OS0112 Mg-Y基合金の高温クリープ変形挙動と転位下部組織

抄録

Compressive creep behavior and dislocation substructures in hot-rolled (40%) Mg-Y based alloys have been investigated in this study. Creep strength of magnesium is significantly improved by the simultaneous addition of yttrium and zinc. Apparent activation energy for creep in Mg-Y and Mg-Y-Zn solid solution alloys are around and/or more than 200 kJ/mol at the temperature range from 455 to 700 K. These values are higher than the activation energy for self-diffusion coefficient in magnesium (135 kJ/mop. Many stacking faults, which are planar type defects are observed on the basal planes of the magnesium matrix in Mg-Y-Zn ternary alloys. Transmission electron microscopic observation has been revealed that the non-basal slip of the a-dislocations is activated by these alloys during creep above 480 K. The rate controlling mechanism of Mg-Y based solid solution alloys are considered to the cross-slip controlled dislocation creep.