Investigation of microstructure and hardness properties of aged AA 7075 matrix B4 C/SiC reinforced composite-hybrid materials

Abstract

Aluminum hybrid composites are next-generation metal matrix compositeshaving the potential for advanced and new engineering applications. Therefore,in the study, using the powder metallurgy method, microstructure and hardnessproperties of aluminum (AA7075) composite and hybrid materials wereexamined in the combination of different ceramic reinforcement phases (5-10-15% B4C and SiC). Pressed (700MPa) matrix/reinforcement powder mixtureswere sintered for 1 hour at a temperature of 560 °C. After the sintering process,density measurements of the test samples were carried out. In order todetermine the microstructure and hardness properties of the test samples, opticalmicroscope, scanning electron microscope (SEM), and micro-hardness (HV0.1)measurements were made respectively. At the same time, micro-hardness valueswere examined by applying the solution-quenching to the test samples at 475 °Ctemperature for 2 hours and the aging heat treatment at 120 °C temperature for24 hours. Compared to single ceramic phase composite materials, a decrease indensity and hardness value occurred in 5% B4C-SiC reinforced aluminum hybridcomposite materials. Furthermore, it was determined that the micro-hardnessvalues of test samples increased after the aging heat treatment.