High strength bulk tantalum with novel gradient structure within a particle fabricated by spark plasma sintering

High dense tantalum sintering components with a hardness gradient within individual grains were synthesized successfully by means of spark plasma sintering (SPS) of the nitrided tantalum particles at a pressure of 400 MPa and a temperature of 950 °C. High yield strength up to 1350 MPa combined with 12% fracture strain was achieved in the compression tests, which can be attributed to the novel gradient composition inside the grain structure.

► Gradient structured Ta compacts were prepared by using SPS.
► High strength and apparent ductility were obtained.
► Strength increases with increasing nitrogen content.
► Excellent properties are associated with the gradient structure.