Mechanically milled AA6061/(Ti3Al)P MMC reinforced with intermetallics – the structure and properties

The present work investigates the production of aluminium AA6061 matrix composite materials reinforced with Ti3Al particles by powder metallurgy techniques and hot extrusion. The milling process has a big influence on the characteristics of powder materials, changing the spherical morphology of as-received powder during milling process to flattened one due to particle deformation followed by welding and fracturing particles of deformed and hardened enough which allows to receive equiaxial particles morphology again. The investigation shows that so called brittle intermetallic particles yields to plastic deformation as good as ductile aluminium alloy particles. That indicates that in contrary to ceramics particle, the Ti3Al intermetallic powder cannot play a role of the accelerator during mechanical milling. The mechanically milled and extruded composites show finer and better distribution of reinforcement particles what leads to better mechanical properties of obtained products. The hardness increases twice in case of mechanically milled and only 20–25 HV1 for low energy mixed and hot extruded composites. The finer microstructure increase mechanical properties of composites materials. The higher reinforcement content results in higher particles dispersion hardening. Composites reinforced with 15% of Ti3Al reach about 400 MPa UTS.