Mechanical properties of tungsten in the transition temperature range

In this work, fracture properties of two different powder-metallurgy (PM) tungsten materials have been studied. Two sets of mini bend bar specimens were fabricated either from a cross-rolled tungsten plate (prepared by a conventional PM fabrication route) and from a HIPed tungsten plate (prepared by Powder Injection Molding). Different specimen surface conditions were applied in order to investigate the effect of surface roughness on the bending properties of tungsten. In order to determine transition from ductile to brittle regime, three-point bending tests were performed in the temperature range of 25-300 °C. While the flexure strength (regardless of surface finishing) at room temperature (RT) for the rolled tungsten is significantly higher than that for the HIPed tungsten, the transition from brittle to ductile fracture was found to be rather similar, in the range of 180-230 °C, for both studied materials.