NASA - National Aeronautics and Space Administration

Metallography Laboratory
Photo credit: NASA

The Materials Evaluation Laboratories (MEL) provide science and engineering services to Johnson Space Center (JSC), industrial organizations, NASA and other government agencies, educational and research institutions including those supporting NASA spaceflight and technology development programs.  We provide analytical capabilities used in the analysis and evaluation of space flight hardware, failure analysis of flight and non-flight hardware, materials properties testing and advanced materials development. The MEL is staffed with scientists, engineers, and technologists who have degrees and expertise in:

• Chemistry
• Materials Science and Engineering
• Mechanical Engineering
• Metallurgical Engineering
• Non Destructive Evaluation

Scanning Electron Microscopy Laboratory (SEM)

Scanning Electron Microscopy Laboratory
Photo credit: NASA

The SEM contains a Cold Field Emission SEM (Hitachi S-4800) and a Variable Pressure Schottky SEM (Zeiss Supra 55VP) capable of imaging electrically conductive and non-conductive specimens to 1 nm resolution.  The laboratory capabilities include:

• Secondary/backscatter imaging
• Energy Dispersive Spectroscopy (EDS)
• Electron Backscatter Diffraction (EBSD)
• Scanning Transmission Electron Microscopy (STEM)
• Carbon and Precious Metal Thermal /Sputter Coaters

The Hitachi SEM, has the capability of producing high resolution images at low accelerating voltages that enable the more difficult examination of nonmetallic and nonconductive specimens like nanotubes. Both SEM instruments are also outfitted with energy dispersive spectrometry (EDS) that allows the determination of the elements of the sample. This capability is used for identifying the composition of metallic alloys, contamination and coatings. EDS operates by collecting the energy received back from the excited electrons as they drop back to lower energy electron shells and converting the energy to a digital pulse. The resulting EDS spectrum is used to identify the element.

Polymer Laboratory - 150 kN Load Frame
Photo credit: NASA

Polymer/Adhesive Laboratory

The Polymer Laboratory has the capability of performing tensile, lap shear, and/or compressive testing of materials and structural components at elevated or cold temperatures.  This allows bonded lap shears to be pulled to failure at different temperatures and also allows for testing of different components that need to be exposed to a range of temperatures. The laboratory is equipped to research aspects of cutting and bonding most tile materials used by the space programs. The equipment consists of:

• 150 kN load frame
• Environmental chamber (-250 F to 800F)
• Shore hardness measurement for polymers (Shore A, D and M)
• Methods for cutting and bonding numerous nonmetallic materials
• Band saw dedicated to cutting Thermal Protection System (TPS) tiles, ceramic and composite materials

Metallography Laboratory

The Metallography Laboratory conducts investigations of material microstructures and provides overall photography in support of various failure analyses and materials evaluations. During failure analysis, where a broken part is documented with digital photography in the as-received condition before a section of the material is cut into a manageable size, and then mounted in a resin disk. The disk is then polished to a mirror finish that can be analyzed for grain size, flaw detection and coating thickness in the metallograph. The laboratory services include:

• Abrasive cut-off & Precision Diamond Saws
• Mounting/Polishing/Etching
• Hardness Testers (bench top and portable)
• Field Metallography
• Inverted, Stereo and Upright Microscopy
• Reflective Brightfield, Darkfield, DIC, C-DIC, Polarized, Transmitted
• Digital Photography
• Imagery & Dimensional Analysis

Infrared Thermography Inspection
Photo credit: NASA

Nondestructive Evaluation (NDE) Laboratory

The NDE laboratory provides surface and volumetric evaluations using various non-destructive testing methods and techniques that do not destroy the hardware. We assist in failure analysis investigations, reverse engineering, and manufacturing of metallic and non-metallic materials.

The laboratory services include:

Radiographic Testing (RT)

• Computed Tomography (CT)
• Digital Radiography (DR)
• Standard Film Radiography

Ultrasonic Testing (UT)

• Phased Array Ultrasonic Testing (PAUT)
• C-scan Ultrasonic Testing
• Conventional UT

Infrared Thermography Inspection (IR)

• Flash Infrared Thermography Testing (FIR)
• Infrared Thermography Testing

Remote Evaluation Techniques

• Laser Shearography
• ARAMIS 3-D Image Correlation Photogrammetry
• High Speed Imagery

Eddy Current Testing (ET)

• Array Eddy Current Testing (AET)
• Conventional Eddy Current Testing (ET)

Liquid Penetrant & Magnetic Particle Inspection (PT & MT)

• Fluorescent and visible mediums for both methods

Analytical Chemistry Laboratory

Analytical Chemistry Laboratory
Photo credit: NASA

The ACL contains analytical instruments that are used to determine thermal, optical and chemical properties of organic materials. The primary functions of the lab are to identify unknown compounds and determine the properties of advanced or developmental materials. Several of the chemical analysis instruments generate data that can be searched in known database libraries to identify unknown compounds.

The laboratory services include:

Chemical Analysis

• Fourier Transform Infrared Spectrometry (FT-IR)
• Pyrolysis Gas Chromatography/Mass Spectrometry
• UV-Vis-NIR
• Raman Spectrometry
• Near Infrared Photoluminescence (NIRPL)

Thermal Analysis

• Differential Scanning Calorimetry (DSC)
• Thermogravimetric Analysis (TGA)TGA-MS-FTIR
• Dynamic Mechanical Analysis (DMA)
• Laser Flash Technique thermal diffusivity)
• Rheology

Other Analysis

• BET Surface Area Porosity Analyzer
• Optical Instruments
• Wet Chemistry Techniques
• 4-point Probe Conductivity Meter

Nanotechnology

The Applied Nanotechnology Team is a specialized group with expertise in the characterization of nanomaterials. This group utilizes a variety of instrumentation within the MEL, and partners laboratories to perform nanomaterial evaluations. The team has published a characterization protocol for single wall carbon nanotubes, organized NASA/NIST workshops in metrology and worked with ANSI to establish international nanotechnology standards.

Capabilities include:

• Microscopy – SEM, TEM, AFM
• Optical Spectroscopy – UV-Vis-NIR, FTIR, NIR-PL, Raman
• Thermal Analysis
• Mass Spectroscopy
• Photoelectron Spectroscopy
• X-ray Diffraction
• Electron Beam Diffraction