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Isothermal metal working (ISR) using resistance heating of the metal being worked is a new process developed by the Solar Division of International Harvester. The process is unique and can be used effectively to roll structural as well as special shapes from various alloys including titanium, stainless steel, and superalloys. Sheet or plate stock can be rolled into Z-section stiffeners and channels with square external corners and internal fillets. Bar stock can be rolled into “I” and “T” sections in one-or two-roll passes. Airfoils for gas turbine blades and vanes can be formed with rolls profiled with the contour shapes desired. The general characteristics of the processes are described. These include: high metal recovery (better than 90%); fine surface finish (16 rms); freedom from surface contamination; major thickness reductions per pass (better than 80%); control of microstructure; and very low energy consumption in processing.

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.