The influence of Si and Mg rich phases on the mechanical properties of 6061 Al-matrix composites reinforced with Al2O3

• Published in: Journal of materials science 2002-04, Vol.37 (8), p.1497-1502
• Main Authors: GOMEZ DE SALAZAR, J. M, BARRENA, M. I
• Format: Article
• Language: English
• Subjects: Aging (metallurgy); Aluminum base alloys; Aluminum matrix composites; Aluminum oxide; Applied sciences; Depletion; Dislocations; Dispersion hardening metals; Exact sciences and technology; Heat treatment; Magnesium compounds; Materials science; Mechanical properties; Metal matrix composites; Metal silicides; Metals. Metallurgy; Morphology; Phases; Powder metallurgy. Composite materials; Precipitates; Production techniques; Silicon
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1023/A:1014967324577

Besides altering the kinetics of precipitation, the reinforcements with alumina particles appear to alter the relative proportions of the various phases formed in the matrix alloy during ageing. Alumina also seems to reduce the volume fractions of hardening phase in these materials, especially at higher contents. One reason for this effect could be the dislocation relief of the matrix strain associated with the early precipitates. Additionally, the diffusion of Mg and its subsequent incorporation into the reinforcement at the Al2O3/Al interface could also result in Mg depletion from the matrix, accounting for the reduction of the β (Mg2Si) particle sizes. Magnesium incorporation into interfacial alumina to form MgAl2O4 has been observed in these materials. This paper shows that the nature and morphology of the second phases depend the heat treatment conditions on.