Electro dislocation multiplication and strain effect in 2091 Al-Li alloy

Electro dislocation multiplication and strain effect were investigated. TEM observation showed that when statically held for 15 min, the microstructure of dislocation cell in the specimens without current pulse turned to subgrains with few dislocations in cold rolled state, but when current pulse charged, there were a lot of dislocations although a more rapid recrystallization occurred concurrently; when deformed, the interior dislocations in the specimens without current pulse were annihilated due to dynamic recrystallization, but were not decreased in the current pulse charged specimens in dynamic recrystallization, instead increased. It is indicated that “electron wind” force created by current pulse produced a shear stress for dislocation slip, and caused a dislocation multiplication in static holding of 2091 Al Li alloy; when strain exerted, an additional shear stress was provided to increase the effect of current pulse on dislocation multiplication.