Formability of AA6061/SiC(p) composite at elevated temperatures

Abstract

High temperature deformation behaviour of composites consisting of an AA6061 matrix reinforced with 15 vol.% of SiC particles, 1 or 8 μm in diameter, and the matrix alloy has been investigated. Uniaxial compression tests were carried out at temperatures from 593 to 873 K and strain rates from 2,78x10(-4) to 2,78x10(-3)s(-1). The modified Ludwigson analysis in the form σ = Kε(v) ± Δ has been employed to describe the high temperature strain hardening of these composites and the matrix alloy. Based on the results of investigation the influence of the reinforcing particle diameter, temperature and strain rate on the values of flow stress was determined. The strain hardening are compared with estimates of the theoretical strength of 6061 aluminium alloy. The co-operation of the deformation and precipitation strengthening mechanisms with structural recovery, mainly dynamic recovery and recrystallization process has been also analysed. Microstructural observations of surface relieves have been also conducted to correlate the mechanical characteristics with structure evolution.