Recrystallization temperature of tungsten with different deformation degrees

Pure tungsten (PW) and W-1 wt% La2O3 (WL10) were prepared by powder metallurgical route followed by the swaging + rolling process. The logarithmic strains are 0, 0.37, 0.58, and 0.98 for WL10 and 0, 0.58 for PW. Heat treatments were performed at temperatures varied from 1,573 to 2,173 K to determine the recrystallization temperature. Recrystallization temperatures are 1,973 and 2,173 K for WL1 (logarithmic strain of 0.37) and WL3 (logarithmic strain of 0.98), respectively. But in the case of WL2 (logarithmic strain of 0.58), full recrystallization is not achieved at temperature of above 2,173 K. Furthermore, the recrystallization temperature of PW with logarithmic strain of 0.58 is at least 300 K lower than that of the equivalent WL10 sample. Moreover, the increase of recrystallization temperature inhibits the strength degradation of WL2: samples lose 4 % and 22 % strength when annealed at 1,573 and 1,973 K compared with room temperature (RT) sample. Finally, the texture evolution for the swaged + rolled WL10 is significantly related to the deformation degree: the dominated orientation is 〈001〉 for WL2 while 〈110〉 for WL3.