Structure of a titanium-alloyed high-tin bronze obtained by the Osprey method

The titanium-alloyed bronzes with enhanced (14.5 and 15.5 wt %) tin content obtained by the Osprey method have been studied by the methods of optical, scanning, and transmission electron microscopy with the use of quantitative microanalysis in the initial state and after hot extrusion. These alloys have been employed as bronze matrices of multifilamentary superconducting Nb/Cu-Sn composites. An increase in the tin content in the bronze matrix makes it possible to enhance the critical current density of the multifilamentary composite owing to the improvement of the structure and composition of a superconducting Nb₃Sn compound that is formed upon diffusion annealing. It has been shown that the Osprey technology allows one to obtain bronzes with an enhanced Sn content and simultaneously to reduce the dendritic segregation characteristic of cast bronzes. The distribution of Sn and Ti in these alloys has been investigated. A more homogeneous structure in the initial state is characteristic of the alloy Cu-14.5Sn-0.24Ti (wt %). The increase in the tin content to 15.5 wt % leads to the formation of microregions of dendritic segregation with an (α + δ) eutectoid in the initial state, which slightly decreases plastic characteristics of this bronze.     

Some properties and microstructure of C-TiC alloys obtained by precipitation from the gaseous phase

Conclusions It has been established that C-TiC alloys prepared by precipitation from the gaseous phase constitute mixtures of titanium carbide and pyrographite. Like pyrographite, they exhibit an anisotropy of properties, the degree of anisotropy decreasing with increasing titanium carbide content of the alloys.Translated from Poroshkovaya Metallurgiya, No. 12 (84), pp. 32–38, December, 1969.     

Deformability of niobium and tin bronze during compression

The deformability of Cu–14.5 wt % Sn–0.25 wt % Ti bronze and pure niobium (99.84%) is studied during compression tests. It is found that an increase in the strain rate or a decrease in the test temperature can improve the strength characteristics of both materials. The strength properties of bronze are more sensitive to a change in the temperature–rate deformation conditions.     

Effect of alloying on the structure of bronze with enhanced tin content

Bronzes with an enhanced (14 wt %) tin content which were alloyed with titanium, zirconium, and boron have been studied in the as-cast, homogenized, and deformed states by scanning and transmission electron microscopy and X-ray diffraction analysis. These alloys are of interest as a matrix material for superconducting Nb/Cu-Sn composites in which the high tin content and the alloying of the bronze matrix make it possible to improve superconducting characteristics at the expense of optimization of the structure and properties of layers of the Nb₃Sn compound formed at the niobium-bronze interface via reactive diffusion. The distribution of alloying elements in different states of the bronze has been investigated. It has been shown that Zr is uniformly distributed in the alloy and forms no coarse inclusions, whereas Ti forms in the as-cast state large platelike precipitates that can adversely affect technological characteristics of the bronze matrix and the composite as a whole.