Composite materials research in support of supersonic propulsion systems

Two engine components, fan blades and exhaust systems, were selected for composite materials development efforts in support of the supersonic cruise aircraft research (SCAR) engine program. The materials selected were boron/aluminum for fan blades and silicon carbide/superalloy sheet for the exhaust system. The current status of the research into applying these two composite materials to SCAR engines is reviewed

Review of status and potential of tungsten-wire: Superalloy composites for advanced gas turbine engine blades

The current status of development of refractory-wire-superalloy composites and the potential for their application to turbine blades in land-based power generation and advanced aircraft engines are reviewed. The data indicate that refractory-wire-superalloy composites have application as turbine blades at temperatures of 2200 F and above

Metal matrix composites for aircraft propulsion systems

Studies of advanced aircraft propulsion systems have indicated that performance gains and operating costs are possible through the application of metal matrix composites. Compressor fan blades and turbine blades have been identified as components with high payoff potential as a result of these studies. This paper will present the current status of development of five candidate materials for such applications. Boron fiber/aluminum, boron fiber/titanium, and silicon carbide fiber/titanium composites are considered for lightweight compressor fan blades. Directionally solidified eutectic superalloy and tungsten wire/superalloy composites are considered for application to turbine blades for use temperatures to 1100 C (2000 F)

Evaluation of silicon carbide fiber/titanium composites

Izod impact, tensile, and modulus of elasticity were determined for silicon carbide fiber/titanium composites to evaluate their potential usefulness as substitutes for titanium alloys or stainless steel in stiffness critical applications for aircraft turbine engines. Variations in processing conditions and matrix ductility were examined to produce composites having good impact strength in both the as-fabricated condition and after air exposure at elevated temperature. The impact strengths of composites containing 36 volume percent silicon carbide (SiC) fiber in an unalloyed (A-40) titanium matrix were found to be equal to unreinforced titanium-6 aluminum-4 vanadium alloy; the tensile strengths of the composites were marginally better than the unreinforced unalloyed (A-70) matrix at elevated temperature, though not at room temperature. At room temperature the modulus of elasticity of the composites was 48 percent higher than titanium or its alloys and 40 percent higher than that of stainless steel

Advanced tungsten fiber-reinforced nickel superalloy

Matrix composition, fabrication technique, and fiber diameter were selected to minimize fiber-matrix reaction and preserve composite strength. Composites may be used in place of superalloys where higher strength or greater strength-to-density ratios are advantageous, and will permit higher operating temperatures in particular applications

Advanced materials research for long-haul aircraft turbine engines

The status of research efforts to apply low to intermediate temperature composite materials and advanced high temperature materials to engine components is reviewed. Emerging materials technologies and their potential benefits to aircraft gas turbines were emphasized. The problems were identified, and the general state of the technology for near term use was assessed

Tungsten fiber-reinforced nickel superalloy with greatly increased strength at 2000 degrees F

Superalloy has 1000-hour strength of 37,000 psi at 2000 degrees F. The strength to density ratio of the composite is also greater, permitting applications where reduced weight rather than greater strength is desired

Tungsten fiber-reinforced copper composites form high strength electrical conductors

Tungsten fiber-reinforced copper composites have tensile strength, yield strength, and modulus of elasticity proportional to fiber content. The composites form high strength electrical conductors

Effect of fiber diameter and matrix alloys on impact-resistant boron/aluminum composites

Efforts to improve the impact resistance of B/Al are reviewed and analyzed. Nonstandard thin-sheet charpy and Izod impact tests and standard full-size Charpy impact tests were conducted on composites containing unidirectional 0.10mm, 0.14mm, and 0.20mm diameter boron fibers in 1100, 2024, 5052, and 6061 Al matrices. Impact failure modes of B/Al are proposed in an attempt to describe the mechanisms involved and to provide insight for maximizing impact resistance. The impact strength of B/Al was significantly increased by proper selection of materials and processing. The use of a ductile matrix and large diameter boron fibers gave the highest impact strengths. This combination resulted in improved energy absorption through matrix shear deformation and multiple fiber breakage

Improved impact-resistant boron-aluminum composites for use as turbine engine fan blades

Efforts to improve the impact resistance of B/Al are reviewed and analyzed. Thin sheet Charpy and Izod impact tests and standard full size Charpy impact tests were conducted on unidirectional and angleply composites containing 4, 5.6 and 8 mil boron in 1100, 2024, 5052 and 6061 Al matrices. Impact failure modes of B/Al are proposed in an attempt to describe the mechanisms involved and to provide insight for maximizing impact resistance. The impact strength of B/Al was significantly increased by proper selection of materials and processing. The use of more ductile matrices (1100 Al) and larger diameter (8 mil) boron fibers gave the highest impact strengths by allowing matrix shear deformation and multiple fiber breakage