Thermal fatigue damage of Cu-Cr-Zr alloys

The primary aim of this investigation is to examine thermal fatigue damage (TFD) in Cu-Cr-Zr alloys used in High Heat Flux components of Tokamak and its subsystems. Thermal fatigue experiments have been carried out between 290 degrees C and 30 degrees C, which is analogous to the condition of service application on two Cu-Cr-Zr alloys having different aging treatments. The extents of TFD have been examined by standard measurements of electrical conductivity, lattice strain, residual stress and dynamic elastic modulus, supplemented by characterizations of microstructure and determination of hardness and tensile properties. The results lead to infer that the relative amounts of damage are different in the two alloys which are further dependent on their aging conditions: the reasons for the observed difference have been explained. The operative mechanisms of TFD are revealed to be as formation and subsequent coalescence of microvolds, and/or initiation and growth of microcracks. (C) 2013 Elsevier B.V. All rights reserved.