Strain-rate cycling tests were carried out, during Blaha-effect measurements at 77 to 254K, on monocrystalline material which was doped with Mg2+, Ca2+, Sr2+ or Ba2+ which acted as weak obstacles. It was found that the critical temperature, at which the effective stress was zero, increased as the divalent ionic size approached that of the K+ ion. The activation energy for interaction between a dislocation and divalent ion-vacancy dipoles was also determined, and was found to increase with divalent ionic size. This was attributed to differences in tetragonality around the dipole.

Y.Kohzuki, T.Ohgaku, N.Takeuchi: Journal of Materials Science, 1995, 30[1], 101-4