Search NASA⌕ Search

Engineering topics

Materials science

Explore NASA and DOE materials research. Search alloys, composites and material properties, then open the original technical report for test conditions and results.

Follow this topic with RSS
At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Void swelling of conventional and composition engineered HT9 alloys after high-dose self-ion irradiation

Ferritic/martensitic (F/M) steels are being considered as potential structural materials for next generation nuclear reactors, and variants of the alloy HT9 are some of the most promising candidates. In this study, two conventional and two composition engineered HT9 alloys were irradiated using 3.5 MeV Fe 2+ up to 600 peak displacement-per-atom (dpa) at 450 °C. Void swelling and microstructure evolution were characterized for each alloy and compared. The two conventional HT9 alloys (INL and ACO3) showed similar void swelling behavior due to their similar elemental composition and processing conditions. The INL HT9 exhibited a maximum of 2.4% swelling and the ACO3 HT9 showed a maximum of 2.8% swelling at 342 and 393 average local dpa, respectively. On the other hand, the two-composition engineered HT9 alloys with varying N contents (10 ppm for low N and 440 ppm for high N) showed disparate swelling behavior. The low N HT9 exhibited a maximum of 4.6% swelling, while the high N HT9 showed a maximum of 0.7% swelling at 342 average local dpa. Changes in the N content also affected Ni/Si rich G-phase formation. The low N HT9 showed a larger size and lower density of G-phase precipitates compared with the high N HT9 after 600 peak dpa irradiation. This study compares the void swelling behavior of the ion irradiated four current HT9 alloys to extremely high doses, with the void swelling data from neutron irradiated HT9 alloys. Furthermore, the comparison lends critical insights into how well these current alloys can withstand high neutron fluxes in future reactors, especially since the low N and high N HT9 alloys have never been exposed to such high doses before.

36 MATERIALS SCIENCE↗
NASA NTRS1990

Solid state processing for high temperature alloys and composites

A variety of solid state powder processing methods have been examined for their potential to produce high temperature materials. These techniques included solid state diffusion, mechanical alloying, reaction milling, and exothermic reactions. While both mechanical alloying and exothermic reactions are capable of producing high temperature composites in addition to yielding solid solution and precipitation hardened alloys, reaction milling can only be used to make composite materials. Although at present this method has only been applied to make carbide strengthened Al, recent work indicates that reaction milling is capable of yielding high strength NiAl-AlN composites.

Whittenberger, J. Daniel↗
DOE OSTI2025

The effect of composition on helium bubble nucleation in complex concentrated alloys

Molecular dynamics simulations of helium implantation have been performed in the MoNbTaTi complex concentrated alloy (CCA) to determine the impact of composition on helium clustering and bubble nucleation. It was found that compositions with lower interstitial atomic volume resulted in smaller cluster sizes, higher helium-to-vacancy ratios, and larger migration barriers. As the atomic volume decreases, it is harder to accommodate additional helium in the lattice and for helium to diffuse between interstitial sites, resulting in smaller cluster sizes. In particular, increasing molybdenum directly correlated with a decreased interstitial atomic volume and increased migration barrier. Niobium exhibited the opposite trend, where more niobium in the material resulted in larger interstitial atomic volumes and cluster sizes but lower migration barriers. The atomic volume was determined to be an indicator of the susceptibility of the material to helium bubble growth and could potentially be used as a metric to screen compositions for resistance to helium damage. In this way, properties such as available interstitial volumes could be used to screen materials more rapidly given the vast compositional space of CCAs.

McCarthy, Megan Jeanne [Sandia National Laboratori↗
NASA NTRS1993

Surface compositional variations of Mo-47Re alloy as a function of temperature

Molybdenum-rhenium alloys are candidate materials for the National Aero-Space Plane (NASP) as well as for other applications in generic hypersonics. These materials are expected to be subjected to high-temperature (above 1200 C) casual hydrogen (below 50 torr), which could potentially degrade the material strength. Since the uptake of hydrogen may be controlled by the contaminant surface barriers, a study of Mo-47Re was conducted to examine the variations in surface composition as a function of temperature from 25 C to 1000 C. Pure molybdenum and rhenium were also examined and the results compared with those for the alloy. The analytical techniques employed were Auger electron spectroscopy, electron energy loss spectroscopy, ion scattering spectroscopy, and x ray photoelectron spectroscopy. The native surface was rich in metallic oxides that disappeared at elevated temperatures. As the temperature increased, the carbon and oxygen disappeared by 800 C and the surface was subsequently populated by the segregation of silicon, presumably from the grain boundaries. The alloy readily chemisorbed oxygen, which disappeared with heating. The disappearance temperature progressively increased for successive dosings. When the alloy was exposed to 800 torr of hydrogen at 900 C for 1 hour, no hydrogen interaction was observed.

Hoekje, S. J.↗
DOE OSTI2022

Alloying of Pu-Al with Stainless Steel for Material Disposition

The Savannah River National Laboratory (SRNL) has evaluated several options for the disposition of stainless-steel clad plutonium metal alloy. One of the technologies under consideration is alloying of the material with stainless steel (SS). The resulting SS-Pu alloy would be a non-proliferable waste form consisting of a secondary Pu composition region microencapsulated in the refractory stainless steel. Two 8-kg ingots were made at SS-1.8Zr-0.4Pu alloys (wt %); 8 kg was determined in a previous study to be the maximum mass of SS ingot at the maximum target Pu loading of 350-g that would result in a SS-4.4Pu alloy (wt %). Two smaller 500-g ingots were also produced at SS-1.6Zr-1.4Pu and SS-1.4Pu (wt %). The 500-g ingots evaluated alloying at a higher Pu concentration than in the 8 kg ingots, and they evaluated the necessity of adding Zr metal to incorporate the Pu and control Pu oxidation. Zr addition was found to be unnecessary to incorporate the Pu and control Pu oxidation. Drill turnings were collected from the large and small ingots and metallographic samples were directly cut from the small ingots. Both were analyzed to validate the structure and composition region formation. Chemical analyses of turnings proved that the Pu was dispersed within the SS ingots.

36 MATERIALS SCIENCE↗
DOE OSTI2023

High‐Throughput Computational Guided Development of Refractory Complex Concentrated Alloys‐based Composite

ULTIMATE is a leading-edge DOE program to develop ultrahigh temperature materials for gas turbine use in the aviation and power generation industries. This team, headquartered at West Virginia University and including collaborators from the National Energy Technology Laboratory and Advanced Manufacturing LLC, has developed a new class of ultra-high temperature Refractory Complex Concentrated Alloys-based Composites (RCCC) for high temperature applications such as combustion turbines used in the aerospace and energy industries. The RCCC consist of Refractory Complex Concentrated Alloys (RCCA) mixed with particles of Refractory High Entropy Carbides, to increase RCCA strength to withstand extreme conditions. These new materials optimize the balance among strength, creep (deformation), density, and stability at 1300 °C (2372 °F), while maintaining ductility once the alloy cools to room temperature. The research team has developed advanced manufacturing processes using the pulsed electric current and laser 3D printing to produce test coupons of these materials.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Development of HPC based phase field simulations tool for modification of alloy morphology to enhance material properties during additive manufacturing (AM) process

Currently, additive manufacturing (AM) technology is extensively used to manufacture aerospace components because of the unique advantages of the technique in producing custom designs, complex geometries in a near-net fashion that significantly reduces the manufacturing cost, and improved energy efficiency. However, the thermodynamic properties of existing aerospace alloys and the thermal conditions that prevail in most of the powder-bed based additive manufacturing processes lead to undesirable columnar / columnar-dendritic microstructures that promote solidification cracking during the process, and the development of anisotropy in the mechanical properties of the as-built components. Time consuming, energy-intensive post AM treatments are required to recover the mechanical properties of the wrought components for which the existing alloy compositions were designed for. However, novel alloy compositions, that exploit the AM thermal conditions to produce fine, equiaxed grain structures in the as-built condition, with mechanical properties equal to or exceeding those of the wrought work-horse alloy, Ti-6Al-4V has recently been demonstrated in Ti-Cu alloys. Significant energy savings up to 66% can be obtained for a typical aerospace component through digitally designing the AM process, process parameters, and alloy composition. The current project focused on developing a fundamental understanding of the evolution of the columnar to equiaxed transition (CET) occurring during solidification under AM thermal conditions in Ti-Cu and Ti-Cu-X alloys using high-fidelity phase field (PF) simulations using the leadership class computing facilities that exist in the national laboratories. The simulations were able to capture the effect of alloy and process conditions on CET, and clearly showed the beneficial effect of a ternary solute addition to Ti-Cu binary alloys on CET. The simulations indicated that bulk nucleation in the liquid ahead of the solidifying epitaxial front was promoted by a large, transient, thermal undercooling promoted by the mismatch between the growth rate of the dendrite tips in the epitaxial front and the imposed solidification rate. AM experiments performed at Raytheon Technologies Research Center using the same thermal conditions used in the PF simulations indicated the formation of equiaxed grains, although the grain size was bigger than the ones reported in the literature. On the other hand, the equiaxed grain size predicted by PF simulations were smaller than the grain size of Ti-Cu alloys reported in the literature. The industry will follow up the existing work in a future program that would involve further optimization of the process for the Ti-Cu-X alloys to demonstrate the application of the process and the alloy to a specific aerospace component.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Phase stabilization and oxidation of a continuous composition spread multi-principal element (AlFeNiTiVZr) 1-x Cr x alloy

Multi-Principal Element Alloys (MPEA) have been hypothesized to maintain a stable single alloy phase and resist corrosion at high temperatures, which are desirable in various functional applications, including material of turbine blades. However, studies into oxidation resistant alloys have been constrained to individual MPEA systems or a limited selection of compositions within those systems. Here, High-Throughput Experimental (HTE) techniques were utilized to rapidly assess phase stability and resistance to oxidation of an (AlFeNiTiVZr) 1-x Cr x continuous composition spread (CCS) thin-film alloy system. High-throughput synchrotron diffraction and Raman spectroscopy were used to identify phases, especially high symmetry structures and oxides, as a function of annealing time and composition. The formation of two distinct phase regions, R 1 and R 2 , across the CCS was observed. One of these phase regions, R 2 , exhibited a stable high symmetry BCC-like phase at Cr concentrations greater than 25.4 at%, and grew a passivating mixed metal surface oxide; whereas, the R 1 phase region, decomposed on oxidation to multiple oxides and reacted with the substrate to form silicides. The passivating mixed metal oxide layer appears to prevent destabilization of the (AlFeNiTiVZr) 1-x Cr x MPEA BCC solid solution. Furthermore, at longer annealing times the passivating phase was seen only above 29.2 at% Cr. High Cr-doped (AlFeNiTiVZr) 1-x Cr x appear to be a good candidate for high temperature, oxidation-resistant structural alloys.

36 MATERIALS SCIENCE↗
NASA NTRS1992

Composite materials for the extravehicular mobility unit

The extravehicular mobility unit (EMU), commonly known as the astronaut space suit assembly (SSA) and primary life support system (PLSS), has evolved through the years to incorporate new and innovative materials in order to meet the demands of the space environment. The space shuttle program which is seeing an increasing level of extravehicular activity (EVA), also called space walks, along with interest in an EMU for Lunar-Mars missions means even more demanding conditions are being placed on the suit and PLSS. The project for this NASA-ASEE Summer Program was to investigate new materials for these applications. The focus was to emphasize the use of composite materials for every component of the EMU to enhance the properties while reducing the total weight of the EMU. To accomplish this, development of new materials called fullerene reinforced materials (FRM's) was initiated. Fullerenes are carbon molecules which when added to a material significantly reduce the weight of that material. The Faculty Fellow worked directly on the development of the fullerene reinforced materials. A chamber for fullerene production was designed and assembled and first generation samples were processed. He also supervised with the JSC Colleague, a study of composite materials for the EMU conducted by the student participant in the NASA-ASEE Program, Hector Tello a Rice University graduate student, and by a NASA Aerospace Technologist (Materials Engineer) Evelyne Orndoff, in the Systems Engineering Analysis Office (EC7), also a Rice University graduate student. Hector Tello conducted a study on beryllium and Be alloys and initiated a study of carbon and glass reinforced composites for space applications. Evelyne Orndoff compiled an inventory of the materials on the SSA. Ms. Orndoff also reviewed SSA material requirements and cited aspects of the SSA design where composite materials might be further considered. Hector Tello spent part of his time investigating the solar radiation sensitivity of anodic coatings. This project was directed toward the effects of ultra-violet radiation on high emissivity anodic coatings. The work of both Evelyne Orndoff and Hector Tello is of interest to the Engineering Directorate at NASA/JSC and is also directed toward their research as Rice University graduate students.

Barrera, Enrique V.↗
NASA NTRSDate not supplied

Lightweight Thrust Chamber Assemblies using Multi-Alloy Additive Manufacturing and Composite Overwrap

Additive Manufacturing (AM) has brought significant design and fabrication opportunities for complex components with internal features such as liquid rocket engine thrust chambers not previously possible. This technology allows for significant cost savings and schedule reductions in addition to new performance optimization through weight reduction and increased margins. Specific to regeneratively-cooled combustion chambers and nozzles for liquid rocket engines, additive manufacturing offers the ability to form the complex internal coolant channels and the closeout of the channels to contain the high pressure liquid propellants with a single operation. Much of additive manufacturing development has focused on monolithic alloys using Laser Powder Bed Fusion (L-PBF), which do not allow for complete optimization of the structure. The National Aeronautics and Space Administration (NASA) completed feasibility of an AM bimetallic L-PBF GRCop-84 copper-alloy combustion chamber with an AM electron beam freeform Inconel 625 structural jacket under the Low Cost Upper Stage Propulsion (LCUSP) Project. A follow-on project called Rapid Analysis and Manufacturing Propulsion Technology (RAMPT) is under development to further expand large-scale multi-alloy thrust chambers while maturing composite overwrap technology for significant weight savings opportunities. The RAMPT project has three primary objectives: 1) Advancing blown powder Directed Energy Deposition (DED) to fabricate integral-channel large scale nozzles, 2) Develop composite overwrap technology to reduce weight and provide structural capability for thrust chamber assemblies, and 3) Develop bimetallic and multi-metallic additively manufactured radial and axial joints to optimize material performance. In addition to these primary manufacturing developments, analytical modeling efforts compliment the process development to simulate the AM processes to reduce build failures and distortions. The RAMPT project is also maturing the supply chain for various manufacturing processes described above in addition to L-PBF of GRCop-42. This paper will present an overview of the RAMPT project, the process development and hardware progress to date, material and hot-fire testing results, along with future developments.

Additive Manufacturing↗
DOE OSTI2020

Direct-Write Printing Copper–Nickel (Cu/Ni) Alloy with Controlled Composition from a Single Electrolyte Using Co-Electrodeposition

Although various processes for metal printing at the micro- and mesoscale have been demonstrated, printing functional devices such as thermocouples, thermopiles, and heat flux sensors that function based on interfaces between an alloy and another alloy/metal demands processes for printing alloys. Furthermore, a high-quality and crystalline alloy is required for acceptable function of these devices. This article reports for the first time co-electrodeposition-based printing of single-phase solid solution nanocrystalline copper/nickel (Cu/Ni) alloy with various controllable compositions (Cu100Ni0 to Cu19Ni81) from a single electrolyte. Additionally, the printed alloy is nanocrystalline (<35 nm), continuous, and dense with no apparent porosity, with remarkable mechanical and magnetic properties, without any postprocessing annealing such as heat treatment. In addition, a functional thermocouple fabricated using this process is demonstrated. Such a process can not only be used for fabrication of functional devices, it may also facilitate fundamental studies on alloys by printing a continuous library of alloy composition for material characterization.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Predicting path-dependent diffusion barrier spectra in vast compositional space of multi-principal element alloys via convolutional neural networks

The emergent multi-principal element alloys (MPEAs) provide a vast compositional space to search for novel materials for technological advances. How to screen promising compositions from such an ample design space for targeted properties is a grand challenge. In this report, we demonstrate the state-of-the-art deep learning technology—convolutional neural network (CNN)—in predicting path-dependent vacancy migration energy barrier spectra, which are critical to diffusion behavior and many high-temperature properties, in the hyperdimensional composition space of MPEAs. The developed CNN model, fully capturing local chemical features surrounding each vacancy, accurately and efficiently predicts migration energy barrier of MPEAs with different degrees of chemical short-range order and at any unseen compositions. By varying the size of the local region encapsulating vacancy in the CNN model, we reveal that the length scale influencing vacancy migration is surprisingly extensive, up to its six nearest neighboring shells. The efforts of the CNN model make it promising for developing a database of diffusion barriers for various MPEA systems, which would have profound implications for accelerating alloy screening and discovering new compositions with desirable properties.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Tuning the spin dynamics and magnetic phase transitions of the Cantor alloy via composition and sample processing protocols: A muon spin relaxation study

CrMnFeCoNi, also called the Cantor alloy, is a well-known high-entropy alloy whose magnetic properties have recently become a focus of attention. Here, we present a detailed muon spin relaxation study of the influence of chemical composition and sample processing protocols on the magnetic phase transitions and spin dynamics of several different Cantor alloy samples. Specific samples studied include a pristine equiatomic sample, samples with deficient and excess Mn content, and equiatomic samples magnetized in a field of 9 T or plastically deformed in pressures up to 0.5 GPa. The results confirm the sensitive dependence of the transition temperature on composition and demonstrate that post-synthesis pressure treatments cause the transition to become significantly less homogeneous throughout the sample volume. In addition, we observe critical spin dynamics in the vicinity of the transition in all samples, reminiscent of canonical spin glasses and magnetic materials with ideal continuous phase transitions. Application of an external magnetic field suppresses the critical dynamics in the Mn-deficient sample, while the equiatomic and Mn-rich samples show more robust critical dynamics. The spin-flip thermal activation energy in the paramagnetic phase increases with Mn content, ranging from 3.1⁢(3) × 10 -21 J for 0% Mn to 1.2⁢(2) × 10 -20 J for 30% Mn content. These results shed light on critical magnetic behavior in environments of extreme chemical disorder and demonstrate the tunability of spin dynamics in the Cantor alloy via chemical composition and sample processing.

36 MATERIALS SCIENCE↗
NASA NTRS1986

Impact and residual fatigue behavior of ARALL and AS6/5245 composite materials

Aramide fiber reinforced aluminum laminates (ARALL) represent a cross between resin matrix composites and metals. The purpose of this study was to evaluate the impact sensitivity of this concept. Two types of ARALL (7075 aluminum prestrained and 2024 aluminum not prestrained) were tested through static indentation and the results compared to sheet 2024-T3 and 7075-T6 aluminum alloys. A state-of-the-art composite (AS6/5245) was also tested and compared to the ARALL. Further, the two types of ARALL material and the composite were dynamically impacted at two energy levels and fatigue tested to determine residual fatigue strength. Both forms of the ARALL material had worse impact resistance than monolithic sheet aluminum. The ARALL material made with 2024-T3 aluminum had better impact resistance than did the laminates made with 7075-T6 aluminum. The ARALL materials are at least equal to the composite material in impact damage resistance and are better for impact detection. The composite material has higher residual fatigue strength after impact than the ARALL material and is 25 percent lighter. The prestraining of the ARALL greatly reduces the fatigue growth of impact damage.

Johnson, W. S.↗
DOE OSTI2024

Microstructural evolution of compositionally complex solid-solution alloys under in-situ dual-beam irradiation

Here, this work attempts to link the microstructural evolution of single-phase compositionally complex alloy (CCA) compositions under dual-beam irradiation to their Mn-content via the stacking-fault energy (SFE) and vacancy migration energies. Two alloys, Cr 18 Fe 27 Mn 27 Ni 28 and Cr 15 Fe 35 Mn 15 Ni 35 , along with less compositionally complex pure Ni and Fe 56 Ni 44 binary were irradiated at 500 and 600 °C under dual-beam 1 MeV Kr 2+ and 16 keV He + heavy-ions up to 7 displacements per atom (dpa) with a He/dpa ratio of 0.75 %/dpa using in situ transmission electron microscopy (TEM). Due to the bubble-stabilizing effect of implanted He, bubbles were observed in all irradiations, and populations of faulted interstitial loops were characterized in Cr 18 Fe 27 Mn 27 Ni 28 and Cr 15 Fe 35 Mn 15 Ni 35 . A reduction in swelling was observed in the two CCAs compared to pure Ni and Fe 56 Ni 44 . Although swelling increased from 500 to 600 °C in Fe 56 Ni 44 , Cr 15 Fe 35 Mn 15 Ni 35 and Cr 18 Fe 27 Mn 27 Ni 28 both swelled slightly more at 500 °C. This was attributed to the difference in vacancy mobility, stronger pinning effect of vacancies on He, and the sink strength of faulted dislocation loops. Faulted interstitial loops nucleated with a higher number density and dislocation line density in Cr 15 Fe 35 Mn 15 Ni 35 at both temperatures, and at 600 °C in both materials. The differences in faulted loop population and temperature effect on swelling are correlated to the Mn-content and the measured SFE (20.2 ± 6.7 mJ/m 2 for Cr 18 Fe 27 Mn 27 Ni 28 and 9.2 ± 3.4 mJ/m 2 for Cr 15 Fe 35 Mn 15 Ni 35 ).

36 MATERIALS SCIENCE↗
NASA NTRS1993

Casting of superconducting composite materials (M-4)

An aluminum-lead-bismuth alloy is a flexible alloy and is promising for easily workable embedded-type, filament-dispersed superconducting wire material. It is difficult to produce homogeneous ingots of this material because it is easily separated into elements when melted on Earth due to the large specific gravity differences. In this experiment, a homogeneous alloy will first be produced in molten state in microgravity. It will then be returned to Earth and processed into a wire or tape form. It will then be dispersed as the second phase in micro texture form into the primary phase of aluminum. Superconducting wire material with high-critical-magnetic-field characteristics will be produced. The texture of the material will be observed, and its performance will be evaluated. In addition to the above alloy, a four-element alloy will be produced from silver, a rare Earth element, barium, and copper. The alloys will be oxidized and drawn into wire after being returned to Earth. The materials are expected to be forerunners in obtaining superconducting wire materials from oxide superconductors.

Togano, Kazumasa↗
DOE OSTI2022

Developing ductile and isotropic Ti alloy with tailored composition for laser powder bed fusion

Laser powder bed fusion (LPBF) is an advanced technology to create metallic components with complex geometry. Ti-6Al-4V (Ti64) is one of the most frequently used materials for LPBF. The intrinsic high cooling rates and ultra-high directional thermal gradient of melt, however, lead to a hierarchical structure composed of fine martensitic alpha' within columnar prior-beta grains in LPBF Ti64. This microstructure results in poor ductility and strong mechanical anisotropy in as-built Ti64 components, which largely limit their applications. Here, we report that the above shortcomings can be overcome by tailoring the alloy composition. Specifically, by reducing the aluminum content from 6 wt% to 4 wt%, the resultant LPBF Ti-4Al-4V (Ti44) alloy exhibits substantially improved ductility and mechanical isotropy. These improvements are attributed to grain refinement during solidification and the activation of multiple slip modes and twinning in the as-built material during deformation. This work offers a simple strategy to design new titanium alloys for LPBF with significantly improved ductility and isotropy.

36 MATERIALS SCIENCE↗