Microstructural and Hardness Investigation of Basalt Fiber-Reinforced Aluminum Matrix Composites Produced by Powder Metallurgy

In this study, basalt fiber-reinforced aluminum matrix composites were successfully produced using the powder metallurgy technique. Aluminum powder with a particle size range of 40–70 µm was used as the matrix material, while basalt fiber was employed as the reinforcement phase. In addition to basalt fiber, Mg, Zn, Si, Cu, and Ti alloying elements were incorporated into the matrix in different compositions to investigate their influence on microstructural evolution and hardness behavior. The powder mixtures were mechanically blended at 12 rpm for 60 min and compacted under a pressure of 20 kg/mm². To minimize oxidation during sintering, the green compacts were sealed in quartz glass tubes and sintered at 675°C for 2 h under an isolated atmosphere. Microhardness measurements and scanning electron microscopy (SEM) analyses were conducted to evaluate the mechanical and microstructural properties of the produced composites. The results demonstrated that basalt fiber addition significantly improved the hardness of the aluminum matrix. The highest hardness value was obtained in the BZL7 sample with an average value of 185.67 HV (2.1%), whereas pure aluminum exhibited an average hardness of 87.67 HV (1.9%). SEM observations revealed the presence of basalt-derived phases and localized porosity within the composite structures. Overall, the developed composites exhibited promising mechanical characteristics for lightweight structural applications.