Microstructure and Mechanical Properties of Ultrafine Structured Al-4wt%Cu-(2.5-10) vol.%SiC Nanocomposites Produced by Powder Consolidation Using Powder Compact Extrusion

Abstract

Ultrafine structured Al-4wt. %Cu- (2.5-10) vol. % SiC nanocomposites were produced by high energy mechanical milling of a mixture of Al and Cu powders and SiC nano-powder to produce nanocomposites powders, followed by consolidation of the powders using powder compact extrusion (PCE). Scanning and transmission electron microscopy as well as tensile testing were used to characterize the extruded nanocomposite bars. Increasing the volume fraction of SiC nanoparticles from 2.5 to 5.0 causes the yield strength, ultimate tensile strength and microhardness of the nanocomposite to increase from 98 MPa, 168 MPa and 104 HV to 391 MPa, 400 MPa and 153 HV, showing the effectiveness of SiC nanoparticles and microstructural refinement in strengthening the material. However, the ductility decreases from 6.8% to 2%, possibly due to the existence of SiC nanoparticle agglomerates in the Al-4wt%Cu-5vol.%SiC nanocomposite. The ultrafine structured Al-4wt%Cu-(7.5 and 10)vol.%SiC nanocomposite bars fractured prematurely during tensile testing. The possible reason for this may be the existence of SiC nanoparticles agglomerates in their microstructure.