In the present work, we have investigated the strain-induced melt activation (SIMA) process in Al-8%Si and Al-25%Si alloys. Primary dendrites were transformed into spherical microstrctures by mushy zone heat treatments of the cold-worked alloys., Various processing parameters which govern the sphering of the dendrites have been examined. The result showed that semi-solid alloys having a typically nondendritic spherical microstructure can be easily produced by this method.