M. Li, S. Zhou, W. Wang, F. Liu, H. Li, Y. Qin, Z. Zhang, Y. Wu
April 29, 2020
In this work, the effect of friction stir processing (FSP) on microstructure and mechanical properties of an Al-5Mg-0.2Sc-0.1Zr alloy was investigated in detail. The results showed that the as-cast alloy exhibited equiaxed grain structure with a large number of primary Al 3 (Sc,Zr) particles inside. FSP imposed a significant grain-refining effect on the alloy, changing the average grain size of 50.5 μm to 2.4 μm, which is attributed to the occurrence of dynamic recrystallization and generation of nanoscaled Al 3 (Sc,Zr) precipitates. These Al 3 (Sc,Zr) dispersoids intense impeded the movement of dislocation and grain boundaries and hindered the growth of recrystallized grains, resulting in a remarkable grain-refining strengthening, substructure strengthening and precipitation strengthening effect. On the other hand, the residual primary Al 3 (Sc,Zr) particles gave rise to a loss in ductility.