COMPOSTI A BASE DI TITANIO RINFORZATI DA FIBRE DI CARBURO DI SILICIO AVENTI MIGLIORATE PROPRIETA' DI TRAZIONE

摘要

A method of altering the crystal form of an alloy is disclosed. To accomplish this change in crystal form, the concentrations of the more volatile constituents of the alloy are reduced and the concentration of the less volatile constituents is increased on a relative basis. The process may be carried out in forming a reinforced structure. For this purpose, an improved reinforced matrix and a method of forming it are taught. The reinforcement may be silicon carbide filaments or other reinforcing filaments. The matrix is a titanium 1421 alloy nominally containing 14 weight percent of aluminum and 21 weight percent of niobium. The matrix is formed by plasma-spray forming a powder of the alloy to impart to the alloy particles a superheat during the plasma-spraying as the particles traverse the plasma plume. As a result of the superheat, the alloy is changed in its composition to reduce the aluminum concentration and to increase the niobium and titanium concentrations on a relative basis. As a result of the change in composition the crystal form of the spray deposited matrix is altered to increase the amount of the beta-phase crystal form of the alloy which is present and to decrease the amount of the alpha-2 crystal form of the alloy which is present. The result is the formation of a matrix which is less subject to cracking and which has greater strength.