Study of the thermoelectric power evolution of Zr-based alloys with Nb additions

The thermoelectric power (TEP) evolution of zirconium alloys was investigated by varying the niobium content from 0.1 to 0.8 at.%. The phase-transformation temperature and the recrystallization behavior of the alloys were characterized by the TEP evolution from 550 to 940 °C, which showed that the α to β phase-transformation temperature decreased as the Nb content increased. The phase transformation occurred in the temperature range 910–940 °C for the 0.2 at.% Nb addition while the transformation occurred below 850 °C for the 0.8 at.% Nb addition. For the 0.2 at.% Nb addition, the aging time required for the completion of recrystallization was about 60 min in the temperature range of 575–600 °C and about 10 min in the range of 625–650 °C. However, as the Nb addition increased to 0.5 at.%, the required aging time for the recrystallization turned out to be longer than the 0.2 at.% Nb addition. In addition, an equation for the solution limit of niobium for the present specimens was established from the experimental results and microstructural characteristics of TEP were discussed.