Surface composites are viable choices for various applications in the aerospace and automotive industries. Friction Stir Processing (FSP) is a promising method for fabricating surface composites. Aluminum Hybrid Surface Composites (AHSC) are fabricated using the FSP to strengthen a hybrid mixture prepared with equal parts of Boron carbide (B₄C), Silicon Carbide (SiC), and Calcium Carbonate (CaCO₃) particles. Different hybrid reinforcement weight percentages (reinforcement content of 5% (T1), 10% (T2), and 15% (T3)) were used in fabricating AHSC samples. Furthermore, different mechanical tests were performed on hybrid surface composite samples with different weight percentages of the reinforcements. Dry sliding wear assessments were performed in standard pin-on-disc apparatus as per ASTM G99 guidelines to estimate wear rates. The presence of reinforcement contents and dislocation behavior was investigated using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) studies. The results indicated that the Ultimate Tensile Strength (UTS) of sample T3 exhibited 62.63% and 15.17% higher than that of samples T1 and T2, respectively, while the Elongation (%) of T3 exhibited 38.46% and 15.38% lower than that of samples T1 and T2, respectively. Moreover, it was found that the hardness of sample T3 increased in the stir zone compared to samples T1 and T2, owing to its higher brittle response. The higher brittle response of sample T3 compared to samples T1 and T2 was confirmed by the higher value of Young’s modulus and the lower value of Elongation (%).

Hybrid composites are formed by incorporating more than one reinforcement into the parent alloy and these are considered to be one of the significant materials used for aerospace, automobile, defence applications. Even nano hybrid composites are also evolving as materials to be considered with prominence. Aluminum metal matrix hybrid composites especially Al7075 hybrid composites are known for superior strength to weight ratio and good wear resistance, that's why those are considered as most useful materials in the field of mechanical applications. Ease of manufacturing, low cost of production paved the way for aluminum hybrid composites to emerge itself in to one of the potential material for future applications in aerospace, automobile, defence sectors. In order to develop aluminum hybrid composites several reinforcements were been added along with the metal matrix. Reinforcements enhance the mechanical, physical and micro structural characteristics of the hybrid composites. Mechanical properties would get enhance with varied wt % of reinforcements. This article provides an overview on recent developments on aluminum metal matrix hybrid composites.