Mechanical, Thermal, and Tribological Performance of AL7075–Fe₂O₃ Metal Matrix Composites for Marine Applications

Abstract

The mechanical, thermal, tribological and microstructural properties of metal matrix composites (MMCs) made of Al7075 aluminum alloy and Fe₂O₃ reinforce by varying its percentage 3 %, 6 % and 9 % by weight are investigated in this study. Various tests such as tensile, compression, hardness, impact, wear and fatigue tests were conducted, all in accordance with ASTM protocols. The Laser Flash Method and dilatometry were used for the thermal characterisation. The microstructural features were investigated SEM/EDX and XRD. ANSYS finite element analysis (FEA) was used to simulate a marine propeller shaft sleeve for an axial loading of 1000 N. The ultimate tensile strength (521-583 MPa), compressive strength (408-464 MPa), Vickers hardness (167-205 VHN) and fatigue endurance (203-258 Mpa) of Fe₂O₃ content increase monotonously, while the wear resistance increases as Fe₂O₃ content improves. On the other hand, impact toughness (26↓15 J), thermal conductivity (152–118 W/m·K) and coefficient of thermal expansion (22–14×10⁻6 K⁻¹) also decreases. SEM shows some ductile fracture behavior at certain locations and the rest as mixed-brittle fracture behavior and EDX confirms the uniform dispersion of Fe₂O₃ in the material. FEA indicates the safety factor should be 2.74 and the maximum deformation of 1.47 mm under marine loading conditions. The 9 % Fe₂O₃ composite is concluded as the best composition material for the marine structural parts which are used for high dimensional stability, wear resistance and strength.

Keywords