In this study, the independent and synergic effects of nano-Al2O3 addition and heat
treatment on the microstructure and mechanical properties of Mg-(5.6Ti+3Al) composite
were investigated. The addition of nano-Al2O3 particles to Mg-(5.6Ti+3Al) was carried out in
two ways: (i) direct addition to Mg along with ball milled (Ti+Al) particulates, to form
Mg-(5.6Ti+3Al)-2.5Al2O3 composite and (ii) addition after ball milling together with Ti and
Al, to form Mg-(5.6Ti+3Al+2.5Al2O3) composite. The materials were synthesized through
the disintegrated melt deposition technique followed by hot extrusion, and were
investigated for their microstructure and mechanical properties. Results indicate that the
final microstructure and mechanical properties of Mg composites were greatly influenced by
themode of nano-Al2O3 addition and heat treatment.While the direct addition of nano-Al2O3
particulates caused improvement in fracture strain without affecting the strength properties,
its addition after ball milling resulted in lowering the strength properties without significant
effect on the ductility. The improvement in ductility without affecting the strength values in
the case of Mg-(5.6Ti+3Al)-2.5Al2O3 composite is attributed to the presence of nano-Al2O3
particulates and Al3Ti intermetallics inMgmatrix. The heat treatment of all the composites at
200 °C for 5 h leads to a significant enhancement in ductilitywith slight reductions in strength
values, under both tensile and compressive loading conditions. This is attributed to the stress
relaxation at matrix–reinforcement interface. The best combination of strength and ductility
was obtained after heat treatment of the extruded composites.