2011 Volume 52 Issue 5 Pages 1016-1025
The mobility of dislocations has been investigated in WE43 magnesium alloy during recovery and recrystallisation for samples deformed plastically, at different degrees of plastic deformation and temperatures. The dislocation density decreases within the temperature range 550 K–650 K, in good agreement with the characteristic recovery temperature of this alloy, 630 K. New dislocations located at the grain boundaries start their movement from 650 K onwards. During recrystallisation, which has a characteristic temperature of around 700 K, the density of dislocations decreases and the possibility of movement of the dislocations also decreases, due to the development of internal stresses during the growth of new strain-free grains.
The excess of vacancies promoted by the plastic deformation in cold worked samples is consumed up to temperatures of 550 K. New thermal vacancies which assist the movement of grain boundaries and dislocations are created after annealing at temperature above 650 K. Hot worked samples which exhibit dynamic recovery or recrystallisation, depending on the degree of plastic deformation; have a structure with both a scarce dislocations mobility and also a small dislocations density.
