HIGH-TEMPERATURE CREEP-BEHAVIOR AND SUBSTRUCTURE IN KCL-KBR SOLID-SOLUTION ALLOYS

The creep behavior and dislocation substructure of pure KCl, pure KBr and two KCl-KBr solid solution alloys was investigated at 700-degrees- C. The reduced primary stage compared to that for the pure materials, stress exponent close to 3, nature of the creep transient after a stre ss reduction for the KCl-KBr alloys is in good agreement with creep be havior observed in class I metallic, KCl-NaCl and KCl-RbCl solid solut ion alloys, where the creep rate is controlled by a viscous dislocatio n glide process. The creep behavior of the KCl-KBr solid solution allo ys is in agreement with the prediction of the glide-climb criterion fo r solid solution alloys developed by Mohamed and Langdon. The dislocat ion substructure of the KCl-KBr solid solution alloys consisted of wel l-developed subgrains whose size was larger than that for the pure mat erials at an equivalent value of normalized stress and varied inversel y with applied stress.