INVESTIGATION OF MICROSTRUCTURE AND HARDNESS PROPERTIES OF AGED AA 7075 MATRIX B4C / SiC REINFORCED COMPOSITE-HYBRID MATERIALS

Aluminum hybrid composites are next-generation metal matrix composites having the potential for advanced and new engineering applications. Therefore, in the study, using the powder metallurgy method, microstructure and hardness properties of aluminum (AA7075) composite and hybrid materials were examined in the combination of different ceramic reinforcement phases (5-10-15% B 4 C and SiC). Pressed (700MPa) matrix/reinforcement powder mixtures were 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 to determine the microstructure and hardness properties of the test samples, optical microscope, scanning electron microscope (SEM), and micro-hardness (HV0.1) measurements were made respectively. At the same time, micro-hardness values were examined by applying the solution-quenching to the test samples at 475 °C temperature for 2 hours and the aging heat treatment at 120 °C temperature for 24 hours. Compared to single ceramic phase composite materials, a decrease in density and hardness value occurred in 5% B 4 C-SiC reinforced aluminum hybrid composite materials. Furthermore, it was determined that the micro-hardness values of test samples increased after the aging heat treatment.