Dislocation multiplication and dynamics in an aluminium alloy

ABSTRACT A mechanism of dislocation multiplication is introduced. The surface of the Al20Cu2Mn3 phase in an Al alloy can act as a barrier to impede dislocation movement. When two dislocations with opposite Burgers vectors approach each other, dislocations can annihilate if the pair remains at a distance less than the critical distance for annihilation. A dislocation loop is then formed around the Al20Cu2Mn3 phase or dislocations interact with the loop forming a dislocation tangle, which can promote dislocation multiplication. The driving force for dislocation reproduction, the dislocation glide velocity and the rate of dislocation multiplication are discussed.