Phase transformations in metastable beta Zr12Nb alloy studied by in-situ synchrotron X-ray diffraction considering well known metastable beta titanium alloys
Abstract
Zirconium alloys with only very low amount of alloying elements have been studied for application in nuclear industry. As zirconium and titanium are in the same group of periodic table of elements and undergo the same phase transformations, a deep understanding of titanium alloys was used for studying phase transformations in metastable beta zirconium alloy Zr12Nb.
For in-situ observations of phase transformations during heating, high energy synchrotron X-ray diffraction was used. In order to observe phase composition directly, ex-situ SEM and TEM observations were performed. At room temperature, β matrix with nanometer-scale ω phase particles were observed in quenched alloy. During linear heating, above 400°C, the ω particles grow and stabilize while the surrounding β matrix changes its composition. At 560°C, ω phase dissolves suddenly and α phase starts to grow. As ω phase particles are larger and phenomena associated with them are more pronounced in zirconium alloys compared to titanium alloys, some effects occuring in both titanium alloys can also be explained by studying zirconium alloys.