The compressive creep behavior and deformation sub-structures of binary Mg-Y alloys, containing 0.2 to 2.4mol%Y, were investigated at 550 to 650K under stresses of 4 to 200MPa. It was found that the addition of Y improved the creep strength of Mg more efficiently than did Al or Mn. This efficiency decreased with increasing temperature. The apparent activation energy for creep was substantially greater than that for self-diffusion in Mg. Transmission electron microscopy revealed that the non-basal slip systems were activated at 650K, although the basal slip systems operated mainly at 550K. Both the high activation energy and the cross-slip of dislocations from the basal to the non-basal planes could be consistently explained by the cross-slip mechanism.

Creep Deformation Behavior and Dislocation Sub-Structures of Mg-Y Binary Alloys. M.Suzuki, H.Sato, K.Maruyama, H.Oikawa: Materials Science and Engineering A, 2001, 319-321, 751-5