Mechanical and Microstructure Behavior of AA7050 Metal Matrix Composite Reinforced with TiO₂/BN

The alloys and composites of 7xxx aluminum are widely used in automobile, aerospace, and other related industries due to their incredible properties, such as high specific strength, low density, and robust processing performance. In this work, mechanical and microstructural characterization of the stir-cast AA7050 metal matrix composite reinforced with TiO₂ and BN is carried out by varying the weight percentages of the reinforcements. Microstructure and phase analysis of this new composite were observed with a field emission scanning electron microscopy (FESEM) and X-ray diffraction technique, while elemental analysis was performed with an energy-dispersive X-ray spectrometer. Microstructural examination of the developed composite shows that reinforcement particles are uniformly distributed throughout the matrix. The result also shows that the composite involving 2% TiO₂ and 1% BN has a maximum ultimate tensile strength and a hardness value of 255 MPa and 84.2 HRB, respectively. Increasing the TiO₂ content beyond 2 wt.% or BN content beyond 1 wt.% results in cluster formation, and hence the proportion of alloying elements is restricted to 2% and 1% for TiO₂ and BN, respectively. Microstructural examination of fracture surfaces revealed that ductile dimples and river lines are present.