Preparation and Properties of Titanium Obtained by Spark Plasma Sintering of a Ti Powder–Fiber Mixture

Porous titanium is a functional structural material with certain porosity, which is prepared from titanium powder and titanium fiber. In order to study the porosity, phase structure, microstructure, sintering mechanism and mechanical properties of porous titanium obtained by spark plasma sintering of a Ti powder–fiber mixture at different sintering temperatures, a spherical titanium powder (D(50) of 160 μm) was prepared via plasma rotating electrode processing, and titanium fiber (average wire diameter of fiber of 110 μm) was prepared by drawing, and they were mixed as raw materials according to different mass ratios. Porous titanium with a fiber–powder composite porous structure was prepared by spark plasma sintering at sintering temperatures of 800 °C, 900 °C and 1000 °C under a sintering pressure of 20 MPa. The results showed that there were no new phases occurring in porous titanium with porosity of 1.24–24.6% after sintering. Titanium fiber and titanium powder were sintered using powder/powder, powder/fiber and fiber/fiber regimes to form composite pore structures. The mass transfer mechanism of the sintered neck was a diffusion-dominated material migration mechanism during sintering. At higher sintering temperatures, the grain size was larger, and the fiber (800 °C; 10–20 μm) was finer than the powder (800 °C; 10–92 μm). The stress–strain curve of porous titanium showed no obvious yield point, and the compressive strength was higher at higher sintering temperatures. The results of this paper can provide data reference for the preparation of porous titanium obtained by spark plasma sintering of a Ti powder–fiber mixture.