Fabrication and properties of in-situ Al/AlB2 composite reinforced with high aspect ratio borides

Production and properties of metal matrix composites reinforced with an in-situ high aspect ratio AlB2 flake have been investigated. Boron 2.2wt.% was dissolved in pure Al and Al-Cu alloy at 1300°C by adding directly boron oxide which resulted in 4 vol.% reinforcing phase. The in-situ AlB₂ flake concentration was increased up to 30 vol.% in order to increase the tensile strength of the composites. Hardness, compressive strength and tensile strength of the composite were measured and compared with their matrix. Results showed that 30 vol.% A1B₂/Al composite show a 193% increase in the compressive strength and a 322% increase in compressive yield strength. Results also showed that ductility of composites decreases with adding AlB2 reinforcements.