Search NASA⌕ Search

SEARCH · Search NASA

Results for “engineered matrix composites”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Evaluation of Graphite Fiber/Polyimide PMCs from Hot Melt versus Solution Prepreg

Carbon fiber reinforced high temperature polymer matrix composites (PMC) have been extensively investigated as potential weight reduction replacements of various metallic components in next generation high performance propulsion rocket engines. The initial phase involves development of comprehensive composite material-process-structure-design-property in-service performance correlations and database, especially for a high stiffness facesheet of various sandwich structures. Overview of the program plan, technical approaches and current multi-team efforts will be presented. During composite fabrication, it was found that the two large volume commercial prepregging methods (hot-melt vs. solution) resulted in considerably different composite cure behavior. Details of the process-induced physical and chemical modifications in the prepregs, their effects on composite processing, and systematic cure cycle optimization studies will be discussed. The combined effects of prepregging method and cure cycle modification on composite properties and isothermal aging performance were also evaluated.

Shin, Eugene E.↗
NASA NTRS2002

Evaluation of Graphite Fiber/Polyimide PMCs from Hot Melt vs Solution Prepreg

Carbon fiber reinforced high temperature polymer matrix composites (PMC) have been extensively investigated as potential weight reduction replacements of various metallic components in next generation high performance propulsion rocket engines. The initial phase involves development of comprehensive composite material-process-structure-design-property-in-service performance correlations and database, especially for a high stiffness facesheet of various sandwich structures. Overview of the program plan, technical approaches and current multi-team efforts will be presented. During composite fabrication, it was found that the two large volume commercial prepregging methods (hot-melt vs. solution) resulted in considerably different composite cure behavior. Details of the process-induced physical and chemical modifications in the prepregs, their effects on composite processing, and systematic cure cycle optimization studies will be discussed. The combined effects of prepregging method and cure cycle modification on composite properties and isothermal aging performance were also evaluated.

Shin, E. Eugene↗
NASA NTRS1992

Combustor materials requirements and status of ceramic matrix composites

The HSCT combustor will be required to operate with either extremely rich or lean fuel/air ratios to reduce NO(x) emission. NASA High Speed Research (HSR) sponsored programs at Pratt & Whitney (P&W) and GE Aircraft Engines (GEAE) have been studying rich and lean burn combustor design approaches which are capable of achieving the aggressive HSCT NO(x) emission goals. In both of the combustor design approaches under study, high temperature (2400-3000 F) materials are necessary to meet the HSCT emission goals of 3-8 gm/kg. Currently available materials will not meet the projected requirements for the HSCT combustor. The development of new materials is an enabling technology for the successful introduction to service of the HSCT.

Hecht, Ralph J.↗
NASA NTRSDate not supplied

The Development and Use of a Natural Gas / Oxygen Burner Rig for Environmental Barrier Coating and Ceramic Matrix Composite Technology Maturation

This work outlines the development of a new natural gas/oxygen (NG/O2) fueled combustion rig located at the NASA Glenn Research Center for high-temperature environmental durability studies of advanced materials and components at atmospheric pressure. The NG/O2 burner rig can simulate the high-temperature, high-heat flux, and high-velocity thermal environments encountered in gas turbine engines. It also provides the capability to study environmental effects such as water vapor and other foreign contaminants relevant to these applications. The rig is anticipated to bridge the gap between other laboratory methods such as furnaces, jet-fueled burner rigs, high-heat flux lasers, and more expensive engine rig testing. The NG/O2 rig is expected to have maximum sample temperature capabilities over 3,000°F (1,649°C) and result in higher water vapor content compared to our Mach 0.3 to Mach 1.0 jet-A burner rigs which is important for characterizing current and next-generation environmental barrier coatings. This paper will provide an overview of the development of the NG/O2 burner rig, initial characterization, and current research and development efforts on environmental barrier coated ceramic matrix composites.

Burner rig↗
NASA NTRS2013

Engineered Polymer Composites Through Electrospun Nanofiber Coating of Fiber Tows

Toughening and other property enhancements of composite materials are typically implemented by-modifying the bulk properties of the constituents, either the fiber or matrix materials. This often leads to difficulties in processing and higher material costs. Many composites consist of tows or yarns (thousands of individual fibers) that are either filament wound or processed into a fabric by weaving or braiding. The matrix material can be added to the tow or fabric before final processing, resulting in a prepreg material, or infused into the fiber material during final processing by a variety of methods. By using a direct electrospun deposition method to apply thermoplastic nanofiber to the surface of the tows, the tow-tow interface in the resulting composite can be modified while using otherwise conventional materials and handling processes. Other materials of interest could also be incorporated into the electrospun precursor.

toughening↗
DOE OSTI2024

Assessing Composite Structure in Metal–Organic Framework-Polymer Mixed-Matrix Membranes

Metal-organic frameworks (MOFs) are renowned for their tunable structure, porosity, and internal chemistry, with demonstrated applications in molecular separations, storage, and conversion. While they are widely usable, the powdery characteristics of MOF materials can be limiting for large-scale processing and implementation in devices. Incorporating MOF particles into polymer supports affords engineering solutions to overcome these issues, yet the nature of the resulting composites is difficult to assess. Here, in this work, we present spectroscopic and calorimetric methods that we believe help establish a holistic physicochemical picture of the composite structure using a series of Zr MOFs with different pore sizes as a testbed. Power law decays are observed in X-ray scattering profiles in low q-space ranging between 2.4 and 3.3, which we interpret as changes in scattering due to polymer infiltrating MOF particles. This interpretation is supported by solid-state nuclear magnetic resonance spectroscopy and differential scanning calorimetry measurements that identify populations of the MOF-associated polymer. Additionally, positron annihilation lifetime spectroscopy measurements collected on a series of composites with different MOF-polymer ratios show multiple decay constants, each correlated to a different free volume elements. In combination with the spectroscopic, calorimetric, and scattering results, we utilize the trends in decay constants as a function of polymer mass fraction to hypothesize a polymer infiltration mechanism whereby large pores are preferentially filled, followed by small pores and, later still, interstitial spaces between particles. Even with vigorous investigation of polymer, MOF, and interface characteristics, the complex and heterogeneous nature of the composites makes absolute structural assertions difficult. We envision that the approaches demonstrated here will be a useful foundation to assess and ultimately guide the design of future MOF-polymer composites.

36 MATERIALS SCIENCE↗
NASA NTRS2002

Ceramic Composite Intermediate Temperature Stress-Rupture Properties Improved Significantly

Silicon carbide (SiC) composites are considered to be potential materials for future aircraft engine parts such as combustor liners. It is envisioned that on the hot side (inner surface) of the combustor liner, composites will have to withstand temperatures in excess of 1200 C for thousands of hours in oxidizing environments. This is a severe condition; however, an equally severe, if not more detrimental, condition exists on the cold side (outer surface) of the combustor liner. Here, the temperatures are expected to be on the order of 800 to 1000 C under high tensile stress because of thermal gradients and attachment of the combustor liner to the engine frame (the hot side will be under compressive stress, a less severe stress-state for ceramics). Since these composites are not oxides, they oxidize. The worst form of oxidation for strength reduction occurs at these intermediate temperatures, where the boron nitride (BN) interphase oxidizes first, which causes the formation of a glass layer that strongly bonds the fibers to the matrix. When the fibers strongly bond to the matrix or to one another, the composite loses toughness and strength and becomes brittle. To increase the intermediate temperature stress-rupture properties, researchers must modify the BN interphase. With the support of the Ultra-Efficient Engine Technology (UEET) Program, significant improvements were made as state-of-the-art SiC/SiC composites were developed during the Enabling Propulsion Materials (EPM) program. Three approaches were found to improve the intermediate-temperature stress-rupture properties: fiber-spreading, high-temperature silicon- (Si) doped boron nitride (BN), and outside-debonding BN.

Morscher, Gregory N.↗
NASA NTRS2017

Advanced Environmental Barrier Coating Development for SiC-SiC Ceramic Matrix Composite Components

This presentation reviews the NASA advanced environmental barrier coating (EBC) system development for SiC-SiC Ceramic Matrix Composite (CMC) combustors particularly under the NASA Environmentally Responsible Aviation, Fundamental Aeronautics and Transformative Aeronautics Concepts Programs. The emphases have been placed on the current design challenges of the 2700-3000F capable environmental barrier coatings for low NOX emission combustors for next generation turbine engines by using advanced plasma spray based processes, and the coating processing and integration with SiC-SiC CMCs and component systems. The developments also have included candidate coating composition system designs, degradation mechanisms, performance evaluation and down-selects; the processing optimizations using TriplexPro Air Plasma Spray Low Pressure Plasma Spray (LPPS), Plasma Spray Physical Vapor Deposition and demonstration of EBC-CMC systems. This presentation also highlights the EBC-CMC system temperature capability and durability improvements under the NASA development programs, as demonstrated in the simulated engine high heat flux, combustion environments, in conjunction with high heat flux, mechanical creep and fatigue loading testing conditions.

CMAS↗
DOE OSTI2024

Confinement of excited states in two-dimensional, in-plane, quantum heterostructures

Two-dimensional (2D) semiconductors are promising candidates for optoelectronic application and quantum information processes due to their inherent out-of-plane 2D confinement. In addition, they offer the possibility of achieving low-dimensional in-plane exciton confinement, similar to zero-dimensional quantum dots, with intriguing optical and electronic properties via strain or composition engineering. However, realizing such laterally confined 2D monolayers and systematically controlling size-dependent optical properties remain significant challenges. Here, we report the observation of lateral confinement of excitons in epitaxially grown in-plane MoSe 2 quantum dots (~15-60 nm wide) inside a continuous matrix of WSe 2 monolayer film via a sequential epitaxial growth process. Various optical spectroscopy techniques reveal the size-dependent exciton confinement in the MoSe 2 monolayer quantum dots with exciton blue shift (12-40 meV) at a low temperature as compared to continuous monolayer MoSe 2 . Finally, single-photon emission (g 2 (0) ~ 0.4) was also observed from the smallest dots at 1.6 K. Our study opens the door to compositionally engineered, tunable, in-plane quantum light sources in 2D semiconductors.

42 ENGINEERING↗
NASA NTRS2023

The Development and Use of a Natural Gas / Oxygen Burner Rig for Environmental Barrier Coating and Ceramic Matrix Composite Technology Maturation

This work outlines the development of a new natural gas/oxygen (NG/O 2 ) fueled combustion rig located at the NASA Glenn Research Center for high-temperature environmental durability studies of advanced materials and components at atmospheric pressure. The NG/O 2 burner rig can simulate the high-temperature, high-heat flux, and high-velocity thermal environments encountered in gas turbine engines. It also provides the capability to study environmental effects such as water vapor and other foreign contaminants relevant to these applications. The rig is anticipated to bridge the gap between other laboratory methods such as furnaces, jet-fueled burner rigs, high-heat flux lasers, and more expensive engine rig testing. The NG/O 2 rig is expected to have maximum sample temperature capabilities over 3,000°F (1,649°C) and result in higher water vapor content compared to our Mach 0.3 to Mach 1.0 jet-A burner rigs which is important for characterizing current and next-generation environmental barrier coatings. This paper will provide an overview of the development of the NG/O 2 burner rig, initial characterization, and current research and development efforts on environmental barrier coated ceramic matrix composites.

Burner rig↗
NASA NTRS1982

Fabrication of advanced composites

Fabrication techniques for manufacturing advanced composite structures with continuous and short filaments in desired orientations and consolidation within the plies of the structure are described and analyzed. Attention is given to vacuum bag molding, autoclave molding, matched die consolidation of B/Al, B/epoxy, and graphite/epoxy composites, matched die molding of chopped fiber prepregs, thermal expansion molding, braiding, filament winding, sandwich fabrication, and pultrusions. Step-by-step preparation of resin-matrix composites is detailed, including automatic and semiautomatic lay-ups, and problems of quality control are discussed. The review is intended as an engineering aid for choices between competitive designs, and comprises factors other than technical features alone, such as cost effectiveness, ease of inspection, and economics of maintenance.

Meade, L. E. R.↗
NASA NTRS2004

An Assessment of Variability in the Average Tensile Properties of a Melt-Infiltrated SiC/SiC Composite

Woven SiC/SiC Ceramic Matrix Composites (CMCs), manufactured by the slurry-cast, melt-infiltration process are under consideration as combustor liner materials in aircraft gas turbine engines. Tensile properties (elastic modulus, proportional limit strength, in-plane tensile strength and strain to failure) of the CMC, manufactured during two separate time periods (9/99 and 1/01) were determined at 816 and 1024 C by conducting tensile tests on specimens machined from the CMC plates. A total of 24 tensile tests were conducted for each temperature and CMC variant combination. In this study average tensile properties of the two cMC variants were statistically compared to evaluate significant differences, if any, within the CMC's properties.

Kalluri, Sreeramesh↗
NASA NTRS2020

Advancing Development of Environmental Barrier Coatings Resistant to Attack by Molten Calcium-Magnesium-Aluminosilicate (CMAS)

Ceramic matrix composites (CMCs) are a leading material system to replace metal-based parts in the hot-section of air-breathing turbine engines to improve fuel efficiency in aircraft engines. CMCs have higher temperature capabilities and lower density compared with traditional metallic structural materials. However, silicon-based CMCs are susceptible to oxidation in the harsh combustion environment encountered in turbine engines. Consequently, environmental barrier coatings (EBCs) are being developed to protect CMC components to improve durability and extend service life of CMCs. Sand, volcanic ash and other particulate debris, which are generally comprised of calcium-magnesium-aluminosilicate (CMAS) and other trace oxides, are routinely ingested by aircraft engines. At temperatures above 1200°C, CMAS particulates melt. Near target operating temperatures (~1500°C) of future CMC-based aircraft engines, molten CMAS behaves like a viscous melt that can infiltrate and chemically interact with protective coatings. These interactions can cause premature failure of the EBC system and ultimately the overall CMC engine component. Degradation of candidate EBC materials by molten CMAS will be presented with a focus on recent work, as well as methods of evaluating the complex high-temperature materials interactions, underway at NASA Glenn Research Center.

Wiesner, Valerie L.↗
NASA NTRS2015

Update on CMH-17 Volume 5: Ceramic Matrix Composites

CMC components are projected to enter service in commercial aircraft in 2016. A wide range of issues must be addressed prior to certification of this hardware. The Composite Materials Handbook-17, Volume 5 on ceramic matrix composites is being revised to support FAA certification of CMCs for hot structure and other elevated temperature applications. The handbook supports the development and use of CMCs through publishing and maintaining proven, reliable engineering information and standards that have been thoroughly reviewed. Volume 5 will contain detailed sections describing CMC materials processing, design analysis guidelines, testing procedures, and data analysis and acceptance. A review of the status of and plans for two of these areas, which are being addressed by the M and P Working Group and the Testing Working Group, will be presented along with a timeline for the preparation of CMH-17, Volume 5.

design↗
NASA NTRS2007

Improving Turbine Performance with Ceramic Matrix Composites

Under the new NASA Fundamental Aeronautics Program, efforts are on-going within the Supersonics Project aimed at the implementation of advanced SiC/SiC ceramic composites into hot section components of future gas turbine engines. Due to recent NASA advancements in SiC-based fibers and matrices, these composites are lighter and capable of much higher service temperatures than current metallic superalloys, which in turn will allow the engines to operate at higher efficiencies and reduced emissions. This presentation briefly reviews studies within Task 6.3.3 that are primarily aimed at developing physics-based concepts, tools, and process/property models for micro- and macro-structural design, fabrication, and lifing of SiC/SiC turbine components in general and airfoils in particular. Particular emphasis is currently being placed on understanding and modeling (1) creep effects on residual stress development within the component, (2) fiber architecture effects on key composite properties such as design strength, and (3) preform formation processes so that the optimum architectures can be implemented into complex-shaped components, such as turbine vanes and blades.

DiCarlo, James A.↗
NASA NTRS2011

Phase Stability and Thermal Conductivity of Composite Environmental Barrier Coatings on SiC/SiC Ceramic Matrix Composites

Advanced environmental barrier coatings are being developed to protect SiC/SiC ceramic matrix composites in harsh combustion environments. The current coating development emphasis has been placed on the significantly improved cyclic durability and combustion environment stability in high-heat-flux and high velocity gas turbine engine environments. Environmental barrier coating systems based on hafnia (HfO2) and ytterbium silicate, HfO2-Si nano-composite bond coat systems have been processed and their stability and thermal conductivity behavior have been evaluated in simulated turbine environments. The incorporation of Silicon Carbide Nanotubes (SiCNT) into high stability (HfO2) and/or HfO2-silicon composite bond coats, along with ZrO2, HfO2 and rare earth silicate composite top coat systems, showed promise as excellent environmental barriers to protect the SiC/SiC ceramic matrix composites.

Benkel, Samantha↗
NASA NTRS1997

Design Protocols and Analytical Strategies that Incorporate Structural Reliability Models

Ceramic matrix composites (CMC) and intermetallic materials (e.g., single crystal nickel aluminide) are high performance materials that exhibit attractive mechanical, thermal, and chemical properties. These materials are critically important in advancing certain performance aspects of gas turbine engines. From an aerospace engineers perspective the new generation of ceramic composites and intermetallics offers a significant potential for raising the thrust/weight ratio and reducing NO(sub x) emissions of gas turbine engines. These aspects have increased interest in utilizing these materials in the hot sections of turbine engines. However, as these materials evolve and their performance characteristics improve a persistent need exists for state-of-the-art analytical methods that predict the response of components fabricated from CMC and intermetallic material systems. This need provided the motivation for the technology developed under this research effort. Continuous ceramic fiber composites exhibit an increase in work of fracture, which allows for 'graceful' rather than catastrophic failure. When loaded in the fiber direction these composites retain substantial strength capacity beyond the initiation of transverse matrix cracking despite the fact that neither of its constituents would exhibit such behavior if tested alone. As additional load is applied beyond first matrix cracking, the matrix tends to break in a series of cracks bridged by the ceramic fibers. Any additional load is born increasingly by the fibers until the ultimate strength of the composite is reached. Thus modeling efforts supported under this research effort have focused on predicting this sort of behavior. For single crystal intermetallics the issues that motivated the technology development involved questions relating to material behavior and component design. Thus the research effort supported by this grant had to determine the statistical nature and source of fracture in a high strength, NiAl single crystal turbine blade material; map a simplistic future strength envelope of the material; develop a statistically based reliability computer algorithm; verify the reliability model and computer algorithm-, and model stator vanes for rig tests. Thus establishing design protocols that enable the engineer to analyze and predict the mechanical behavior of ceramic composites and intermetallics would mitigate the prototype (trial and error) approach currently used by the engineering community. The primary objective of the research effort supported by this short term grant is the continued creation of enabling technologies for the macro-analysis of components fabricated from ceramic composites and intermetallic material systems. The creation of enabling technologies aids in shortening the product development cycle of components fabricated from the new high technology materials.

Duffy, Stephen F.↗
NASA NTRS1997

Design Protocols and Analytical Strategies that Incorporate Structural Reliability Models

Ceramic matrix composites (CMC) and intermetallic materials (e.g., single crystal nickel aluminide) are high performance materials that exhibit attractive mechanical, thermal and chemical properties. These materials are critically important in advancing certain performance aspects of gas turbine engines. From an aerospace engineer's perspective the new generation of ceramic composites and intermetallics offers a significant potential for raising the thrust/weight ratio and reducing NO(x) emissions of gas turbine engines. These aspects have increased interest in utilizing these materials in the hot sections of turbine engines. However, as these materials evolve and their performance characteristics improve a persistent need exists for state-of-the-art analytical methods that predict the response of components fabricated from CMC and intermetallic material systems. This need provided the motivation for the technology developed under this research effort. Continuous ceramic fiber composites exhibit an increase in work of fracture, which allows for "graceful" rather than catastrophic failure. When loaded in the fiber direction, these composites retain substantial strength capacity beyond the initiation of transverse matrix cracking despite the fact that neither of its constituents would exhibit such behavior if tested alone. As additional load is applied beyond first matrix cracking, the matrix tends to break in a series of cracks bridged by the ceramic fibers. Any additional load is born increasingly by the fibers until the ultimate strength of the composite is reached. Thus modeling efforts supported under this research effort have focused on predicting this sort of behavior. For single crystal intermetallics the issues that motivated the technology development involved questions relating to material behavior and component design. Thus the research effort supported by this grant had to determine the statistical nature and source of fracture in a high strength, NiAl single crystal turbine blade material; map a simplistic failure strength envelope of the material; develop a statistically based reliability computer algorithm, verify the reliability model and computer algorithm, and model stator vanes for rig tests. Thus establishing design protocols that enable the engineer to analyze and predict the mechanical behavior of ceramic composites and intermetallics would mitigate the prototype (trial and error) approach currently used by the engineering community. The primary objective of the research effort supported by this short term grant is the continued creation of enabling technologies for the macroanalysis of components fabricated from ceramic composites and intermetallic material systems. The creation of enabling technologies aids in shortening the product development cycle of components fabricated from the new high technology materials.

Duffy, Stephen F.↗