Characteristics of β -> α phase transformation during continuous cooling in Zircaloy-4 alloy

Abstract

The β -> α phase transformation was studied in continuous cooling processes of the Zircaloy-4 alloy, usually used in the cladding of fuel rods in PWR type nuclear reactors. Regarding this, dilatometry experiments were carried out with variable cooling rate on samples with the same initial microstructure, which showed a behavior dependent on the cooling rate for the expansion associated to transformation. The tested samples were characterized by optical microscopy; a hypothesis based on possible changes in the crystalline texture associated with the transformation is preliminarily proposed to interpret the observed dilatometric behavior.