Strain Enhanced Precipitate Coarsening during Creep of a Commercial Magnesium Alloy AZ80

Growth of precipitates during creep was investigated of a commercial magnesium alloy AZ80. TEM observations in this study confirmed that the cube of the average particle size changed roughly with creep time at grip parts and the growth rate was greater at the gauge part than at the grip part of crept specimens. The cube of the average particle size changed roughly with creep time at grip parts. This suggests that the coarsening of particles at grip part obeyed the Ostwald ripening theory in which the growth rate was assumed to be controlled by the lattice diffusion. In order to make clear the factors affecting the growth rate of precipitates at gauge part, interrupted creep tests were carried out. The present analysis of the experimental results showed that the effect of strain on the particle growth was more important than that of stress. The influence of concurrent straining on the particle growth is also discussed in terms of traveling dislocations with solute atmospheres.