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Materials Research and Education Center

BRYAN A. CHIN, DIRECTOR

The Materials Research and Education Center researchers are faculty from the Department of Mechanical Engineering. The principal laboratories are the Composites Manufacturing Laboratory, Materials Characterization Laboratory, Materials Joining Laboratory, Mechanical Properties Laboratory, Optics Laboratory, and Smart Materials Fabrication Laboratory.

COMPOSITES MANUFACTURING LABORATORY

The Composites Manufacturing Laboratory is researching polymer, ceramic, and metal matrix composites and their manufacture (or fabrication). Researchers are trying to find cost-effective ways to better control the effects of fabrication on the performance of composite materials. Casting, injection, extrusion, powder processing, vapor and liquid infiltration techniques are being investigated.

Key equipment includes cold and hot isostatic presses, radio frequency generators for induction heating for metal matrix composite infiltration and casting, chemical vapor infiltration for ceramic- and carbon-matrix composites, high-temperature vacuum furnaces for ceramic composites, heat-treating furnaces, vacuum ovens and infiltration units, compression molding and laminating presses, braiding, weaving and injection-molding machines, extruders, high-torque mixer for mixing polymer-ceramic powders, autoclave for composite fabrication, spinnercoating instrument for nanometer-scale multilayer composites, and electrophoretic deposition for multilayer composites.

MATERIALS CHARACTERIZATION LABORATORY

Materials Characterization Laboratory research includes multiphase NiAl-based intermetallics, structure determination of fluorides, solidification microstructure of IN-718, fabrication and characterization of multidirectional composites, growth and study of thin-film interfaces, nanometer-scale multilayered ceramics, reinforced metal matrix composites with SiC whiskers, structure-property relationship in advanced thermoplastic composites, development of short fiber reinforced advanced carbon/carbon composites, and high-temperature microstructure evolution of tungsten hafnium carbide alloy.

The X-ray diffractometer (XRD) facility and the microscopy laboratories can analyze the structure and microstructure of materials. Materials from the millimeter to the angstrom range and from bulk to surface can be characterized.

Equipment includes optical, scanning, and transmission electron microscopes (reflection and transmission), image analyzers, high-temperature XRDs and stress analysis system for structure characterization, FTIR infrared analyzer, GC/MS and a high-resolution instrument for identifying molecular weights and structure, differential scanning calorimeter, thermoelectric and thermogravimetric analyzers, dilatometer and thermal expansion coefficient measuring instruments, andtorque rheometer for determining rheological properties of polymers and composites.

MATERIALS JOINING LABORATORY

Researchers in the Materials Joining Laboratory investigate welding, vacuum/inert atmosphere brazing, diffusion bonding, transient liquid phase bonding, and weld simulation techniques. Research includes on-line detection and control of weld penetration, design of low-cost/high-reliability sensors for infrared thermography-controlled welding, influence of gas composition variations on weld penetration, adaptive control of gas-metal and submerged-arc welding using infrared thermography, welding of 316 stainless steel containing helium, brazing of alumina dispersion strengthened copper, transient liquid-phase bonding of nickel aluminides, and brazing of carbon-carbon composites.

Equipment includes GTA, GMA and plasma welding power sources, robots, computer-control and data-acquisition equipment, infrared cameras, motion controllers, and Gleeble 1500 weld simulation unit for high-vacuum work, brazing and transient liquid phase bonding, thermomechanical simulation, strain and stress measurements, hot isostatic press for diffusion bonding, and induction units for brazing.

MECHANICAL PROPERTIES LABORATORY

In the Mechanical Properties Laboratory, researchers are investigating the strength of joints produced by novel joining techniques and throughimproved process control of current techniques that fabricate advanced materials into complex structures for many technological applications.

In research on the mechanical properties of composite materials, multidimensional weaving techniques are being developed to produce fiber-reinforced polymer-matrix composites with controlled properties in different orientations. Fiber coatings are being developed to induce fiber debonding, and thus improve toughness of brittle-matrix (ceramic and intermetallic) composites. Researchers are also working on the high-temperature mechanical properties of materials to determine the creep behavior of refractory metal and refractory metal/carbide composites for advanced thermionics power generation in spacecraft.

Equipment includes universal testing machines for tensile, compression, fatigue, creep, and bending properties with computer control, and automated data acquisition and analysis, dynamic mechanical thermal analyzer for mechanical property measurements, vibration measurement, nodal analysis, structural dynamic modification and forced response simulation software, pendulum impact testers, and a drop-weight impact system.

OPTICS LABORATORY

Optics Laboratory researchers are investigating nonlinear and electrooptical properties of novel materials and microstructures, such as organic crystals and waveguide microstructures, for photonics technology applications, including ultrafast electrooptic and all-optical switching, logic operations and frequency conversion. The response time of such switching will be orders of magnitude faster than electronic switching. The electronic properties, excited state lifetimes and possible device applications of novel organic semiconductor materials are being studied.

Instruments for methods such as time-resolved, four-wave mixing, pump-probe, nonlinear interferometry, waveguiding, frequency conversion and Z-scan are used to measure nonlinear optical properties and dynamics of excited states in a short time. The laboratory also has high-power lasers that produce picosecond pulses over a wide range of wavelengths and pulse energies, plus accessories for picosecond optics such as fast photodiode detectors, lock-in amplifier, and oscilloscopes.

SMART MATERIALS FABRICATION LABORATORY

Researchers in the Smart Materials Fabrication Laboratory are designing and developing shape memory alloys and shape memory polymer materials for microminiature sensors and actuators. They use high-vacuum deposition chambers to deposit thin films and single crystals of the shape memory alloys. In research on active vibration control for automotive and aerospace applications, PZT and other piezoelectric materials are being fabricated. New gel polymer materials are being developed for moisture sensors and pH-activated gates and valves. Sol gel formation of PZT actuators is being studied to integrate and miniaturize sensor and actuator components, thereby improvingperformance and increasing protection against failure through redundancy.

Fabrication equipment includes wire and ram EDM, diamond saws, ultrasonic cutters, ultrahigh vacuum and temperature vapor deposition unit, single crystal electron beam heated growth chamber, hot isostatic press for piezoceramics, sol gel spinning and tape casting, vacuum ovens, and heat-treatment furnaces. Characterization equipment includes differential scanning calorimeter, dynamic mechanical thermal analyzer, servohydraulic and offset cam fatigue testing, waveform generators and vibration frequency analyzers, magnetic and electric rheological fluid characterization.

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• Materials Research and Education Center