The effect of electrospinning time on the structure and mechanical properties of TiO2 continuous nanofibers reinforced aluminum matrix composites

This study was conducted to fabricate aluminum (Al) matrix composites reinforced with titanium oxide (TiO2) continuous nanofibers to study their mechanical properties. For this aim, the solution containing polyvinyl acetate, dimethylacetamide, acetic acid, and titanium isopropoxide was electrospun over an Al layer at different times of 1, 3, 5, 10, and 20 min. After heat treatment at 500 degrees C, sheets containing nanofibers were sintered and connected together by the hot pressing at 625 degrees C. The characterizing of the nanofibers and composites was performed using Transmission electron microscope (TEM), Atomic force microscope (AFM), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) equipped with Energy-dispersive X-ray spectroscopy (EDS) analysis to evident the TiO2 nanofibers morphology and their distribution in the Al matrix. The mechanical properties of composites produced with different electrospinning times were studied. The results showed that maximum yield and tensile strength (about 98% and 62% increase compared to Al matrix, respectively) and toughness were obtained in the composites with electrospinning times of 3 and 5 min. Additionally, it was found that the composites hardness was continuously increased by increasing the time of electrospinning (almost 44% more than the Al matrix). However, the tensile and toughness values were decreased in the composites with more increasing the amount of TiO2 nanofibers at electrospinning times of about 10 min and 20 min. Fracture surface results showed that the presence of large aggregates, breakage of TiO2 nanofibers, and weak bonding between the Al sheets were the effective factors in the decrease of mechanical properties of these composites at more electrospinning times.