Controlling factors of the ductility in Al-Mg alloys

Abstract

Influence of Mg content, grain size, 0.2% proof stress, and alloying elements (such as Zn, Mn, Cu, Y) on the ductility of Al-Mg alloys have been investigated, and controlling factors have been revealed. The uniform elongation is expressed by ε_u=n(1-σ_o/σ_i) where n is the strain hardening exponent, σ_i the true ultimate tensile strength, σ_o the 0.2% proof stress, and ε_u the uniform elongation. The strain hardening exponent n increases as the Mg content increases, which depends on the increasing difficulties of the cross slip of dislocations. The 0.2% proof stress σ_o decreases as the grain size increases, which increases the uniform elongation ε_u.