Influence of Nb content on the microstructure and deuterium retention of W-Nb alloys

W-Nb alloys were prepared using machine milling and spark plasma sintering. Field-emission scanning electron microscopy, high-resolution transmission electron microscopy were used to characterize the samples. Thermal desorption spectroscopy was used to measure the deuterium retention. Results indicated that the interdiffusion between W and Nb occurred during high temperature sintering and formed Nb(W) solid solution. The grain size decreased with Nb content increased, and porosity of W-Nb alloys was decreased significantly compared to W bulk. Hence, Nb alloy had a significant effect on promoting W-based material densification. The microhardness increased as Nb content increased, which was ascribed to fine grain and low porosity. D retention in W-Nb alloys was higher than that in pure W (D-2(+) flux similar to 10(21) m(-2) s(-1), ion energy similar to 5 KeV). Total D retention increased as Nb content increased, which was ascribed to the density of grain boundaries that increased as Nb content increased and higher affinity between Nb and D.