Dislocation interaction with Ω phase in crept Al-Cu-Mg-Ag alloys

The interaction between dislocations and the plate-like Ω phase in crept Al-Cu-Mg-Ag alloys is well investigated by electron microscope technique. Our results shows that Ω phase are sheared by dislocation during creep. Except for the small shearing steps, large steps produced by multiple dislocation shearing along the same slip planes are undoubtedly observed. These shearing steps act as the potential growth ledges and considerably accelerate the thickening of Ω phase during creep. High resolution transmission electron microscopy analysis confirms the interface created by dislocation shearing remains coherent. In addition, the slip system in Ω phase is (010)Ω[001]Ω.