An Investigation of Microstructural and Mechanical Behaviour of AA7050/Si3N4 Composites Fabricated Via Powder Metallurgy

This experimental study investigates the microstructural characteristics, density, and mechanical properties of AA 7050 composites incorporating 5 and 15 wt.% Si3N4. These composites were fabricated using a powder metallurgy (P/M) process. The fabrication involved the mechanical milling of AA 7050 and Si3N4 composite powders, followed by a systematic blending, pressing, and sintering procedure. The sintered samples have been characterised using an optical microscope. The fabricated samples are subject to density analysis, Hardness, compressive strength, impact and tensile strength have been experimentally investigated. The optical microscope reveals a uniform distribution of Si3N4 particles and the increase in hardness of AS15 is 43.06% compared to the basic material A0. A 50.08% enhancement in the compressive strength of the AS15 composite compared to the basic material (A0). The AS15 composite exhibits a maximum tensile strength of 230.65 MPa compared to all fabricated alloys and composites. Conversely, the AS15 composite shows a decreased effect strength of up to 9.25J compared to all fabricated composites, attributed to the increased weight percentage of Si3N4, which contributes to crack formation at the particle-matrix interface.