NASA Glenn Research Center
Research & Technology
Materials Highlights - CY 2000
Processing Parameters for Blackglas TM CMC
Feasibility of IN-718 alloy
Relative Reactivities of Diamines
Single Crystal Oxide Material
Meeting on Diamond-like Coatings Research
Glenn Research Center's Distinguished Paper of the Year
National Space and Missile Materials Symposium
Materials Division / Industry Research Partnership
Dr. Nathan Jacobson
Next Generation Nickel-Base Superalloys for Turbine Airfoils
NASA UEET Ceramic Matrix Composites
Successful Hot Fire Testing of GRCop-84 (Cu-8 Cr-4 Nb)
Micromechanical and Dielectric Property Measurement Capability
Composite Cryogen Ducts and Feedlines
NASA GRC Team Contributes to Success of 2400°F CMC
Optimizing protective aluminum oxide adhesion in nickel-based single crystal
superalloys
Mechanistic Model for Intermediate Temperature Stress-Rupture of Ceramic
Matrix Composites (CMC)
The effects of prolonged high temperature exposure on the durability and
mechanical performance of polymer matrix composites
The value of Aero-Space materials technology synergism
Materials durability assessment for the Delta IV Evolved Expendable Launch
Vehicle
Mechanical testing of thin gage (1 mm) Titanium Aluminide (TiAl) alloys
Ceramic Matrix Composite (CMC) Rocket Engine Components
Phase-Change Enhancement of Carbon-Carbon Brakes
2000 R&D 100 Award
NASA Exceptional Acheivement Medal
Thesis defense
Gordon Research Conference on High Temperature Materials, Processes and Diagnostics 2000
Transverse tensile modulus of IM7 carbon fibers
Ceramic Matrix Composite (CMC) Tests Successful
GRCop-84 Alloy Development
Successful Casting of Inconel-718 Lattice Blocks
Preliminary Plan Outlined for Ultra High Temperature Ceramics Collaboration
with ARC
Williams International recognized Materials Division research staff
Dual Alloy Titanium Impeller Development
Interface Working Group
High-pressure sampling mass spectrometer
ASME Fellow, Center for High Performance Polymers and Composites
CMC Progress, Certificate of Recognition and Appreciation
Collaborative Research Projects for Aerospace Propulsion
Virtual Surgery
Resin Transfer Molding
January 2000
Processing Parameters for Blackglas TM CMC
GRC, in partnership with Allison, Northrop Grumman and the Air Force,
contributed to the development of processing parameters for a Blackglas
TM CMC tailcone that has been successfully engine tested on an Allison 2100.
The materials also is of interest as an exhaust tailcone on the Allison
3007 and for the Global Hawk Tier II aircraft. (Point of contact: 5130/Frances
Hurwitz, and 5160/Mary Ann Meador)
February 2000
Feasibility of IN-718 Alloy
Materials research efforts have provided answers to key questions regarding the feasibility of IN-718 alloy proposed for the heater head of a Stirling Converter, used as a power source on deep space satellite missions. The issues of Chromium loss in the vacuum of space and creep strength for the 100,000-hour design life were addressed both analytically and experimentally, and are confirming the viability of the material selection. Based on the results of additional studies on phase stability and precipitation kinetics, recommendations for a modification to the alloy heat treatment were made to Stirling Technology Corporation. They have adopted these recommendations, which will result in improved creep properties. This work is in support of the Stirling Converter program run by the Power & On-Board Propulsion Division. POC: 5120/Advanced Metallics Branch - Randy Bowman (433-3205)
Relative Reactivity of Diamines
A study is currently underway to develop a fast and efficient way to determine the relative reactivities of diamines used in the production of high temperature polyimide polymers. A difference in diamine reactivity will affect the processing conditions required by the polymer. Many diamines have been used in an attempt to tailor the properties of the resulting polymer but little is known about their reactivity towards polymerization. A series of important diamines have been examined by 15N Nuclear Magnetic Resonance (NMR) spectroscopy and some differences in their chemical shifts noted. Research is continuing to measure reaction rates to allow a correlation between the observed rates and the NMR data, with the goal of developing a quick screening process to estimate diamine reactivity. This work supports the development of new high temperature polymer matrix composites and is being done under the Hot PC project of the Aerospace Propulsion and Power Program. (Point of contact: 5150/ J. Chris Johnston)
Single Crystal Oxide Material
Extensive studies to identify the best single crystal oxide material for development as a refractive secondary solar concentrator for ultra-high temperature solar thermal engines have recently been completed. Fundamental oxide properties including thermal conductivity, fracture-creep strength, fracture toughness, and thermal shock behavior of the candidate oxides were investigated at high temperatures (up to 1400°C), as a function of the crystal orientations. Studies of rhenium interactions with the oxides and residual oxygen in the ambient, indicated that rhenium forms stable volatile oxides, even at low levels (parts-per-million) of oxygen. Thermo-mechanical stability was evaluated under the simulated solar engine transient and steady-state heat flux condition. The research enabled the selection of single crystal sapphire as the refractive solar concentrator and extractor material of choice, due to it's oxide stability and superior thermal shock resistance. A complete sapphire solar concentrator-extractor system has been fabricated for the final component testing in the Power and On-board Propulsion Technology Division. This work is in support of the Advanced Space Transportation Program. (Contact: Dongming Zhu, Nathan Jacobson (5160), Robert Macosko (5490)
Meeting on Diamond-like Coatings Research
Nine project management and research scientists from Japan met with the Environmental Durability (5160), Tribology and Surface Science (5140) and the Electro-Physics (5480) Branches on Friday, February 11, 2000, to discuss diamond-like coatings (DLC) research. Dr. Yoshinori Koga of the Japan Fine Ceramic Center, Frontier Carbon Core Laboratory of the National Institute of Materials and Chemical Research, served as lead for the technical group. Six presentations were provided by the visitors, which included descriptions of their organizations' advanced coating deposition facilities and overviews of some of the fundamental project work they have underway in DLC, cubic-boron nitride, and carbon nanotubes. Technical overviews, of applicable research areas (i.e. advanced materials, including coatings) were presented by the Branch Chiefs of 5160, 5140, 5480 and 5130 (Ceramics). Tours and fundamental research discussions were held at selected facilities. This meeting was conducted in support of the Materials Division discipline interests. Contact: Leslie Greenbauer-Seng(3-6781) and Dr. Kazuhisa Miyoshi (3-6078)
Glenn Research Center's Distinguished Paper of the Year
The paper entitled "Surface Segregation in Multicomponent Systems: Modeling of Surface Alloys and Alloy Surfaces," published in Computational Materials Science, 15(2), 1999, 165 and as NASA TM-1999-209042 has been selected as the Glenn Research Center's Distinguished Paper of the Year. The article defines the state-of-the-art in simulations of multicomponent systems and it deals with systems at a level of complexity that goes far beyond any other modeling technique in current use. The variety of topics covered constitute, due to their fundamental nature, the starting point for groundbreaking research in areas of surface science previously unexplored from a theoretical and computational standpoint. Co-authors on the paper are Guillermo Bozzolo (OAI), John Ferrante (NASA, retired), Ronald Noebe (5120), Brian Good (5410), Frank Honecy (5140) and Phillip Abel (5140). This work is in support of Hot PC, HITEMP & PPM programs. Point of Contact: Dr. Philip Abel, 3-5032.
March 2000
National Space and Missile Materials Symposium
GRC played a major role in organizing and carrying out the National Space and Missile Materials Symposium, February 27-March 2, 2000 in San Diego, CA. Involvement included arranging for partial financial support as noted below, Steering Committee membership, administrative support at the conference, and setting up and staffing a Materials and Structures exhibit of GRC capabilities and accomplishments. The Space Directorate, Space Transportation Projects Office, and the Propulsion and Power Technology Base R & T Program Office, and the Aeronautics Directorate, High Speed Research Office, provided partial financial support for the conference.
This work is in support of the Space Transportation Program. Point of contact: 5130 / James D. Kiser
Materials Division / Industry Research Partnership
A $6.5M (30% NASA/70% Industry cost share) five-year research partnership
with Rolls-Royce Allison, Howmet, Cannon-Muskegon, the Purdue Research Foundation
and the Materials Division, has been successfully completed. The objective
of the cooperative agreement was to increase the competitiveness of U.S.
manufactured small turboshaft engines by extending the life of current small
turbine wheels, while maintaining affordability. The research explored development
of advanced superalloy materials, evaluation of advanced casting techniques,
and wheel designs to produce integrally-bladed disks, possessing a mechanically
optimized grain morphology with elongated grains in the airfoil and fine
grains in the hub. An affordability study was performed indicating as much
as a 15% increase in customer value could be achieved. Engine tests demonstrated
a doubling of the component life using an optimized superalloy and established
the feasibility of even greater increases in component life with more advanced
materials developed within the project.
(Point of Contact: 5160/Dr. James Nesbitt, 3-3275)
Dr. Nathan Jacobson
Dr. Nathan Jacobson was nominated by the international research community to Chair the July 23-28, 2000, High Temperature Materials, Processes, and Diagnostics Program of the 21st Century Gordon Research Conference. The Administrator's Telecon notes (3/6/00) contained a report from Dr. Nicogossian to Mr. Goldin pointing out the use of a Microgravity-funded levitated alumina molten sample photo having been featured on February 11th cover of Science. Dr. Jacobson had selected this work/photo as his nomination for this prestigious recognition by Conference officials. In addition, each discipline conference chair submits a nominee for recognition as the greater Conference's most honored lecturer. Dr. Jacobson's nominee, Dr. Alexandra Navrotsky, from the University of California at Davis, was selected as this year's Keynote Lecturer. (Point of Contact: 5160/Dr. Nathan Jacobson, 3-5498)
Next Generation Nickel-Base Superalloys for Turbine Airfoils
Nickel base superalloy single crystals represent the state of the art for the materials used as turbine airfoils in today's and future aerospace propulsion systems. The HSR-EPM Airfoil Alloy Development Team comprised of NASA GRC, GE Aircraft Engines, and Pratt & Whitney recently defined the full specification ranges for the composition of the next generation turbine airfoil alloy. Key steps in the development of this alloy were to employ a combination of precise compositional control with appropriate processing to produce excellent high temperature creep strength with good microstructural stability. Significance: Although this alloy was developed for the High Speed Civil Transport mission, it also has applications for advanced subsonic and military engines. For example, it has been identified for numerous components to meet the goals of several IHPTET technology demonstrators. Work is continuing in the Ultra Efficient Engine Technology Program to further develop the alloy and processing methods for improved compatibility with the thermal barrier coating system. Points of Contact: 5100/Dr. Rebecca MacKay, 433-9516; 5120/Frank Ritzert and Dr. Anita Garg
April 2000
NASA UEET Ceramic Matrix Composites (CMC) Development Team Contributes to Success of Air Force 2400 F CMC Program
Under an Air Force contract aimed at demonstrating that an advanced SiC/SiC composite that can operate at 2400oF in engine hot sections, Honeywell Advanced Composites has been collaborating closely with the UEET CMC Development Team to identify improved materials and processes along with process and property guidelines. Because of prior expertise gained under the EPM program, the NASA team was given sole responsibility for fabric qualification testing as well as for fiber selection and fiber pre-treatment using a NASA-developed process. Composite fabrication and testing at Honeywell as well as process and property models from NASA have recently confirmed that Air Force program goals can indeed be achieved using the NASA fiber process. This is significant because NASA approaches for 2400 F SiC/SiC composites will be implemented by the Air Force in IHPTET and related programs. This work is in support of the Ultra Efficient Engine Technology Program. Point of Contact: 5130 / James A. DiCarlo / 3-5514
Successful Hot Fire Testing of GRCop-84 (Cu-8 Cr-4 Nb)
In a cooperative program with MSFC, the advanced copper alloy GRCop-84 was successfully tested under realistic rocket engine conditions. The current program represents a combination of the advanced alloy developed by GRC and an advanced manufacturing technique developed by MSFC to produce spool pieces, which are representative of combustion chamber liners in regeneratively cooled rocket engines. Two spool pieces were produced at MSFC by the Vacuum Plasma Spray (VPS) method, which is being developed because of its potential for cost reduction. The first piece had no coating on the interior surface while the second had a functional gradient NiCrAlY coating. The NiCrAlY coating was added to stop blanching, a form of environmental degradation unique to rocket engines, and to act as a thermal barrier. The spool pieces used a robust design previously developed at GRC, and testing was conducted in GRC's Cell 22. Approximately 500 seconds total of hot fire testing was conducted on the two spool pieces, at oxygen/fuel ratios up to 7.0, the equivalent of a 6,000°F flame. Both spool pieces showed no signs of degradation. Most importantly, there were no indications that the coating was debonding from the substrate, even after 17 cycles lasting up to 30 seconds each. Future plans include exploring the durability limits of both coated and uncoated designs through additional hot fire tests. Significance: The testing demonstrated that VPS is a viable method for producing combustion chamber liners. It also demonstrated that functional gradient coatings that are an integral part of the combustion chamber liner can withstand rocket engine conditions. This work was funded by MSFC, with supporting technologies funded by GRC's Hybrid Hyperspeed Propulsion and RLV-focused projects. POC: David L. Ellis, 5120/Advanced Metallics Branch, Materials Division (216) 433-8736
May 2000
Title: Micromechanical and Dielectric Property Measurement Capability
Aluminum nitride has been shown to have great potential as a high temperature electronic packaging material for advanced high component density electronic devices as well as piezoelectric capabilities. In house capabilities to nondestructively characterize mechanical damping and elastic modulus have been expanded to include electrical properties. Results at temperature up to 1000oC indicate intrinsic damping in aluminum nitride is too weak to suppress mechanical vibrations. This technique can be used to non-destructively determine impurity levels in electronic substrate materials. The system can also be used to detect component damage. Measurements can be performed as a function of frequency, temperature, and environment. The new capability will be applied to support MEMS and oxide fuel cell materials research. This work is in support of the Propulsion and Power Research and Technology Program. Point of Contact: 5130 / Jon Goldsby
Composite Cryogen Ducts and Feedlines
As part of an effort under the Reusable Launch Vehicle Focused Technology Program to develop polymer matrix composite cryogen ducts and feedlines, Fiber Innovations has completed the processing of six LH2 feedline subcomponents. These subcomponents, one of which is picture below, are 8" in inside diameter, each arm of the elbow is 12" long with a 16" bend (radius). This effort demonstrates the use of low cost manufacturing (Resin Transfer Molding) to reduce component costs and toughened epoxies to improve duct durability at cryogenic temperatures. Use of lightweight composite ducts and feedlines could lead to as much as a 30% reduction in component weight. These subcompents have been shipped to MSFC for cyrogenic testing. As a follow on to this activity, Fiber Innovations will prepare two more of these test articles from a GRC developed high temperature polymer.
NASA GRC Team Contributes to Success of 2400 F CMC
Point of contact: 5130 / James A. DiCarlo / x5514
The GRC CMC Development Team has been providing key innovations in fiber pretreatment to enable Honeywell Advanced Composites to develop an advanced SiC/SiC composite that can operate at 2400 F in engine hot sections. Honeywell is funded by an Air Force contract.
The experience gained in this collaboration will facilitate the attainment of UEET goals for a durable CMC operating at 2700 F surface temperature and 2400 F material temperature for combustor liner and vane applications. NASA approaches for 2400 F SiC/SiC composite may also be implemented by the Air Force in IHPTET and related programs. The collaboration provides the cornerstone for a joint NASA /DOD / DOE joint CMC material development roadmap. This work is in support of the Ultra Efficient Engine Technology Program.
Optimizing protective aluminum oxide adhesion in nickel-based single crystal superalloys
Optimizing protective aluminum oxide adhesion in nickel-based single crystal superalloys to enhance their high temperature structural material performance/life has been an important role for the Materials Division. Industry's current practice is to make small additions of reactive elements, such as 0.1%Y, Zr, and Hf, to the superalloy to improve adhesion and oxidation resistance. GRC provided the experimental evidence confirming the hypothesis that sulfur segregates to the oxide-metal interface, inducing scale spallation. The reactive element getters the sulfur, minimizing the segregation, therefore, extending oxidative resistance of the superalloy at operational temperatures. However, since reactive elements do cause casting process mold reactions, reduced yields, and inhomogeneities in the superalloy, new approaches have been explored, hydrogen annealing at GRC and melt desulfurization by some material suppliers. GRC's has conducted extensive studies, to understand the cyclic oxidation mechanisms at work, to optimize and quantified the materials durability, and to assess the trade-offs (relative cost and complexity) of removing the sulfur rather than relying on the reactive element addition effect. Minimum sulfur levels, identification of reactive element concentrations as a function of sulfur concentrations, optimization of the hydrogen annealing process, and comparative effectiveness of melt desulfurization, have been completed for the most advanced single crystal superalloys of interest to the engine companies. This work has been supported by the HiTEMP, FQE and HOTPC Project Offices. (Contact: 5160/Dr. James L. Smialek, 3-5500)
June 2000
Mechanistic Model for Intermediate Temperature Stress-Rupture of Ceramic Matrix Composites (CMC)
A model was developed to predict the time to failure of woven SiC/SiC (silicon carbide fibers/silicon carbide matrix composites subjected to stress-rupture in air at 8150C. The model is based on the physical mechanisms that lead to failure for composites with through thickness matrix cracks. For this case, predictions were in excellent agreement with experimental data. For less than fully cracked matrix conditions the model underestimated life. The current work is aimed at applying this model to stress-relaxation conditions, and expanding the model for microcrack growth to make the model more useful at regions of high stress-concentration such as notches and holes. This research is in support of Higher Operating Temperature Propulsion Components Project. The significance is that a key component of the comprehensive life prediction model that is enabling for CMC application in engines is maturing. (Point of Contact: 5130/Greg Morscher/3-5512)
The effects of prolonged high temperature exposure on the durability and mechanical performance of polymer matrix composites
Understanding the effects of prolonged high temperature exposure on the durability and mechanical performance of polymer matrix composites is essential to development of reliable and safe aero-space components. Recent research within the Polymers Branch has focused on identifying the effects of long-term aging at elevated temperatures on the compression properties of advanced composites. Relationships between degradation mechanisms and changes in compression properties have been identified that will enable the development of models that can reliably predict the long-term durability of composites under these simulated use conditions. This research was initiated under the Advanced Subsonic Technology Program and is being continued under the High Operating Temperature Propulsion Components program. Results from this work can be applied to the development of safe and reliable aircraft engine components (HOTPC, and UEET) as well as propulsion and airframe components for Reusable Launch Vehicles. Point of Contact: 5150/ Dr. Kenneth J. Bowles, 216 433-3197, Kenneth.J.Bowles@grc.nasa.gov
The value of Aero-Space materials technology synergism
The value of Aero-Space materials technology synergism is apparent in space transportation studies underway in ceramic materials. Research, funded by the Enabling Propulsion Materials in the High Speed Research Program, led to the discovery and quantification of severe recession of Silicon Carbide (SiC)-reinforced SiC combustor liner materials when exposed to the High Speed Civil Transport combustion environment. A predictive capability was successfully developed based upon extensive studies. This research has provided the foundation for estimating recession rates of silica-based material systems in space propulsion environments. A study has recently been conducted, in support of the Boeing-Rocketdyne Delta IV Evolved Expendable Launch Vehicle (EELV). Recession rates of silica were calculated for seven cases representative of nozzle conditions. Recession rates were shown to have a very strong dependence on material temperature. For constant nominal gas chemistries, constant pressure, and constant gas velocity, recession rates varied by four-orders-of-magnitude for a material at 3150°K and at 1700°K. Predictive recession studies have also been performed for carbon-reinforced SiC materials targeted for nozzle ramp, gas generator, and turbopump blisk applications in the Aerospike propulsion system. Although additional research is required to verify the predictive capability for space applications, an excellent tool is already in use to aid in assessing and screening material systems of interest. (Contact: 5160/Dr. Elizabeth J. Opila, 3-8904)
Materials durability assessment for the Delta IV Evolved Expendable Launch Vehicle
An in-house study has been completed in support of a materials durability assessment for the Delta IV Evolved Expendable Launch Vehicle (EELV) project involving Boeing-Rocketdyne. Recession rates of silica, calculated for seven cases representative of nozzle conditions, were shown to have a very strong dependence on material temperature. For constant nominal gas chemistries, constant pressure, and constant gas velocity, recession rates varied by four orders-of-magnitude for a material at 1440oC and at 2890oC. Predictive recession studies have also been performed for carbon-reinforced silicon carbide (SiC) materials targeted for nozzle ramp, gas generator, and turbopump blisk applications for the Aerospike propulsion system. The Enabling Propulsion Materials (High Speed Research Program) funded materials research which uncovered and quantified severe recession in SiC-reinforced SiC combustor liner materials when exposed to high water vapor levels typical of combustion environments. A predictive capability was developed based upon extensive studies, and has now provided the foundation for estimating recession rates of silica-based material systems in space propulsion environments. Applying a predictive tool, developed for an aeronautics mission, to a space application need, demonstrates the potential for aero-space synergy in materials research. (Contact: 5160/Dr. Elizabeth J. Opila, 3-8904)
July 2000
Mechanical testing of thin gage (1 mm) Titanium Aluminide (TiAl) alloys
Mechanical testing of thin gage (1 mm) Titanium Aluminide (TiAl) alloys is currently being undertaken to evaluate its behavior in comparison to other advanced TiAl-based alloys. Since this sheet was produced by direct rolling of as-cast ingots, it represents a cost saving of 35 % over those alloys that require forging prior to rolling. To date tensile, fatigue and creep rupture testing has been conducted between room temperature and 815 ºC on longitudinal and transverse specimens taken from three individual sheets. Results indicate that all the mechanical properties are reproducible and independent of specimen orientation. In general, the mechanical properties of the sheet product are comparable to those measured on cast versions, and minor differences in the properties can be directly attributed to the grain sizes in both forms. The combination of lower sheet processing cost with reproducible and acceptable mechanical strengths makes this alloy attractive for aerospace applications. This work is funded by the UEET Lightweight Structures Task. Point of Contact: J. D. Whittenberger, 5120/Advanced Metallics Branch, 3-3196.
Ceramic Matrix Composite (CMC) Rocket Engine Components
Andrew Eckel, Martha Jaskowiak, Doug Kiser, and Jerry Lang of NASA Glenn teamed with Michael Effinger, R.G. Clinton, Jr., Jay Dennis, Sandy Elam, and Gary Genge of the NASA Marshall to prepare the paper "Fabrication & Testing of Ceramic Matrix Composite Rocket Propulsion Components" that was given by M. Effinger at the AeroMat 2000 Conference, June 2000. The topic was NASA's pursuit of ceramic matrix composite (CMC) rocket engine components to enable the achievement of the aggressive 2nd and 3rd Generation Space Transportation safety and cost goals. This paper exemplifies the strong cooperation and teamwork between GRC and MSFC in ceramics for space transportation. This work is in support of the Advanced Space Transportation Program.Point of Contact: 5130 / Doug Kiser / 3-3247
Phase-Change Enhancement of Carbon-Carbon Brakes
The Materials Division has been a key technical contributor to the successful Air Force funded technology demonstration effort, "Phase-Change Enhancement of Carbon-Carbon Brakes" through a NASA Reimbursable Space Act Agreement with OAI; also in participation with Advanced Braking Systems Corporation and Applied Sciences, Inc. (An Air Force press release is anticipated in late July or early August 2000). Computational thermodynamic modeling and high temperature compatibility behavior research studies of phase-change materials, conducted at NASA Glenn, provided the technical data for brake system energy storage material selection. The project is currently in the second year of a three-year effort. The enhanced carbon-carbon brakes are currently demonstrating a 20% improvement in energy capacity as the phase change material converts from a solid to a liquid. The technology will enable cooler brake rotors, stators and surrounding wheel assembly components. This work was sponsored by the Aero-Space Propulsion Program, Hot PC Project. (Contact: 5160/Dr. Elizabeth J. Opila, 3-8904)
2000 R&D 100 Award
Dr. William Alston (US Army Research Lab/GRC), Dr. Gloria Sivko (former Summer Faculty Fellow) and Mr. Daniel Scheimann (Dynacs) were notified by Research and Development Magazine that their invention, "PMR Polyimide Extended Shelf Life Technology", has been selected for a 2000 R&D 100 Award. Point of Contact: 5150/Dr. William Alston, 3-3220.
NASA Exceptional Acheivement Medal
Dr. Chun Hua (Kathy) Chuang was the recipient of a NASA Exceptional Acheivement Medal at the recent GRC Awards Ceremony. This award recognizes her contributions and achievements in the development of processable, durable high temperature polymers for aeropropulsion and space transportation applications.
Thesis defense
Christopher Gariepy, a NASA GSRP Fellow in the Department of Polymer Science at the University of Akron, successfully defended his PhD thesis entitled "Synthesis, Characterization and Physical Properties of Processable PMR-Type Polyimides". Dr. Gariepy performed all of his thesis research at GRC in the Polymers Branch. New high temperature polymers that he developed in this research are currently being evaluated at GRC for use as RTM processable resins for Space Transportation (RLV cryotank) applications. Point of Contact: 5150/Michael A. Meador, 3-9518
Gordon Research Conference on High Temperature Materials, Processes and Diagnostics 2000
Dr. Nathan Jacobson is the chairman and organizer of the prestigious Gordon Research Conference on High Temperature Materials, Processes and Diagnostics 2000. The conference under way this week, at Plymouth State College in Plymouth, New Hampshire, is proving to be a tremendous success. It has required two years of careful planning and numerous hours to define the content of the conference, identify technical speakers and coordinate conference materials for several very large mailings to the top scientists and engineers from throughout the world. Over 110 attendees are at the conference. The technical program includes presentations on the thermodynamics and high temperature behavior of advanced materials as well as addressing the technical challenges faced in their application in high temperature devices, fuel cells and space experiments.
In addition, 48 poster presentations are a part of the conference technical program. GRC is a sponsor of the Gordon Conference and Environmental Durability Branch staff are participating as the conference chair, technical poster (3) authors, and as discussion leaders (2). The research depicted in the NASA posters was supported under the Aero-Space Propulsion Base, including Supersonic Propulsion and HOTPC, as well as the Director's Strategic Research Fund. (Point of Contact: 5160/Dr. Nathan Jacobson, 3-5498.
August 2000
Transverse tensile modulus of IM7 carbon fibers
Research performed at GRC and Ohio State University has demonstrated that the transverse tensile modulus of IM7 carbon fibers is strain rate dependent. Although strain rate dependence has been observed for glass fibers, the properties of carbon fibers are generally considered to be independent of strain rate. Test specimens of epoxy resin and carbon/epoxy composite were designed and fabricated at GRC. A unique feature of this specimen design is that the same design can be used for either quasi-static tensile tests or high strain rate tensile tests. An additional benefit is that the gage section is sufficiently large to allow the use of a strain gage for accurate strain measurement during a high strain rate Hopkinson bar test. Tests performed at Ohio State University indicated that stiffness and strength were highly rate dependent for the resin and for all composite lay-ups containing off axis plies. Data was analyzed at GRC using a state variable constitutive model for the rate dependence of the resin and micromechanics theory for the overall response of the composite. This analysis demonstrated that the usual assumption that carbon fiber properties are not strain rate dependent is valid in the longitudinal direction but not in the transverse direction. Results of this work will be used to provide more realistic material models for use in finite element computer codes (ABAQUS, LS-DYNA) that are currently being used to develop impact resistant composite engine cases for the Ultrasafe Project, Aerospace Propulsion and Power Program.
(Points of Contact: 5150/Gary Roberts, 5920/Rob Goldberg, 5930/Mike Pereira)
Title: Ceramic Matrix Composite (CMC) Tests Successful
The Rockwell Science Center has been developing open woven structure architecture ceramic matrix composites for cooled nozzle ramp and other propulsion applications under an Air Force Research Laboratory contract under the Integrated High Payoff Rocket Propulsion Technology Program (IHPRPT). The GRC Ceramics Branch was part of the contract team with the primary task being to test the thermal performance of the panels under a variety of aero thermal conditions. Each panel was to subject to eight conditions where the chamber pressure and the mixture ratio of the H2/O2 thruster were the primary variables. Each test condition increased in severity, culminating with the maximum output of the thruster at a chamber pressure of 500psi and an oxidizer-to-fuel ratio of 7.0. Testing of the integrally woven tubular CMC panel structures at NASA GRC's Cell 22 went extremely well. Both the polymer-infiltration-pyrolysis and melt infiltration densified panels survived the maximum fury of the thruster without any visible damage. In addition, a very high level of customer satisfaction was achieved. This work is in support of the Advanced Space Transportation Program. Point of Contact: 5130/Andy Eckel, 3-8185
GRCop-84 Alloy Development
The GRCop-84 alloy (copper - 8 at% chromium - 4 at% niobium) has been under development at NASA GRC, as an advanced material for reusable launch vehicle (RLV) combustion chamber liner and nozzle ramp applications. The alloy possesses excellent mechanical and thermophysical properties that make it a strong candidate for applications where good high temperature strength, creep resistance and low cycle fatigue lives combined with high thermal conductivity are required. Currently NARloy-Z (copper - 3 wt.% silver - 0.5 wt.% zirconium) is the baseline alloy specified by RLV propulsion system designers. Establishing the improved performance of GRCop-8 relative to NARloy-Z is required to replace NARloy-Z as the baseline alloy. Extensive studies of the GRCop-84 resistance to oxidative degradation indicate that the alloy's oxidation resistance in oxygen at temperatures below approximately 700ºC is about ten times better than that of NARloy-Z. At higher temperatures its oxidation resistance is comparable to NARloy-Z. Continued studies to develop and optimize protective copper-chromium coatings for improved oxidation resistance of GrCop-84 and NARloy-Z are underway. This research is supported by the Aerospace Propulsion and Power Program (HOTPC and Hybrid Hyperspeed). Points of Contact: 5160/Dr. Linus Thomas-Ogbuji (3-6463) and 5120/Dr. David Ellis (3-8736)
September 2000
Successful Casting of Inconel-718 Lattice Blocks.
Standard structural materials can now be fabricated into lattice blocks, which are three dimensional structures consisting of interconnecting struts that are reminiscent of bridges, space frames or geodesic domes, only on a meso- or micro-scale. Lattice block materials have been shown to provide very high stiffness and strength with only a fraction of the weight of the parent alloy. Recently, a low cost casting method has been developed by JAM Corp, Boston MA for constructing engineering materials such as aluminum and stainless steels into lattice blocks. We have initiated a research program to extend this technology to high temperature alloys such as Ni-base superalloys. Inconel-718 was chosen to demonstrate feasibility. Initially there were numerous problems in making and assembling the wax patterns of our design. After a 6-month development program, a total of ten Inconel-718 lattice block castings (each 6"x 12" x 0.5" thick) have been produced and have passed preliminary inspection. Post-casting processing and evaluation of system-specific mechanical properties of these specimens are in progress. This work is in support of the Ultra Efficient Engine Technology (UEET) Lightweight Structures sub-project. Points of Contact: 5120/ M. G. Hebsur, (216) 433-3266, R. D. Noebe and J. D. Whittenberger.
Preliminary Plan Outlined for Ultra High Temperature Ceramics Collaboration with ARC
A meeting between some GRC personnel conducting research on ceramics (Ceramics Branch, Environmental Durability Branch, and Life Prediction Branch) and ARC personnel was held to discuss assessment, and development, if warranted, of Ultra High Temperature Ceramics for propulsion applications in the Ultra Efficient Engine Technology (UEET) program. This class of ceramics has been used for one-time reentry leading edge applications at temperatures above 4000 F. As a result of the meeting it was agreed that GRC personnel would conduct an assessment of key environmental durability and mechanical properties and jointly evaluate the results with ARC. Research paths were outlined for the two possible outcomes of this assessment: further development for propulsion applications if positive, and search for improvements if negative. This work is in support of the Ultra Efficient Engine Technology Program. Point of Contact: 5130/Stan Levine, 3-3276, 2100/Ajay Misra/3-8193.
Williams International Recognized Materials Division research staff
Williams International recognized Materials Division research staff, Dennis Fox, John Gayda and Michael Cuy, for their technical contributions toward the successful development of the Williams' FJX-2 jet engine, under the sponsorship of the General Aviation Propulsion Program. Division expertise in exploring and assessing the high temperature environmental durability of coatings, on turbine blades and vanes, fatigue and crack growth in titanium materials, for turbine disks and blades, and electron beam welding process characterization, were valuable to the selection and application of advanced materials for this engine. Point of Contact: 5160/Dennis Fox, 3-3295 and 5120/John Gayda, 3-3273.
Dual Alloy Titanium Impeller Development
Many smaller gas turbine engines utilize a combined axial-centrifugal compressor, which is often limited by the speed and operating temperature of the impeller. Current impellers, which are made from a single alloy, may not meet projected operating speeds and/or temperature requirements of future designs. To meet these challenges, NASA GRC Honeywell, and GEAE developed and tested a dual alloy titanium impeller with enhanced speed and temperature capability. The impeller employed a high-strength titanium alloy (Ti-6246) in the bore that was bonded to a high temperature, creep resistant titanium alloy (Ti-834) in the "airfoil" section. Utilizing AST funding, the impeller design, alloy selection, and bonding technology were developed. This was followed by fabrication and NDE of several full-scale impellers. Under UEET funding, one of the full-scale impellers was then subjected to spin testing at elevated temperature. The results of that testing showed the impeller could withstand speeds in excess of 130% of design requirements without any distress at the bond line. Point of Contact: 5120/John Gayda 3-3273.
October 2000
Interface Working Group
The Interface Working Group (IWG) is an informal consortium of the Air Force Research Laboratory (AFRL), NASA Glenn, and Oak Ridge National Laboratory and allied industrial and university partners. The group meets annually to discuss the challenges of composite interface development, share solutions to common problems and report on new developments. A steering committee with two representatives from each of the government labs plans and conducts the meetings on a rotating basis. The narrow focus of the IWG meeting provides a useful forum for detailed discussion of interface fabrication and development issues and an extended opportunity for informal technical discussions between government, industry and university representatives. The most recent meeting, September 26-29, 2000, was hosted by AFRL. The progress made in interface development for oxide-oxide composites with monazite interfaces and silicon carbide based composites with boron nitride interfaces was highlighted. This work is in support of the Ultra Efficient Engine Technology Program, and Higher Operating Temperature Propulsion Components. Point of Contact: 5130/ Serene Farmer, 3-3289
High-pressure sampling mass spectrometer
The high-pressure sampling mass spectrometer is a unique facility, one of only a few worldwide, used to conduct high temperature chemistry research in the Materials Division. The system has been used to monitor volatile products from solid-gas reactions both in materials interactions in simulated combustion environments, as well as studies to identify suitable phase change materials for use in advanced braking system concepts (Air Force Dual Use Program). The mass spectrometer's capabilities have been enhanced by the addition of a new Windows-based data acquisition system that can be readily used by different researchers using the instrument. The new data system, which replaces an antiquated chart recorder, allows researchers more control over sampling rates for improved signal-to-noise ratios. Multiple scans can be overlaid while data is being acquired so that the emergence or disappearance of peaks can be easily monitored in real time. Current and future studies using this instrument will greatly benefit from these system improvements. The work was funded by the Supersonic Propulsion Office. Contacts: 5160/Dr. Judith V. Auping (3-5016), Dr. Elizabeth J. Opila (3-8904) and Dr. Nathan S. Jacobson (3-5498). This work is in support of the Ultra Efficient Engine Technology Program, and Higher Operating Temperature Propulsion Components. Point of Contact: 5130/ Serene Farmer, 3-3289
ASME Fellow, Center for High Performance Polymers and Composites
Dr. Alan Freed has been elected a Fellow of the American Society of Mechanical Engineering. This award is in recognition for Dr. Freed's contributions to the field of engineering mechanics and for his service to ASME. Point of Contact: 5150/Alan D. Freed
Dr. Frances Hurwitz (5130) and Dr. Michael Meador (5150) attended the annual Technical Review Committee site review for the NASA Center for High Performance Polymers and Composites (HiPPAC) at Clark Atlanta University on October 18 and 19. The HiPPAC Center is one of seven Research Centers established by Code EU. GRC has responsibility for administering the HiPPAC Cooperative Agreement. A Technical Review Committee, comprised of representatives from GRC, LaRC, and MSFC, reviews the progress at the HiPPAC Center on an annual basis and makes recommendations to HiPPAC about technical directions for the upcoming year. One outcome of this year's review is a new start at HiPPAC in nanotechnology. As a part of this effort, a PhD student from Clark Atlanta will perform all of her thesis research at GRC as part of an effort to chemically functionalize carbon nanotubes. Point of Contact: 5150/Michael A. Meador
November 2000
CMC Progress Under UEET
The progress made during the first year of the Ultra Efficient Engine Technology Program in the area of 2700 F ceramic matrix composite (CMC) system development was reported informally to DOD and an industry group representing the aircraft engine companies and CMC material suppliers. Among the key CMC developments reported were the in situ formation of boron nitride fiber coatings, and fiber and tow spreading by mechanical agitation. In situ fiber coating formation by Sylramic silicon carbide fiber heat treatment improves the durability, temperature capability, and strength of the CMC. Fiber and tow spreading, also known as fluffing, by mechanical agitation improves the uniformity of the CMC microstructure by enabling better infiltration of the chemical vapor, slurry, and melt constituents used to densify the CMC. This imparts improved strength and stiffness. This work is in support of the Ultra Efficient Engine Technology Program. (Point of Contact: 5100/James A. DiCarlo).
Certificate of Recognition and Appreciation
Dr. Sai V. Raj of the Materials Division was presented a Certificate of Recognition and Appreciation by The Minerals, Metals & Materials Society for planning and organizing a symposium entitled "Rate Processes in Plastic Deformation II: Towards an Unified Theory of Deformation," held during The Metallurgical Society Fall Meeting in St. Louis, MO, October 8-12, 2000. Dr. Raj also presented a technical paper describing his experimental, microstructural and modeling research of creep mechanisms and creep substructures in advanced metallics. The UltraSafe Project funded this work. (Point of Contact: 5160/S. V. Raj).
Collaborative Research Projects for Aerospace Propulsion
The Materials Division has initiated two collaborative research projects for aerospace propulsion applications. Kick-off meetings were held October 17 and 25, 2000 with Allison Advanced Development Corporation/Rolls Royce America and Boeing Rocketdyne, respectively. Allison Advanced Development Corporation (AADC)/Rolls Royce America and a NASA GRC team from 5100/5900 will develop coatings to improve the erosion resistance of high temperature polymer composites for commercial and military advanced gas turbine engine applications. Boeing Rocketdyne and a NASA GRC team from 5100/5900 will investigate the use of lightweight graphite fiber polymer composites for reusable launch vehicle propulsion applications. Engine tests in both HOTPC projects are scheduled to test the durability of materials developed at NASA GRC. Point of Contact: Jim Sutter, 5150
December 2000
Virtual Surgery
Dr. Alan Freed (5150), Marvin Hirshberg, and Dr. Dale Hopkins (5930) visited Dr. Ivan Vesely at the Cleveland Clinic to tour his laboratories and discuss potential collaborations. Drs. Freed and Hopkins are co-Principal Investigators along with Dr. Vesley on a proposal to the DoD on the development of analytical models to permit surgeons to perform "virtual surgery" on patients using robots guided by surgeons. Dr. Freed is exploring the possibility of co-locating at the Clinic if the proposal is successful in gaining funding. Points of Contact: 5150/Dr. Alan Freed , 3-8747, 5920/Dr. Dale Hopkins 3-3260.
Resin Transfer Molding
A proposal to the Ohio Technology Action Fund, entitled "Resin Transfer Molding of High-Temperature Polyimides for Low-Cost Composite Manufacturing" is being submitted by Maverick Corporation, General Electric Aircraft Engines, BF Goodrich, GKN, the Air Force Materials Lab and the GRC Polymers Branch. This proposal addresses the commercialization of low melt viscosity polyimides, developed by Maverick under a GRC funded Phase II SBIR and NASA GRC as part of the 3rd Generation Reusable Launch Vehicle Technology Program, for aerospace and non-aerospace and non-aerospace applications. Use of Resin Transfer Molding can reduce high temperature composite manufacturing costs by as much as 50%, which could open up new markets for these materials in such industries as automotive and transportation. Point of Contact: 5150/Michael A. Meador, 3-9518.