Effect of Addition of Cerium Oxide, Cryolite, and Zirconium on Microstructure and Mechanical Properties of In Situ Al-5 wt.% TiB2 Composite Fabricated by Stir Casting.

In this study, in situ titanium diboride particles were synthesized using boron oxide and titanium oxide to reinforce Al 5083 alloy. Stir casting was used to fabricate this composite. The reinforcement particles were formed in situ inside the melt. The working temperature selected for melting and casting was 80 °C. The effect of cerium oxide, cerium oxide + cryolite, and cerium oxide + cryolite + zirconium additives on the composite was investigated. The results showed that cerium oxide decreased the agglomeration of reinforcing particles in the melt. Cryolite prevented melt oxidation, increased melt flow, and improved the distribution of reinforcing particles in the composite. Zirconium caused the refinement of the structure, decreased the agglomeration of TiB₂ particles, and increased the tensile strength of the composite. In addition, the dominant fracture mode in samples modified by cryolite + Zr. CeO₂ + cryolite + Zr caused ductile fracture, while in samples modified by CeO₂ and CeO₂ + cryolite, the brittle fracture was ruling. [ABSTRACT FROM AUTHOR]