Effects of zirconium element on the microstructure and deuterium retention of W–Zr/Sc 2 O 3 composites

Dense W and W–Zr composites reinforced with Sc 2 O 3 particles were produced through powder metallurgy and subsequent spark plasma sintering (SPS) at 1700 °C and 58 MPa. Results showed that the W–1vol.%Zr/2vol.%Sc 2 O 3 composites exhibited optimal performance with the best relative density of up to 98.93% and high Vickers microhardness of approximately 583 Hv. The thermal conductivity of W–Zr/Sc 2 O 3 composites decreased initially and then increased as the Zr content increased. The moderate Zr alloying element could combine well with Sc 2 O 3 particles and W grains and form a solid solution. However, excess Zr element leads to agglomeration in the grain boundaries. W–1vol.%Zr/2vol.%Sc 2 O 3 composite had a good deuterium irradiation resistance very closing to pure tungsten compared with the other Zr element contents of composites. Under 500 K, D 2 retention and release of them were similar to those of commercial tungsten, even lower between 400 K to 450 K. Pre-irradiation with 5 keV-He + ions to a fluence of 1 × 10 21 He + /m 2 resulted in an increase in deuterium retention (deuterium was implanted after He + irradiation), thereby shifting the desorption peak to a high temperature from 550 K to 650 K for the W–1vol.%Zr/2vol.%Sc 2 O 3 composite.