Preparation of in-situ TiB2 and Mg2Si hybrid particulates reinforced Al-matrix composites.

The in-situ (TiB 2 +Mg 2 Si)/Al composite is successfully fabricated by the combination of salt-metal reaction route and ingot metallurgy. The presence of Mg 2 Si phase solves the problem that the particulate volume fraction of TiB 2 /Al composite processed by salt-metal reaction route is low. X-ray diffraction confirms the formation of TiB 2 and Mg 2 Si phases, no other intermediate phases are traced. TiB 2 and Mg 2 Si particles are relative uniformly distributed in the matrix. TiB 2 particles are sub-micron in size, and Mg 2 Si phase is refined from Chinese script morphology to short dispersed sticks by TiB 2 particles. The refined Mg 2 Si phase are under 10 μm in size and the whole reinforcements volume fraction is about 14∼15%. The grains are effectively refined. The mechanism of mutual refinement between TiB 2 particles and Mg 2 Si phase is discussed. The yield stress and ultimate tensile strength of TiB 2 +Mg 2 Si/Al composite are improved by 244% and 229% compared with Al matrix, respectively. [ABSTRACT FROM AUTHOR]