Enhanced mechanical properties and thermo-physical properties of 7075Al hybrid composites reinforced by the mixture of Cr particles and SiCp

The present work reports on a study of improving mechanical properties and thermo-physical properties of a 7075Al hybrid composite (50SiC+5Cr) simultaneously, which was reinforced by a mixture of 50 vol% SiCp and 5 vol% Cr particles. Cr particles were well reserved in the 7075Al hybrid composite following the squeeze casting process. Compared with the 50 vol% SiCp/7075Al composite (50SiC), the ultimate tensile strength (UTS) and elongation (EL) of the 7075Al hybrid composite were increased by similar to 19% and similar to 15%, respectively. Additionally, the 7075Al hybrid composite exhibited higher thermal conductivity and lower thermal expansion than those of 50 vol% SiCp/7075Al and 55 vol% SiCp/7075Al (55SiC). Interestingly, fracture mechanism analyses revealed that the 7075Al hybrid composite showed a mixed morphologic feature of ductile-brittle fracture model while the 50 vol% SiCp/7075Al composite exhibited an evident brittle fracture model. The interface conductance (hc) of the 50SiC+5Cr composite is higher than those of the 50SiC and 55SiC composites. The good interface between Cr particles and the Al matrix and the reduced dislocation density present in the Al matrix are responsible for the excellent mechanical properties and good thermo-physical properties of the 50SiC+5Cr composite. (C) 2017 Elsevier B.V. All rights reserved.