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Titanium and its alloys can be used successfully as matrix material for continuous filaments, such as boron or silicon carbide. The single limiting factor in fabrication and life of the composites is the interaction between filament and matrix. Several attempts have been made to manufacture filament-reinforced titanium alloys; however, methods such as powder metallurgy, creep controlled diffusion bonding, and plasma arc spraying have been unsuccessful because interaction has led to reaction layers in excess of 1 micron in thickness. Compound thicknesses of such magnitudes render composites useless because cracks form in the compound at low strains and cause subsequent failure of the filaments. Recent developments in manufacturing techniques have made it possible to control formation of boride or sili-cide so that prolonged life is obtained. This paper describes properties of such composites.

Research on metal-matrix composites for turbine compressors has demonstrated that four areas of compatibility are very important in composite design, and all must be considered in detail when specifying metal-matrix composites for structural applications. These areas comprise: chemical compatibility between matrix and filament, elastic strain compatibility, physical property compatibility, and manufacturing process compatibility. The designer must have detailed knowledge of every step in the composite manufacturing process to predict structural performance. Control of the manufacturing process to achieve maximum reinforcement from the filaments is considered the most important single factor. Asymmetrical elastic properties introduced by residual stresses or area ratio variation appear to be the most difficult aspect to appraise. A result of such asymmetry is dimensional and structural instability in a changing temperature environment.

Practical uses of beryllium assemblies in meeting current critical aerospace and nuclear requirements are discussed. Emphasis is placed upon braze joining structural components and effective manufacturing methods. Recent technological advancements in metallurgical bonding of beryllium make possible fabrications heretofore not considered as feasible. Brazing, braze welding, and fusion welding of beryllium to itself and to dissimilar metals is evaluated by reference to specific applications. Brazing receives prime consideration as it is the most versatile and widely used metallurgical joining process.

New developments in braze-joining are presented. This technology will extend practical utilization of beryllium in fabrication of lightweight, exceptionally stiff components. Consideration of structural beryllium brazements is discussed. Some examples are monocoque cylindrical and conical shapes, radiator assemblies, sheet metal brackets, and sandwich structures. Beryllium exhibits attractive properties up to 1200 F. Special fabrication techniques are necessary, however, due to its metallurgical and mechanical peculiarities. Data presented show the effect of filler metal interactions on stress levels attainable in properly brazed joints. Beryllium is extremely versatile and is an unparalleled material of construction where strength/weight at elevated temperature is the criterion.