Enhanced Performance of Mg (AZ91) Composites with Nano B4C: A Comprehensive Study of Microstructure, Mechanical Properties, Acoustic Emission and Thermogravimetric Analysis

The electromagnetic frequency high-energy stir casting process was used to create the high-quality magnesium (Mg) dispersed with varied percentages of nano-sized B₄C (0, 0.5, 1 and 1.5 wt%). The shape and distribution of Mg with nano B₄C were validated by characterization research on nanocomposites utilizing energy-dispersive spectrum, scanning electron microscope and X-ray diffraction. Thermal and mechanical characteristics such as thermogravimetric analysis/differential thermal analysis and tensile strength were explored utilizing acoustic emission. During a tensile test, online monitoring using acoustic emission (AE) demonstrates a reduction in fracture development and propagation. The tensile test result exhibits that, Mg-1.5% B₄C nanocomposite has a better tensile strength (σ_ultimate = 125 MPa) than the Mg-0.5% B₄C nanocomposite (σ_ultimate = 115 MPa). AE results show that the hit begins at 26 µs for Mg-1.5% B₄C nanocomposite, whereas for Mg-0.5% B₄C nanocomposite, it begins at 14 µs. Thus, AE results show that an increase in B₄C nanoparticles in the composites will prevent hits from occurring. The SEM and atomic force microscopy analyses were performed on the tensile-tested specimens to find the distinguishing characteristics. Owing to the inclusion of the B₄C, the Mg-1.5% nano B₄C composite has a longer ignition time in the thermogram of TGA and greater tensile strength than the Mg.