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NASA NTRS2014

Preliminary Report on U-Th-Pb Isotope Systematics of the Olivine-Phyric Shergottite Tissint

Geochemical studies of shergottites suggest that their parental magmas reflect mixtures between at least two distinct geochemical source reservoirs, producing correlations between radiogenic isotope compositions, and trace element abundances.. These correlations have been interpreted as indicating the presence of a reduced, incompatible-element- depleted reservoir and an oxidized, incompatible-element-rich reservoir. The former is clearly a depleted mantle source, but there has been a long debate regarding the origin of the enriched reservoir. Two contrasting models have been proposed regarding the location and mixing process of the two geochemical source reservoirs: (1) assimilation of oxidized crust by mantle derived, reduced magmas, or (2) mixing of two distinct mantle reservoirs during melting. The former clearly requires the ancient martian crust to be the enriched source (crustal assimilation), whereas the latter requires a long-lived enriched mantle domain that probably originated from residual melts formed during solidification of a magma ocean (heterogeneous mantle model). This study conducts Pb isotope and U-Th-Pb concentration analyses of the olivine-phyric shergottite Tissint because U-Th-Pb isotope systematics have been intensively used as a powerful radiogenic tracer to characterize old crust/sediment components in mantle- derived, terrestrial oceanic island basalts. The U-Th-Pb analyses are applied to sequential acid leaching fractions obtained from Tissint whole-rock powder in order to search for Pb isotopic source components in Tissint magma. Here we report preliminary results of the U-Th-Pb analyses of acid leachates and a residue, and propose the possibility that Tissint would have experienced minor assimilation of old martian crust.

Moriwaki, R.↗

NASA NTRSDate not supplied

Additive Manufacturing (AM) for Propulsion Component and System Applications

NASA MSFC is developing several areas of additive manufacturing (AM) for propulsion component and system applications. These developments include new AM process and material development, large-scale AM pathfinder component fabrication and hot-fire testing, AM-centric design methodology, modeling and simulation, post-processing advancements, and new design applications of AM in aerospace. Some specific areas NASA has focused is the development and commercial infusion of AM supply chain for materials such as copper-alloy GRCop (Cu-Cr-Nb), Hydrogen-resistant alloys (NASA HR-1, JBK-75), refractory-based alloys (C-103, W, Mo, new formulations), and bimetallic and multi-metallic AM processes. Additional efforts have been focused on large scale AM demonstrating complex thin-wall structures up to 60” diameter using directed energy deposition. Material characterization, properties and component hot-fire testing has been completed using many of these newly developed AM alloys/processes. NASA has also focused on improvements to post-processing including powder removal, surface enhancements, and support removal to further realize cost and schedule benefits to the overall supply chain. These developments are part of the NASA Rapid Analysis and Manufacturing Propulsion Technology (RAMPT), Low Cost Upper Stage Propulsion (LCUSP) and Long Life Additive Manufacturing (LLAMA) projects, in addition to internal IRAD, and external collaborations.

Additive Manufacturing↗

NASA NTRS1988

Deposition and characterization of ZnS/Si heterojunctions produced by vacuum evaporation

Isotype heterojunctions of ZnS (lattice constant 5.41 A) were grown on silicon (lattice constant 5.43 A) p-n junctions to form a minority-carrier mirror. The deposition process was vacuum evaporation from a ZnS powder source onto a heated (450 C) substrate. Both planar (100) and textured (111) surfaces were used. A reduction of the minority-carrier recombination at the surface was seen from increased short-wavelength quantum response and increased illuminated open-circuit voltage. The minority-carrier diffusion length was not degraded by the process.

Landis, Geoffrey A.↗

NASA NTRS1991

Development, preparation, and characterization of high-performance superconducting materials for space applications

The preparation of high-temperature superconducting ceramics in bulk form is a major challenge in materials science. The current status of both partial melting and melt quenching techniques, with or without an intermediate powder processing stage, is described in detail, and the problems associated with each of the methods are discussed. Results of studies performed on melt-processed materials are reported and discussed. The discussion places emphasis on magnetization and on other physical properties associated with it, such as critical current density, levitation force, and flux creep. The nature of structural features which give rise to flux pinning, including both small and large defects, is discussed with reference to theoretical considerations. The rates of flux creep and the factors involved in attempting to retard the decay of the magnetization are surveyed.

Thorpe, Arthur N.↗

NASA NTRSDate not supplied

Optimization of Rocket Engine Components using Multi-Metallic Additive Manufacturing

Additive manufacturing (AM) is advancing many applications of component design for liquid rocket engines. AM has been demonstrated in various rocket component applications using a variety of monolithic metal alloys, many of which are traditional alloys for extreme environments. NASA and industry partners have focused in recent years to advance processing to create bimetallic and multicomponent AM processes and materials. The role of multi-metallic AM offers advantages since it can further optimize weight, optimize reliability and performance by increasing the strength to weight ratio of a component, and can optimize materials for various engineering requirements. NASA’s Rapid Analysis and Manufacturing Propulsion Technology (RAMPT) project has designed and manufactured a series of additively manufactured (AM) coupled combustion chambers, nozzles, and other engine components to advance new AM processes and materials with the goal of reducing cost and schedule for engine manufacturing. These designs incorporated multimetallic AM, which further enabled carbon-fiber composite overwrap to reduce overall thrust chamber assembly (TCA) mass. Various AM processes were demonstrated on these components using a copper-based alloy/superalloy bimetallic solution. The AM processes being explored individually and in combination for bimetallic applications include Laser Powder Bed Fusion (L-PBF), Laser Powder Directed Energy Deposition (LP-DED), and cold spray. The combination of bimetallic material combinations explored in this research include GRCop-based alloys and superalloys, Inconel 625 or NASA HR-1. One unique development that will be presented is the combustion chamber and nozzle as a single component by using freeform integrated DED to build the nozzle directly onto the aft end of the chamber. The various aspects of the additive manufacturing processes and challenges, materials characterization and mechanical testing, and hot-fire testing of bimetallic components in a relevant rocket engine environment will be discussed.

Additive Manufacturing↗

NASA NTRSDate not supplied

Component Applications using Metal Additive Manufacturing Techniques and Materials for Rocket Propulsion

The NASA Marshall Space Flight Center (MSFC) has been involved with various forms of metallic additive manufacturing for use in liquid rocket engine component design, development, and testing since 2010. These AM techniques have been demonstrated to significantly reduce hardware cost, shorten fabrication schedules, increase reliability by reducing the number of joints, and improve hardware performance by allowing fabrication of designs not feasible by conventional means. The focus at the NASA MSFC for these metal additive manufacturing techniques include laser powder-bed fusion (L-PBF), blown powder directed energy deposition (DED) and arc-based deposition. A variety of components have been evaluated and tested including thrust chamber injectors, injector components such as faceplates, regeneratively-cooled combustion chambers, regeneratively-cooled nozzles, gas generator and preburner hardware, and augmented spark igniters. To support these component applications in harsh environments, NASA has advanced a variety of “standard” additive manufacturing alloys such as those in the superalloy-family and also evolved new alloys including GRCop-84, GRCop-42, NASA HR-1, and JBK-75. The purpose of this presentation is to discuss the various programs at the NASA MSFC using AM to develop, fabricate, and test combustion devices hardware and the evolution of the new additive alloys. Additional information will be provided on the development of multi-metallic additive manufacturing, post-processing of AM techniques including surface enhancements (polishing) techniques, material and process characterization, future development programs, and dissemination of data to industry partners.

Additive Manufacturing↗

NASA NTRS1985

Improved silicon nitride for advanced heat engines

The AiResearch Casting Company baseline silicon nitride (92 percent GTE SN-502 Si sub 3 N sub 4 plus 6 percent Y sub 2 O sub 3 plus 2 percent Al sub 2 O sub 3) was characterized with methods that included chemical analysis, oxygen content determination, electrophoresis, particle size distribution analysis, surface area determination, and analysis of the degree of agglomeration and maximum particle size of elutriated powder. Test bars were injection molded and processed through sintering at 0.68 MPa (100 psi) of nitrogen. The as-sintered test bars were evaluated by X-ray phase analysis, room and elevated temperature modulus of rupture strength, Weibull modulus, stress rupture, strength after oxidation, fracture origins, microstructure, and density from quantities of samples sufficiently large to generate statistically valid results. A series of small test matrices were conducted to study the effects and interactions of processing parameters which included raw materials, binder systems, binder removal cycles, injection molding temperatures, particle size distribution, sintering additives, and sintering cycle parameters.

Yeh, H. C.↗

NASA NTRS1990

Application of carbon-powder-polymer composite as a continuous crack-length sensor

This paper explores the application of carbon-powder-impregnated polymeric composites for measuring crack extensions. The strain sensitivity of the gage material is shown to be very small. In the first series of tests, the gage material is characterized by measuring the change in electrical resistance due to machined slits for various gage lengths. The measured responses is compared with the response predicted from a very simple electrical model. On the basis of good correlation and repeatability, the usefulness of such gages to measure crack extensions is assessed by a second series of tests. Further work to improve the gage response by optimizing the shape of the gage and making the gage and the adhesive layer thinner is proposed. The presented concept, with improvements, can result in a reliable, inexpensive crack gage requiring inexpensive instrumentation.

Prabhakaran, R.↗

NASA NTRS1992

Toughening of PMR composites by gradient semi-interpenetrating networks

The toughening of the PMR-15 and LARC RP-46 high temperature thermosetting polyimides is presently attempted through the construction of a semiinterpenetrating network at ply interfaces through the use of the Matrimid 5218 thermoplastic polyimide powder, whose 315-320 glass transition temperature is compatible with the PMR matrices. The 60 vol pct fiber composites thus prepared for the two resins, with and without toughening, were comprehensively characterized in flexure, tension, intralaminar and short beam shear, compression and quasi-isotropic short-block compression, as well as modes I and II interlaminar fracture toughness and compression after impact.

Johnston, N. J.↗

NASA NTRSDate not supplied

Advancement of Novel Additively Manufactured Alloys for Space Applications

NASA has been involved in the development and maturation of metal additive manufacturing (AM) for space applications since the late 2000’s. Several efforts have focused on the understanding of AM processes through material characterization and testing, standards development, component fabrication, and infusion into development and flight applications. While many common aerospace alloys have been and continue to be a focus of ongoing development, the need for custom-alloy developments for high performance applications enabled by AM processes has been realized. The applications being targeted are liquid rocket engines with high heat fluxes, high pressure, and that utilize propellants such as hydrogen, which can degrade the alloy. NASA has recently focused on the development and advancement of novel alloy advancement using AM for use in these harsh environments, such as GRCop-42, GRCop-84, NASA HR-1, and JBK-75. These alloys have been evaluated using the laser powder bed fusion (L-PBF) and laser powder directed energy deposition (LP-DED) processes. The results from these processes have demonstrated that AM can enable rapid development of new alloy systems that can yield higher performances. These alloys have undergone the fundamental metallurgical evaluations, heat treatment study, and microstructure characterization and mechanical testing campaign. This, combined with direct application-specific component fabrication and hot-fire testing, enabled the increase of the Technology Readiness Level (TRL). This presentation will provide a background and overview of these AM-enabled novel alloys, AM processing development including metallurgical and mechanical property studies. It will also cover the latest advancement in the parallel component development and testing and future developments. The goal of these alloy development is to allow for technology infusion into NASA and commercial spaceflight missions as well as to establish and sustain the needed commercial AM supply chain.

Additive Manufacturing↗

NASA NTRS2022

Metal Additive Manufacturing for Spaceflight

NASA has been involved in the development and maturation of metal additive manufacturing (AM) for space applications since the 2000’s. Several efforts have focused on the understanding of AM processes through material characterization and testing, standards development, component fabrication, hot-fire testing, and infusion into development and flight applications. This presentation will discuss some of the various AM processes, components, testing and development efforts for spaceflight applications at NASA used on launch vehicles and propulsion systems. - AM process comparisons and selection for spaceflight applications. - Novel alloy development, characterization, and maturation for extreme environments. - Infusion and maturation of AM components into development and flight applications.

Additive manufacturing↗

NASA NTRS2004

High Pressure X-Ray Diffraction Studies of Nanocrystalline Materials

Experimental evidence obtained for a variety of nanocrystalline materials suggest that the crystallographic structure of a very small size particle deviates from that in the bulk crystals. In this paper we show the effect of the surface of nanocrystals on their structure by the analysis of generation and distribution of macro- and micro-strains at high pressures and their dependence on the grain size in nanocrystalline powders of Sic. We studied the structure of Sic nanocrystals by in-situ high-pressure powder diffraction technique using synchrotron and neutron sources and hydrostatic or isostatic pressure conditions. The diffraction measurements were done in HASYLAB at DESY using a Diamond Anvil Cell (DAC) in the energy dispersive geometry in the diffraction vector range up to 3.5 - 4/A and under pressures up to 50 GPa at room temperature. In-situ high pressure neutron diffraction measurements were done at LANSCE in Los Alamos National Laboratory using the HIPD and HIPPO diffractometers with the Paris-Edinburgh and TAP-98 cells, respectively, in the diffraction vector range up to 26 Examination of the response of the material to external stresses requires nonstandard methodology of the materials characterization and description. Although every diffraction pattern contains a complete information on macro- and micro-strains, a high pressure experiment can reveal only those factors which contribute to the characteristic diffraction patterns of the crystalline phases present in the sample. The elastic properties of powders with the grain size from several nm to micrometers were examined using three methodologies: (l), the analysis of positions and widths of individual Bragg reflections (used for calculating macro- and micro-strains generated during densification) [I], (2). the analysis of the dependence of the experimental apparent lattice parameter, alp, on the diffraction vector Q [2], and (3), the atomic Pair Distribution Function (PDF) technique [3]. The results of our studies show, that Sic nanocrystals have the features of two phases, each with its distinct elastic properties. and under pressures up to 8 GPa.

Palosz, B.↗

NASA NTRS1982

A compliant, high failure strain, fibre-reinforced glass-matrix composite

A glass-matrix composite reinforced by discontinuous graphite fibers was produced by hot pressing glass-powder-impregnated two-dimensional arrays of in-plane randomly oriented graphite fibers held together by approximately 5-10% by weight of organic binder (generally polyester). The composite tensile behavior is characterized by a highly nonlinear stress-strain curve which differs markedly from that of either unreinforced glass or a similarly reinforced epoxy-matrix composite. By virtue of this nonlinearity, the composite is able to redistribute applied stresses to achieve a high load-carrying capacity. The fibrous microstructure and the low fiber-matrix bond provide a mechanism for achieving high fracture toughness and unusually high compliance. For a 96%-silica-matrix composite, the strength is retained to over 1000 C.

Prewo, K. M.↗

NASA NTRS1986

Improved silicon carbide for advanced heat engines

The development of silicon carbide materials of high strength was initiated and components of complex shape and high reliability were formed. The approach was to adapt a beta-SiC powder and binder system to the injection molding process and to develop procedures and process parameters capable of providing a sintered silicon carbide material with improved properties. The initial effort was to characterize the baseline precursor materials, develop mixing and injection molding procedures for fabricating test bars, and characterize the properties of the sintered materials. Parallel studies of various mixing, dewaxing, and sintering procedures were performed in order to distinguish process routes for improving material properties. A total of 276 modulus-of-rupture (MOR) bars of the baseline material was molded, and 122 bars were fully processed to a sinter density of approximately 95 percent. Fluid mixing techniques were developed which significantly reduced flaw size and improved the strength of the material. Initial MOR tests indicated that strength of the fluid-mixed material exceeds the baseline property by more than 33 percent. the baseline property by more than 33 percent.

Whalen, Thomas J.↗

NASA NTRSDate not supplied

Effect of Heat Treatments on the Tensile Properties of Additively Manufactured 15-5 Ph Stainless Steel

This study investigated the effect of post-manufacture heat treatments on the microstructure and mechanical properties of 15-5 PH stainless steel (SS) fabricated by laser powder-directed energy deposition (LP-DED). Various heat treatment procedures (CA-H900 and CA-H1150) were conducted to evaluate their effects on the tensile behavior of LP-DED 15-5 PH SS. Scanning electron microscopy was used to characterize the microstructural features and the fracture surfaces. Tensile tests were performed to evaluate the mechanical properties at cryogenic and room temperatures. Reduction in area of CA-H1150 treated specimens after tensile tests was significantly higher than CA-H900 ones, while the ultimate tensile and yield strengths of CA-H900 specimens were higher compared to the CA-H1150 ones. The mechanical behavior of the LP-DED 15-5 PH SS in various heat treatment conditions is discussed based on their microstructures and fracture surfaces.

Laser powder directed energy deposition (LP-DED)↗

NASA NTRS1977

Characterization of lunar mare basalt types. II - Spectral classification of fresh mare craters

Telescopic reflectance spectra (0.3-1.1 microns) of fresh craters are presented and classified according to the spectral features observed. These spectra are the closest lunar surface analog to laboratory spectra obtained for lunar rock powders. Mineral absorption features can be identified in these crater spectra and interpreted using returned lunar samples. Spectra of craters to 2.5 microns are required for specific mineralogical determinations from remote observation. If the currently available telescopic spectra are representative, classification of lunar telescopic spectra indicates that most (more than 80%) of the lunar surface is composed of a finite number of discrete and describable geochemical units.

Pieters, C.↗

NASA NTRS1984

NDE for heat engine ceramics

Radiographic, ultrasonic, and scanning laser acoustic microscopy (SLAM) techniques were used to characterize silicon nitride and silicon carbide MOR bars in various stages of fabrication. Conventional and microfocus x-ray techniques were found capable of detecting minute high density inclusions in as-received powders, green compacts, and fully densified specimens. Significant density gradients in sintered bars were observed by radiography, ultrasonic velocity, and SLAM. Ultrasonic attenuation was found sensitive to microstructural variations due to grain and void morphology and distribution. SLAM was also capable of detecting voids, inclusions, and cracks in finished test bars. It was determined that thermoacoustic microscopy techniques have promise for application to green and densified ceramics.

Klima, S. J.↗

NASA NTRS1993

Ultrasonic inspection of a diffusion-bonded platelet rocket chamber liner

An ultrasonic inspection technique, which applies pulse-echo technology for examining the rocket chamber's liner-to-jacket interface was developed, which makes it possible to characterize disbonded layers in intimate contact. The method was used to inspect a simulated flat-geometry rocket chamber liner structure with debonded liner layers and to validate the use of boron nitride powder as a flaw introduction technique.

Matson, Douglas M.↗