Graded composition/property insert materials are proposed for two step brazing of bulk silicon nitride to ductile iron, 4340 steel or warpalloy. the insert materials provide graded mechanical and thermal expansion properties between those of silicon nitride and those of the metallic material of… More

Research on an ultra high deposition rate, reduced deposition rate, reduced heat input , single pass welding process for heavy section steels is proposed. the process uses metal powder additions, in combination with a consumable welding electrode, to increase the total metal deposition rate of a… More

Development of an accelerated test methodology for near-threshold corrosion fatigue testing of welded shipbuilding steels is proposed. mil s-24645 class 3 hsla steel will be used for initial demonstration of the technique. pre-test materials characteristization will include microstructural features… More

A systematic study of the effect of controlled residual and intentional alloying additons and welding preheat on the weldability of mil-a-12560 armor is proposed. baseline material will be commercial heat of mil-a-12560. multiple laboratory scale heats will be prepared with controlled levels of… More

Research on improved thermally sprayed aluminum non-skid coatings is proposed. the improved coatings are aluminum-aluminum oxide metal matrix composites rather than pure aluminum. compared to conventional thermally sprayed pure aluminum coatings, the composites have demonstrated higher hardness and… More

Model metal matrix composite materials will be fabricated and tested in a study of the influence of microstructural parameters on fracture toughness. microstructural parameters to be varied at two levels in a statistically designed experiment include the degree of chemical bonding between the matrix… More

This project will use highly instrumented microscale laser test facilities for real-time measurement of vaporization/oxidation phenomena at temperatures up to 4000 deg f. the technique will be applied to four model composite systems, two oxidation-resistant carboncarbon composite systems and two… More

The project will examine techniques for growth of high purity iron whiskers of various morphologies from the vapor phase. precursor species and deposition process parameters will be systematically varied. product morphological, chemical and physical characteristics, particularly magnetic properties,… More

This project will examine the utility of alternative metal and nonmetal precursor species for chemical vapor infiltration of hfc and hfb2 into carbon fiber and boron filament preforms, respectively. in particular, the use of precursor species which react slowly to deposite the matrix material at… More

Effective use of intermetallics in composite and honeycomb structures will require high strength, high quality foil starting materials. direct fabrication of tial foils by chemical vapor deposition onto sacrificial tape substrates is proposed. two techniques, high temperature chemical vapor… More

The proposed work will examine synthesis of high purity refractory metal alloy particulates and whiskers for use as ductile reinforcing phases in advanced intermetallic matrix composites. prototype ductile reinforcing phases will be prepared and thermochemical compatibility tests will be performed… More

The proposed work will examine possible approaches toward a metallic inhibition/protection system for carbon-carbon composites. the effort will be a combined theoretical/experimental study to analyze and test options for inhibition of matrices and sealing the nearsurface regions using metal or alloy… More

Refractory boride matrices (zrb(2), hfb(2)) reinforced with high modulus carbon fibers show promise as ultrahigh temperature structural material. the maximum use temperature is limited by the mutual reactivity of the constituent materials and the formation of liquid phases with significantly lower… More

The proposed research will examine the utility of duplex coatings, consisting of an inner, weakly-bonded coating immediately adjacent to the fiber and an outer, chemical-compatibility coating adjacent to the matrix. model duplex coating systems, where each constituent material is thermochemically… More

The proposed research will examine the use of model refractory and light metal coatings on carbon-carbon composite substrates for the multiple functionalities of resistance to atomic oxygen effects expected in low earth orbit, high power c.w. laser effects before and after exposure to atomic oxygen,… More

The proposed work will examine alternative methods for synthesis of high purity refractory beryllides in either powder, foil or bulk form. analytical efforts and process modeling will focus on those methods which are capable of producing two-component intermetallic compounds of the required… More

The proposed research will examine methods for gmaw welding of al/sic(p) composite base materials with small diameter extruded al/sic(p) composite welding electrode wires. feasibility of the extrusion process for producing the required small diameter wires and butt welding of extruded lengths to… More

The proposed phase i research project will examine alternative methods for synthesis of y(2)o(3) and y(2)o(3)-based coatings on ceramic fibers and metallic particles for use in ceramic and intermetallic brittle matrix composites. synthesis methods and heat treatment conditions will be varied to… More

Direct synthesis of nbal alloy foils by chemical vapor deposition onto inert substrates is proposed. inorganic, i.e. halide, and mixed inorganic/organometallic source gases will be used to synthesize pure nb, pure al, and intermetallic compounds nb3al and several compositions bracketing nbal3.… More

The phase i research will produce and evaluate ti(5)si(3)-based monofilaments having improved thermochemical and thermochemical compatibility in gamma titanium aluminide matrices. al-containing monofilament compositions will be prepared by direct chemical vapor deposition onto small diameter… More

The overall object of this program is to develop an economic process for thenear net shape fabrication of sic/sic ceramic composites by liquid silicon infiltration of porous sic fiber/carbon matrix performs. the primary objective of the phase i effort is to demonstrate that a silicon melt… More

The proposed phase i research will examine two novel processes for improving the uniformity and density of ceramic matrix chemical vapor infiltration (cvi). both methods involve the uniform selective deposition of matrix material starting at the fiber matrix interface. one technique involves the… More

The phase i research will examine novel methods for application of single phase and composite glass and glass-matrix coatings for oxidation and erosion resistance improvement of afr700b matrix composites. single phase and composite coatings will be applied to composite substrates by sol-gel,… More

The proposed research will conduct both thermochemical and thermomechanical analyses of candidate internal and external coating materials and configurations for sic monofilaments. analyses will consider single and duplex coatings to be deployed in a range of titanium alloy and titanium intermetallic… More

Graphite/glass composites offer lightweight, highly conductive, survivable radiators that can improve the maximum temperature and energy efficiency of space nuclear power systems. MSNW will develop a preliminary radiator design, fabricate subcomponent materials, and experimentally determine critical… More

The phase i research will examine a simplified purification scheme for s and for si contaminated p precursors. the process uses chemical techniques as well as low temperature fractional distilla- tion to effect separation of high purity ph3 and to minimize con- tamination from container materials+… More

Shape memory alloys (SMA's) have been a major element of the intelligent materials and structures research effort, and actuators for the control of structures have been designed on the basis of their unique thermomechanical behavior. The design of SMA force and displacement actuators requires a… More

The Phase I research will produce and evaluate continuous TiC1-x monofilaments having improved thermochemical and thermomechanical compatibility in high Ti content (beta alloys, orthorhombics, and a-2 titanium aluminide) matrices. Continuous binary carbide monofilament compositions will be prepared… More

The proposed Phase I research project will quantify the sources of contamination in powder/binder processing of sapphire monofilament reinforced gamma TiAl metal matrix composites as currently practiced, demonstrate alternative reduced contamination binder systems and removal methods, and examine… More

Metal/Bismaleimide composite couples will be tested using systematic variation of electrolyte composition, atmosphere, and metal composition to establish the damage mechanism(s) for couples exposed to salt water and for correlation with observed field behavior. Scanning electron microscopy… More

The work proposed here addresses key challenges to the development of brazed carbon-carbon joints for space structure thermal management applications. Interlayer materials are sought which will minimize thermal resistance across brazed joints, maintain good shear strength characteristics, have low… More

The diborides of hafnium and zirconium are highly resistant to ablation at extreme temperatures under oxidizing conditions but are brittle and have poor thermal shock resistance. A potential solution to this problem is reinforcment with diboride fibers to create tough, thermal shock resistant… More

The proposed Phase I program addresses key challenges to the development of ceramic-based mechanical fasteners for Naval aircraft applications. Specific applications of interest for the ceramic fasteners include high temperature joining regions of aircraft such as in the vicinity of engine exhaust,… More

The objectives of this program are to study the partial or complete conversion of small diameter, high strength carbon fiber multifilament tows to SiC and to understand the relationship of the conversion mechanisms to the morphology and properties of the resultant fibers. The project will utilize… More

Current tactical missile rocket nozzles provide adequate performance, but it is expected that significant improvements can be realized if the present generation nozzles are replaced with composite nozzles composed of carbon fibers and hafnium or zirconium-based ceramic matrix materials. Present… More

The fins of Army hypervelocity missiles are situated within the exhaust plumes. This creates a unique fin erosion environment consisting of a combination of high temperature gases plus particulates of aluminum oxide solid fuel particles. Several approaches are available for the design of low… More

Carbon-carbon (C-C) composites have properties that make them attractive for increasing the efficiency of a variety of commercial and industrial combustion systems and heat-utilization processes. Increased efficiency will lower the emission of harmful products for direct improvements in … More

Silicon carbide fiber reinforced titanium matrix (SiC/Ti) composites offer lightweight, high strength replacement materials for superalloys in gas turbine engines and airframes. Titanium matrices tend to react with SiC and form reaction products that exhibit properties which are very different from… More

The proposed Phase I project will examine potential low-cost, high-rate processes for synthesizing hafnium boride and hafnium nitride composite matrices from liquid precursors. Several of the most cost-effective precursor material combinations will be comparatively evaluated in terms of product… More

Current tactical missile rocket nozzles provide adequate performance, but it is expected that significant improvements can be realized if the present generation nozzles are replaced with composite nozzles composed of carbon fibers and hafnium or zirconium-based ceramic matrix materials. Present… More

The proposed Phase I project will examine low cost, low density composition gradient materials for zero-erosion rocket nozzles for use at the extreme temperatures encountered with aluminized propellants. The materials system consists of a C fiber-reinforced HfC matrix composite substrate overcoated… More

The proposed Phase II research will build on a recent breakthrough development by MSNW, Inc. of a reinforced adhesive chemically compatible with oxide/oxide CMCs and demonstrating through thickness tensile strengths greater than 1 ksi. The Phase I projectdemonstrated the potential of this adhesive… More

The proposed Phase II research will build on a recent breakthrough development by MSNW, Inc. of a reinforced adhesive chemically compatible with oxide/oxide CMCs and demonstrating through thickness tensile strengths greater than 1 ksi. The Phase I projectdemonstrated the potential of this adhesive… More

Simple, affordable, durable repair methods that can be performed in the field are required for high temperature radar absorbing material (RAM) coatings. The proposed Phase I research will build upon previous RAM coating research at MSNW, Inc. The projectwill develop and demonstrate unique, robust… More

The Phase I project developed an extensive database on electrical properties of candidate repair materials covering a wide range of thermal expansion coefficients from those of ceramic composites to those of superalloys. The Phase II project will develop, optimize and demonstrate unique, robust RAM… More

In the proposed program, MSNW, Inc. will address critical materials problems associated with the hot gas seals required with two novel designs for the mechanical attachment of reusable space access vehicle thermal protection systems (TPS). The Boeing Company (Boeing Phantom Works), in conjunction… More

Two attachment designs for either carbide-based structural ceramic matrix composite TPS panels or oxide-based TPS based upon CMC-wrapped low density tiles have been identified as candidates for further development. Both designs require Nextel 720 fabric or braid faced flexible gap filler seals. The… More