Effects of micro-alloying with Sc and Mn on microstructure and mechanical properties of Al-Mg based alloys

An extensive investigation was made on the effects of micro-alloying with small amounts of Sc and Mn on the microstructure and mechanical properties of the Al-Mg based alloys. It is found that the micro-alloying can significantly enhance the tensile strength of the alloys, and eliminate the dendritic cast structure in it. Many fine, spherical and dispersive AI,Sc particles are found in the annealed Al-Mg-Mn-Sc alloys, which can strongly pin up dislocations and subgrain boundaries, thus strongly retarding the recrystallization of the alloys, The strengthening of the micro-alloyed Al-Mg alloys is attributed to the precipitation strengthening by the AI,Sc particles and to the substructure strengthening.