and the precipitation of the Cu-rich phase induced an increase in corrosion resistance in MASS containing cobalt.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Microstructure and microhardness of an Al-6061 metal matrix composite processed by high-pressure torsion

Disks of an Al-6061 metal matrix composite, reinforced with 10 vol.% Al{sub 2}O{sub 3} particles, were processed by high-pressure torsion (HPT) at room temperature for 1/4, 1/2, 1, 5 and 10 turns under an applied pressure of 6.0 GPa. The evolution of microstructure was investigated using optical microscopy and scanning electron microscopy. During HPT processing the average grain size within the aluminum matrix decreased from ∼ 35 μm in the unprocessed condition to ∼ 170 nm after processing through 10 turns but there was no significant effect on the size and distribution of the alumina particulate clusters. The values of the Vickers microhardness were recorded across the surface of each disk and then plotted as two-dimensional and three-dimensional color-coded contour maps. The results show the hardness increases from ∼ 56 Hv in the initial condition to ∼ 165 Hv after HPT for 10 turns. The results demonstrate that, as in many unreinforced metallic alloys, the evolution of hardness with strain exhibits strain hardening without any significant recovery. - Highlights: •The average grain size of the Al matrix was ~ 170 nm after processing for 10 turns. •No significant effect of HPT on the size and distribution of the Al{sub 2}O{sub 3} particles. •The evolution of microhardness demonstrates strain hardening without recovery. •The microhardness at low strains increases linearly from the center to the edge. •The microhardness at high strains becomes homogeneous with a saturation of ~ 170 Hv.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Metallurgical characterization of brass objects from the Akko 1 shipwreck, Israel

The Akko 1 shipwreck was a small Egyptian armed vessel or auxiliary naval brig built in the eastern Mediterranean at the beginning of the 19th century. During the underwater excavations, about 230 brass hook-and-eye closures were found, mainly in the bow area. In addition, 158 brass cases were found, mainly between midships and the aft extremity of the shipwreck. Metallurgical non-destructive and destructive characterizations of selected items were performed, including radiographic testing, XRF, lead isotope analysis, optical microscopy, SEM–EDS and microhardness tests. The hook-and-eye closures and the cases were both found to be made of binary copper–zinc alloy (about 30 wt.% zinc). While the brass cases were made from rolled sheets, hand-made using simple tools, and joined by tin–lead soldering material, the brass hook-and-eye closures were hand-made from drawn brass wire, and manufactured from commercial drawn brass bars by a cold-working process. The lead isotope analyses suggest different provenances of the raw materials used for making the brass objects, thus the different origins of the ores may hint that the brass wire and sheet were imported to the workshops in which the objects were manufactured. - Highlights: • Brass cases and hook-and-eye closures were retrieved from the Akko 1 shipwreck. • Both types of objects were made of binary copper–zinc alloy (about 30 wt.% zinc). • The cases were hand-made from rolled sheets and joined by tin–lead soldering. • Hook-and-eye closures were made from drawn brass wire manufactured by cold-working. • Lead isotope analyses suggest that the origins of the raw material were diverse.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Evolution mechanisms of the primary α and β phases during α/β deformation of an α/β titanium alloy TC8

A TC8 titanium alloy was isothermally compressed at the strain rates of 10–50 s{sup −1} in the two-phase region of 820–940 °C, and the evolution mechanisms of the primary α and β phases, including grain morphology, dynamic recovery (DRV) and dynamic recrystallization (DRX), were investigated by optical microscopy (OM) and transmission electron microscopy (TEM). OM reveals that the phase content and grain morphology are more significantly influenced by the deformation temperature than the strain rate. The β grains achieve refinement only at 940 °C due to DRX in the β phase. TEM reveals the remarkable variations of the DRX grains, subgrains, sub-boundaries and dislocations morphology with temperature and strain rate related to DRV and DRX in the primary α phase. The DRX in the primary α phase appears most strongly at a middle temperature of 860 °C, and DRV dominates in the primary α phase at 940 °C. While the dominant mechanism varies from DRV to DRX in the β phase as the temperature increases. Finally, the influence mechanism of deformation parameters on the primary α grain morphology is revealed based on the combined effect of DRV and DRX in the primary α phase and diffusion of the β phase. - Highlights: •The β grains achieve refinement only at 940 °C due to DRX in the β phase. •The DRX in the primary α phase is most remarkable at 860 °C. •The dominant mechanism in β phase varies from DRV to DRX with increasing temperature. •The interaction between the primary α and β phases depends on the phase content.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Study on Texture Evolution and Shear Behavior of an Al/Ni/Cu Composite

The microstructure, texture, and mechanical properties of the Al/Ni/Cu composite during various accumulative roll bonding (ARB) cycles were studied using optical microscopy, scanning electron microscopy, x-ray diffraction, shear punch test, and hardness test. In addition, ImageJ software and Rietveld software were used in order to study microstructure and dislocation density variations, respectively. It was found that Ni and Cu layers were fractured and distributed in the Al matrix due to differences in their mechanical properties. Fracture and distribution of Cu and Ni particles after cycle five led to the alteration of the composite structure from a layered to a particle-reinforced structure. ARB process leads to the formation of strong orientation along the β-fiber and also to pronounced copper and dillamore components in both Al and Cu phases. Furthermore, the shear yield stress and ultimate shear strength of the composite increased as the ARB process advanced; however, shear elongation presented a non-uniform variation. Investigation of the fracture surfaces revealed that the mechanical properties of the composite are affected not only by the strain hardening of the Cu layer, but also by the structural change in the composite during the initial ARB cycles. During the last stages of the process, however, changes in mechanical properties were mostly governed by reinforcement particles serving as strain concentration zones and the strain hardening of the Al matrix.

36 MATERIALS SCIENCE↗
DOE OSTI2014

The microstructure and mechanical behaviors of the Ti–6.5Al–3.5Mo–1.5Zr–0.3Si alloy produced by laser melting deposition

The microstructure and mechanical properties of the Ti–6.5Al–3.5Mo–1.5Zr–0.3Si alloy produced by laser melting deposition have been investigated. The columnar grains of the Ti–6.5Al–3.5Mo–1.5Zr–0.3Si alloy due to the layer-by-layer epitaxial growth from the underlying template grains during laser melting deposition, which is roughly parallel to the deposition direction, had been found by optical microscopy; strong [101{sup ¯}2]{sub α} crystallographic texture has been confirmed by X-ray diffraction and electron backscattered diffraction. Depending on the last heating history, the microstructure of the alloy undergoes a continued change opposite to the deposition direction: martensitic α′ (transformed β); coarsened primary α laths with transformed β; coarsened primary α laths; and the fine basketweave microstructure with a few coarsened α laths or annealed martensitic α′. The average Vickers micro-hardness value of the alloy is 364 HV. The alloy parallel to the deposition direction presents lower tensile strength (925 MPa) and better elongation (18.8%), compared with 1025 MPa and 8.2% of that vertical to the deposition direction, which has been discussed using its microstructure characterization. - Highlights: • The columnar grains and strong [101{sup ¯}2]{sub α} crystallographic texture of the Ti–6.5Al–3.5Mo–1.5Zr–0.3Si alloy due to the epitaxial growth from the underlying template grains • The microstructure evolution of the alloy depends on the last heating history. • The specimen parallel to the deposition direction presents lower ultimate tensile strength and higher elongation than the specimen vertical to the deposition direction.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Nanostructured self-assembly materials from neat and aqueous solutions of C18 lipid pro-drug analogues of Capecitabine—a chemotherapy agent. Focus on nanoparticulate cubosomes™ of the oleyl analogue

A series of prodrug analogues based on the established chemotherapy agent, 5-fluorouracil, have been prepared and characterized. C18 alkyl and alkenyl chains with increasing degree of unsaturation were attached to the N 4 position of the 5-fluorocytosine (5-FC) base via a carbamate bond. Physicochemical characterization of the prodrug analogues was carried out using a combination of differential scanning calorimetry, cross-polarized optical microscopy, X-ray diffraction and small-angle X-ray scattering. The presence of a monounsaturated oleyl chain was found to promote lyotropic liquid crystalline phase formation in excess water with a fluid lamellar phase observed at room temperature and one or more bicontinuous cubic phases at 37 °C. The bulk phase was successfully dispersed into liposomes or cubosomes at room and physiological temperature respectively. In vitro toxicity of the nanoparticulate 5-FCOle dispersions was evaluated against several normal and cancer cell types over a 48 h period and exhibited an IC 50 of -100 μM against all cell types. The in vivo efficacy of 5-FCOle cubosomes was assessed against the highly aggressive mouse 4T1 breast cancer model and compared to Capecitabine (a water-soluble commercially available 5-FU prodrug) delivered at the same dosages. After 21 days of treatment, the 0.5 mmol 5-FCOle treatment group exhibited a significantly smaller average tumour volume than all other treatment groups including Capecitabine at similar dosage. These results exemplify the potential of self-assembled amphiphile prodrugs for delivery of bioactives in vivo.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Compatibility of molten plutonium with wrought and additively manufactured metal crucibles

Understanding plutonium’s interaction with metals is crucial for optimizing pyrochemical operations, nuclear fuel containment, and various actinide processing techniques. Traditionally, tantalum crucibles are employed for plutonium processing due to their high durability, excellent temperature stability, and low solubility in plutonium. However, tantalum faces challenges such as plutonium wetting and diffusion, making surface coatings particularly important for crucibles in pyrochemical applications to enhance corrosion resistance against plutonium. Tantalum is also expensive and difficult to machine, prompting the need for advanced manufacturing techniques to address these challenges. Here, in this work, we investigate the interaction of Pu with tantalum and titanium crucibles fabricated using both traditional machining methods and laser powder bed fusion (LPBF) additive manufacturing (AM). LPBF-AM is an advanced technique that allows for the creation of complex geometries from traditionally difficult-to-machine metals by using a high-powered laser to build parts. Previous studies of conventional manufactured tantalum have utilized oxidation and carburization of the surface to mitigate plutonium wetting; however, no studies of surface modified LPBF-AM material have been undertaken. These studies are crucial, given the typical differences in the grain structure between conventional and LPBF-AM materials. All crucibles underwent differential scanning calorimetry to confirm the melting of plutonium. Subsequently, the crucibles were sectioned and mounted in epoxy for microstructural analysis using optical microscopy and scanning electron microscopy. This investigation, comparing the performance of wrought vs AM metal crucibles, provides a basis for future tooling applications in actinide processing techniques and can address the challenges associated with traditional machining, particularly in pyrochemical applications.

Actinides↗