Influences of strontium addition and whisker content on solidification behavior of SiCw/Al-18Si metal matrix composites

Solidification behavior of SiC(w)/Al-18Si metal matrix composites (MMCs) was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimeter (DSC) in order to reveal the effects of strontium addition and whisker content. The results show that the Si phase does not nucleate on SiC whisker surface. With the increasing of SiC whisker content, solidification onset and peak temperatures of primary Si decrease. Sr addition lowers solidification onset and peak temperatures of primary Si, and reduces its size. Whisker content has larger effects on solidification onset and peak temperatures of primary Si without Sr addition than that of primary Si with Sr addition. But solidification onset and peak temperatures of eutectic are barely affected by whisker content and Sr addition.