Abstract
An investigation of the properties of titanium-tin and titanium-tin-aluminium alloys, produced by powder metallurgy, has been carried out, using as the starting material titanium produced by the reduction of titanium tetrachloride with sodium. Specimens of unalloyed titanium with low porosities could be obtained after a single pressing and sintering operation and the mechanical properties of these specimens were comparable to those of arc-melted material. The addition of tin had a beneficial effect upon the compacting and sintering characteristics of the powder, as well as markedly affecting the mechanical properties. The preparation of titanium-tin-aluminium alloys was more difficult and, for satisfactory results, compacts had to be worked after sintering. By this means specimens with relatively low alloying additions could be prepared to give acceptable mechanical properties. When, however, the alloying contest exceeded a certain level, the compacts were exceptionally brittle. This is believed to be due to inherent brittleness associated with the composition and not to be due to the method of preparation. It is concluded that sodium-reduced titanium is a suitable starting material for the satisfactory fabrication of certain titanium alloys by powder metallurgy and that the use of these methods offers certain advantages over production by arc-melting. Further incidental investigations, during the progress of the work, were carried out into the wetting of titanium by molten tin, the structure of titanium after cooling at different rates and the constitution of certain titanium-tin-aluminium alloys.