Characterization and mechanical properties of α-Al 2 O 3 particle reinforced aluminium matrix composites, synthesized via uniball magneto-milling and uniaxial hot pressing
- Citation data:
Advanced Powder Technology, ISSN: 0921-8831, Vol: 28, Issue: 3, Page: 1054-1064
- Publication Year:
- Chemical Engineering; Engineering; via; uniball; magneto-milling; uniaxial; hot; characterization; pressing; mechanical; properties; α-al2o3; particle; reinforced; aluminium; matrix; composites; synthesized; Science and Technology Studies
Al-based composite powders containing 2, 4, 7 and 10 volume fraction of α-Al 2 O 3 were prepared using the uniball controlled magneto-milling method and were then uniaxially hot pressed at (600 ± 10)°C under 70 MPa for 15 min. The resulting composites were greater than 99% theoretical density with enhanced mechanical properties. Detailed characterization was performed using: X-ray diffraction, scanning electron microscopy equipped with energy dispersive spectroscopy, electrical conductivity, compression, ultra-micro indentation testing and pin on drum wear testing at ambient temperature. Microstructure-mechanical property correlations were obtained as functions of α-Al 2 O 3 volume fraction. It was found that controlled milling resulted in an uniform distribution of the hard α-Al 2 O 3 particles within the Al, an acceleration of Al hardening and fracturing, and strain accumulation by the Al matrix. Hardness, strength, wear resistance and electrical resistivity of the monolithic products increased with increasing the volume fraction of α-Al 2 O 3 up to 10 vol.%. These were: HV = (1.84 ± 0.26) GPa, maximum compressive strength = (845 ± 33) MPa, compressive yield strength = (515 ± 11) MPa. Outcomes were interpreted in light of the structural defects induced by milling, the presence of α-Al 2 O 3, and dispersion of iron milling contaminants, with additional effects caused by oxygen introduced during the milling and/or the heat treatment.