Investigation of the Microstructure of Porous Tube-Shaped Elements Made of Ti-Powder Materials

Abstract

The method of powder metallurgy for the manufacture of titanium products has the advantages of low cost of raw titanium, short technological process, low energy consumption, and less equipment investments. This allows to significantly reduce the total costs. The method is a potential technology to manufacture inexpensive products from titanium alloys. Due to its high strength, low specific weight and high corrosion resistance, titanium is widely used in aerospace and automotive industries and biomedicine. Among various applications of titanium, tube- and disc-shaped products from titanium powder are essential. The paper presents the results on the investigation of products made of titanium powder by the method of magneto-pulse pressing. Titanium powders with a particle size of 160-1000 mm produced by grinding titanium sponge and its powder compositions were used in the investigation. Investigation results on microstructure and porosity are also discussed. The mean porosity of the samples after sintering was 25-28% for products of 4-6 mm thick. With increasing thickness, the porosity increases to 35% and more, while it was non-uniform both over the cross-section of a tube-shaped product and along its length. The outer surface of the product was found to have a looser microstructure. This can be explained by the application of an intermediate fusible layer to the inner wall of the shell, which makes easier the removal of the shall after pressing. The studies generally confirm the possibility tof using the magneto-pulse pressing of titanium powders in shells to manufacturesmall product batches.