Abstract:Tungsten was subjected to severe plastic deformation at 440°C using high pressure torsion (HPT) with an improved die-set. Microhardness measurements suggest an appreciable ductility level in tungsten after HPT with Vickers microhardness as high as ~1150 HV. Differential scanning calorimetry (DSC) analyses showed that samples that developed less strain had a higher recrystallisation temperature (greater than 1450°C) than samples that developed more strain (~800°C). X-ray diffraction analyses indicate increases in lattice strain of up to 0.35%, lattice parameter up to 0.3177 nm and dislocation density up to 2.4 × 1015 m-2. The current study introduces the improved HPT process as an effective route for the production of ultrahigh strength W with significant ductility and specified thermostability.