Development of tantalum-tungsten alloy by powder metallurgy method

To achieve tantalum alloys only casting methods have been used while spark plasma sintering (SPS) and hot press (HP) as the two sintering method are known and very applicable. In this study, two composition of tantalum and Ta-3wt.%W were made using these two methods. Diffusion plays an important role in the production of alloys in powder metallurgy which in practice, sufficient time was provided for the tungsten atoms with annealing process after sintering to attain a proper diffusion depth. Sintering for 60 minutes by HP leads to production of Ta-3wt.%W alloy, while the SPS sample required to be annealed because of the inadequate time to infiltrate and remaining tungsten. The density of the SPS and HP compacted samples reached 90–99.3% of the theoretical value depending on the dwell time. The lattice parameters were measured on the results of X-ray diffraction and the effect of oxygen and tungsten on lattice parameter was evaluated. Also hardness was increased by dissolution of tungsten in tantalum so that by dissolving 3% tungsten, Vickers hardness reached 320.

Keywords:

Tantalum- Tungsten Alloy , Lattice Parameter , Spark Plasma Sintering , Hot press , Powder metallurgy