Spark plasma sintering and mechanical properties of zirconium micro-alloyed tungsten

Dense pure tungsten and W–(0.1, 0.2, 0.5, 1.0) wt% Zr alloys were fabricated through spark plasma sintering method. The relative density of all the samples was about 97%. The FESEM and TEM analysis, tensile tests and Vickers micro-hardness measurements were exploited to characterize these samples. It is found that Zr could capture impurity oxygen in tungsten and form nanometer scaled ZrO2 particles. With the increase of Zr addition from 0 to 0.2 wt%, the room-temperature fracture strength increased from 154 MPa to 265 MPa, and the fracture energy density elevated from 3.73 × 104 J/m3 to 9.22 × 104 J/m3. However, more Zr addition would increase the size of Zr–O particles and significantly decrease the fracture strength and toughness of tungsten.