Microstructure and strengthening mechanisms in the Al/Al–Cu–Cr–Fe composites consolidated using spark plasma sintering

In this study, Al-based composites reinforced with Al–Cu–Cr–Fe quasicrystal were consolidated using spark plasma sintering (SPS). The microstructural evolution and densification mechanisms in the sintering as well as the strengthening mechanisms of the composites were investigated. Due to their low thermal and electrical conductivity, the temperature of Al–Cu–Cr–Fe particles was kept so low in the sintering process that their icosahedral phase (a thermodynamically unstable phase) and rugged surface were preserved, forming interlocking with the Al matrix. The introduction of Al–Cu–Cr–Fe into Al improved the yield strength from 91.2 ± 2.8 MPa to 298.7 ± 6.4 MPa. The plastic deformation of Al matrix enwraps hard Al–Cu–Cr–Fe particles and accounts for the densification of the composites, generating a high density of dislocations near the interface. These dislocations are a dominant factor for the strength improvement in the composites.