Effect of in-situ TiB2 particles on microstructure and mechanical properties of Mg2Si/Al composites

Abstract

This study intends to offer a depth understanding on controlling the morphology of eutectic Mg2Si by adding in-situ TiB2 particles into 10 wt% Mg2Si/Al composite. The evolution of the microstructure and mechanical properties of Mg2Si/Al composites with different TiB2 particles addition from 1 wt% to 5 wt% is investigated and the mechanism is also discussed. The results show that coarse eutectic Mg2Si phase can be refined and modified with the addition of TiB2 particles, and the lattice coherence between them is also confirmed. Besides, the addition of TiB2 particles can greatly enhance multiple mechanical properties of composites at the same time. With 5% TiB2 particles addition, the modulus, yield strength and elongation of composites are improved 11%, 59% and 141% respectively compared with Mg2Si/Al composites. Moreover, different addition of TiB2 particles changes gradually the fracture behavior of composites from brittle fracture to quasi-cleavage fracture, and finally to entirely ductile behavior.