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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Corrosion study of bare and coated stainless steel

A program was conducted at Kennedy Space Center from February 1968 to February 1971 to evaluate the performance of austenitic stainless steel alloys used in fluid systems lines. For several years, there had been numerous failures of stainless steel hardware caused by pitting and stress corrosion cracking. Several alloys were evaluated for effectiveness of certain sacrificial-type protective coverings in preventing corrosion failures. Samples were tested in specially designed racks placed 91 meters (100 yards) above high-tide line at Cape Kennedy. It is concluded that: (1) unprotected tubing samples showed evidence of pitting initiation after 2 weeks; (2) although some alloys develop larger pits than others, it is probable that the actual pitting rate is independent of alloy type; (3) the deepest pitting occurred in the sheltered part of the samples; and (4) zinc-rich coatings and an aluminum-filled coating have afforded sacrificial protection against pitting for at least 28 months. It is believed that a much longer effective coating life can be expected.

Morrison, J. D.↗
NASA NTRS1979

Mechanical properties and oxidation and corrosion resistance of reduced-chromium 304 stainless steel alloys

An experimental program was undertaken to identify effective substitutes for part of the Cr in 304 stainless steel as a method of conserving the strategic element Cr. Although special emphasis was placed on tensile properties, oxidation and corrosion resistance were also examined. Results indicate that over the temperature range of -196 C to 540 C the yield stress of experimental austenitic alloys with only 12 percent Cr compare favorably with the 18 percent Cr in 304 stainless steel. Oxidation resistance and in most cases corrosion resistance for the experimental alloys were comparable to the commercial alloy. Effective substitutes for Cr included Al, Mo, Si, Ti, and V, while Ni and Mn contents were increased to maintain an austenitic structure.

Stephens, J. R.↗
NASA NTRS1976

Cross sections for He and Ne isotopes in natural Mg, Al, and Si, He isotopes in CaF2, Ar isotopes in natural Ca, and radionuclides in natural Al, Si, Ti, Cr, and stainless steel induced by 12- to 45-MeV protons

Stacks of thin Mg, Al, Si, Ca, CaF2, Ti, and stainless steel foils were bombarded in twelve irradiations by a variable energy cyclotron. Cross sections are reported for He and Ne in natural Mg, Al, and Si, and for He in CaF2, and for Ar in natural Ca, as determined from mass spectrometer analysis of the inert gases. In addition, cross sections of Na-22 in natural Al and Si, of V-48 in natural Ti, and of Cr-51, Mn-52, and Co-57 in stainless steel are reported. From these were deduced Cr-51 and Mn-52 cross sections in natural Cr.

Walton, J. R.↗
NASA NTRS1976

Diffusion brazing nickel-plated stainless steel

To bond parts, sandwich assembly is made up of aluminum core, aluminum face sheet with brazing alloy interface, and nickel plated stainless steel part. Sandwich is placed between bottom and top glide sheet that is placed in stainless steel retort where assembly is bonded at 580 C.

Beuyukian, C. S.↗
DOE OSTI2025

Tailoring composition and deformation modes at the microstructural level for next generation low-cost high-strength austenitic stainless steels

The objective of this project is to enable deliberate development of cost-effective, hydrogen resistant alloys by establishing detailed relationships specific to the effects of alloy composition, short-range order (SRO), and microsegregation in the presence of hydrogen on the transition between homogeneous deformation and localized plasticity in shear bands. In collaboration with the International Institute for Carbon-Neutral Energy Research, I2CNER, at Kyushu University in Japan, we conceptualized, designed, and manufactured four austenitic alloys that maintain corrosion resistance and ensure lower cost relative to baseline commercial alloys. The mechanical properties and deformation modes of the novel alloys (KU alloys) were assessed in the presence of hydrogen (H). Correlations between composition and performance revealed that two of the KU alloys are suitable replacements for 316 steel, while another is a viable replacement for 304 steel at room temperature. We found that, in the presence of other austenite stabilizing elements namely Mn and N, replacing Ni with Cu does not lead to martensite formation as has been previously reported.1–3 Furthermore, we found that the addition of Cu leads to an earlier onset of multiple slip resulting in an relative earlier onset of a higher work hardening rate (WHR). Greater understanding of the relationships between alloy composition and SRO required the development of a novel advanced electron diffraction methodology to characterize SRO in complex FCC alloys. This innovative approach, which combines fluctuation and correlation analyses of diffuse-scattering signals, successfully differentiated between SRO and long-range ordering (LRO). Further investigations into annealed austenitic stainless steels could provide insights into manipulating SRO and its effects on material properties. Atomistic simulations provided understanding of SRO behavior that was difficult to capture experimentally. This project created the first spin cluster expansion model that is able to capture and describe SRO effects in Fe-Ni-Cr FCC alloys, accounting for the non-negligible effects of magnetism. An automated computational workflow was established to provide reliable predictions of SRO in Fe-Ni-Cr austenitic alloys, both with and without the presence of H atoms. Analysis of the propensity for SRO in Fe-Ni-Cr alloys revealed that H tends to cluster with specific, well-defined SRO domains. The computational framework is general purpose and can be extended to realistic stainless steels across diverse composition ranges. With confidence that SRO is possible in austenitic stainless steels, we developed a discrete dislocation finite element code to understand the interaction of dislocations with SRO in the presence of H. By incorporating H effects on the dislocation emission and SRO stress field we show that the critical stress for the dislocation pileup to breakthrough the SRO domain decreases in the presence of H, which directly contributes localized deformation at the macroscale. Through the simulation of a uniaxial tension test, we demonstrated that H-induced weakening of SRO stress field and H-enhanced dislocation emission can lead to the onset of shear localization at lower macroscopic strains. As a whole, this project identified three novel alloys that show improvements in performance and cost efficiency for H-facing applications by studying correlations between alloy chemistry and deformation behavior. We also made significant advancements to experimental and computational methodologies necessary to study the chemistry and distribution of SRO across a range of alloys, which in turn allowed us to demonstrate how deformation mechanisms change due to the contributions of SRO in austenitic alloys in the presence of H. The combined advancements in fundamental understanding with novel alloy development in this project has increased the viability of next generation H-technologies for the broader public through accessible low-cost alloys and accelerated development towards future H-infrastructure.

08 HYDROGEN↗
DOE OSTI2025

Long-term thermal aging behavior and strength reduction in a laser powder bed fusion 316H stainless steel

The long-term thermal stability of structural alloys is essential for ensuring the safe and reliable operation of nuclear reactors and other power plants. While extensive research has explored the effects of thermal aging on conventional stainless steels, the behavior of additively manufactured (AM) alloys remains less understood. This study examines the thermal aging response of laser powder bed fusion (LPBF) 316H stainless steel (SS) at temperatures ranging from 550 °C to 750 °C over durations of up to 10,000 h (approximately 1.14 years). Advanced characterization techniques, including electron microscopy and synchrotron X-ray diffraction, were used to investigate dislocation recovery and phase evolution. Based on these findings, a time-temperature-precipitation (TTP) diagram was developed for LPBF 316H SS, revealing a 10- to100-fold acceleration in precipitation kinetics compared to wrought 316H SS. A physics-informed model was calibrated using the short-term experimental data, enabling predictions of average precipitate sizes, volume fractions of M 23 C 6 and Laves phases, and changes in molybdenum solute concentration for aging up to 1 × 10⁶ h (114 years). These microstructural insights were further utilized to estimate yield strength and extrapolate strength reduction factors over the extended aging period. Despite the accelerated aging kinetics, LPBF 316H SS demonstrated superior yield strength retention compared to its wrought counterpart. In conclusion, this study establishes a framework for evaluating long-term performance using short-term experimental data and supports the accelerated qualification of AM materials for high-temperature structural applications.

Laser powder bed fusion↗
NASA NTRS1990

A porous stainless steel membrane system for extraterrestrial crop production

A system was developed in which nutrient flow to plant roots is controlled by a thin (0.98 or 1.18 mm) porous (0.2 or 0.5 microns) stainless steel sheet membrane. The flow of nutrient solution through the membrane is controlled by adjusting the relative negative pressure on the nutrient solution side of the membrane. Thus, the nutrient solution is contained by the membrane and cannot escape from the compartment even under microgravity conditions if the appropriate pressure gradient across the membrane is maintained. Plant roots grow directly on the top surface of the membrane and pull the nutrient solution through this membrane interface. The volume of nutrient solution required by this system for plant growth is relatively small, since the plenum, which contains the nutrient solution in contact with the membrane, needs only to be of sufficient size to provide for uniform flow to all parts of the membrane. Solution not passing through the membrane to the root zone is recirculated through a reservoir where pH and nutrient levels are controlled. The size of the solution reservoir depends on the sophistication of the replenishment system. The roots on the surface of the membrane are covered with a polyethylene film (white on top, black on bottom) to maintain a high relative humidity and also limit light to prevent algal growth. Seeds are sown directly on the stainless steel membrane under the holes in the polyethylene film that allow a pathway for the shoots.

NASA Discipline Number 61-20↗
DOE OSTI2024

First-principles and cluster expansion study of the effect of magnetism on short-range order in Fe–Ni–Cr austenitic stainless steels

Short-range order (SRO), the regular and predictable arrangement of atoms over short distances, alters the mechanical properties of technologically relevant structural materials such as medium/high entropy alloys and austenitic stainless steels. In this study, we present a generalized spin cluster expansion (CE) model and show that magnetism is a primary factor influencing the level of SRO present in austenitic Fe-Ni-Cr alloys. The spin CE consists of a chemical cluster expansion combined with an Ising model for Fe-Ni-Cr austenitic alloys. It explicitly accounts for local magnetic exchange interactions, thereby capturing the effects of finite temperature magnetism on SRO. Model parameters are obtained by fitting to a first-principles data set comprising both chemically and magnetically diverse FCC configurations. The magnitude of the magnetic exchange interactions are found to be comparable to the chemical interactions. Compared to a conventional implicit magnetism CE built from only magnetic ground state configurations, the spin CE shows improved performance on several experimental benchmarks over a broad spectrum of compositions, particularly at higher temperatures due to the explicit treatment of magnetic disorder. We find that SRO is strongly influenced by alloy Cr content, since Cr atoms prefer to align antiferromagnetically with nearest neighbors but become magnetically frustrated with increasing Cr concentration. Using the spin CE, we predict that increasing the Cr concentration in typical austenitic stainless steels promotes the formation of SRO and increases order-disorder transition temperatures. Furthermore, this study underscores the significance of considering magnetic interactions explicitly when exploring the thermodynamic properties of complex transition metal alloys. It also highlights guidelines for customizing SRO through adjustments of alloy composition.

36 MATERIALS SCIENCE↗
NASA NTRS1977

Oxidation and corrosion behavior of modified-composition, low-chromium 304 stainless steel alloys

The effects of substituting less strategic elements than Cr on the oxidation and corrosion resistance of AISI 304 stainless steel were investigated. Cyclic oxidation resistance was evaluated at 870 C. Corrosion resistance was determined by exposure of specimens to a boiling copper-rich solution of copper sulfate and sulfuric acid. Alloy substitutes for Cr included Al, Mn, Mo, Si, Ti, V, Y, and misch metal. A level of about 12% Cr was the minimum amount of Cr required for adequate oxidation and corrosion resistance in the modified composition 304 stainless steels. This represents a Cr saving of at least 33%. Two alloys containing 12% Cr and 2% Al plus 2% Mo and 12% Cr plus 2.65% Si were identified as most promising for more detailed evaluation.

Stephens, J. R.↗
NASA NTRS2017

Cryogenic Thermal Emittance Measurements on Small-Diameter Stainless Steel Tubing

The Mid Infrared Instrument aboard the James Webb Space Telescope includes a mechanical cryocooler which cools its detectors to their 6 K operating temperature. The refrigerant flows through several meters of 2 mm diameter 304L stainless steel tubing, with some sections gold plated, and some not, which are exposed to their environment. An issue of water freezing onto the tube surfaces is mitigated by running a warm gas through the lines to sublimate the frozen water. To model the effect of this process on nearby instruments, an accurate measure of the tube emittance is needed. Previously we reported the absorptance of the gold plated stainless steel tubing as a function of source temperature (i.e. its environment). In this work the thermal emittance of the uncoated tubing is measured as a function of its temperature between 100 and 280 K. These values lead to an accurate prediction of the minimum length of time required to thermally recycle the system. We report the technique and present the results.

stainless steel↗
NASA NTRS2017

Cryogenic Thermal Emittance Measurements on Small-Diameter Stainless Steel Tubing

The Mid Infrared Instrument aboard the James Webb Space Telescoep includes a mechanical cryocooler which cools its detectors to their 6 K operating temperature. The refrigerant flows through several meters of approximately 2 mm diameter 304L stainless steel tubing, with some sections gold plated, and some not, which are exposed to their environment. An issue of water freezing onto the tube surfaces is mitigated by a running a warm gas through the lines to sublimate the water. To model the effect of this process on nearby instruments, an accurate measure of the tube emittance is needed. Previously we reported the abosprtance of the gold plated stainless steel tubing as a function of source temperature (i.e. its environment). In this work the thermal emittance of the uncoated tubing is measured as a function of its temperature between 100 and 300 K. This value leads to an accurate prediction of the minimum length of time required to thermally recycle the system. We report the technique and present the results.

cryogenic↗