‘The micro/nano reinforced particle’ aluminum metal matrix composites (Al-MMCs) are widely used in manufacturing sector due to light-weight, superior strength-to-weight ratio, better fracture toughness, improved fatigue, and tensile property, enhanced corrosion resistance to harsh environment, etc. This article provides an overview of the manufacturing processes and different reinforcing elements used during the synthesis of Al-MMCs. Generally, the reinforced particles like carbides, nitrides, and compounds of oxides are used. Different organic, inorganic, industrial and agricultural waste which can be used for reinforcement in the aluminum matrix is highlighted with their feasible applications. The common mechanical properties (i.e. hardness, tensile and compressive strength, etc.) reported by different researchers are thoroughly discussed with the aim to highlight the amount of reinforcement and improvement occurred during processing. The formation and methodology for mixing condition and sintering behaviour of Al-MMCs are discussed to impart knowledge about the processing circumstances in powder metallurgical route. The affecting conditions during operating and responsible factor for the tribological behaviour are deliberated in a precise manner to recognize the potentiality of reinforcing particles in Al-MMCs. Finally, the different shortcomings and future prospects of the Al-MMCs are given to encourage the future research directions.

The study focuses on the microstructural, phase transformation, and physical and mechanical aspects of aluminum/zinc oxide composite produced by a hybrid microwave sintering technique. In the present case, zinc oxide nanorods were synthesized through a cost-effective thermal decomposition method. The obtained zinc oxide nanorods’ length was in the range of 76–168 nm observed through high-resolution transmission electron microscopy images and crystallinity nature was confirmed by the bright spot in the selected area electron diffraction pattern. Two different wt% (i.e. 0.5 and 2) of zinc oxide nanorods were utilized for the fabrication of the composite material. The diffraction pattern of the milled powder and energy dispersive spectroscopy results shows effective diffusion of zinc oxide nanorods in the aluminum. The elemental mapping of milled powder illustrates the uniform distribution of the reinforcement over matrix material. The micro-hardness results exhibit a higher hardness of 27.78% with a small fraction of 2 wt%. The nano-indentation results confirm the improvement in the nano-hardness by 32.21% with 2 wt% of zinc oxide with a marginal decrease in elastic modulus by 4.92%.

In this work Al-ZnO-Y₂O₃ hybrid composites were fabricated utilizing powder metallurgy and hybrid microwave sintering approach from the powder blend of Al, ZnO and Y₂O₃. Depth sensing nano-indentation technique was adopted to assess the nano-hardness and elastic modulus of the composite material. Thermal analysis of the composite materials was done to gain an insight into surface decomposition and phase transformation behaviour. A strong interfacial bonding with clear interface between matrix and reinforcement was observed during the microstructural analysis of the composite material. The results of the current study exhibit ~89% improvement in the nano-hardness and ~11% improvement in the elastic modulus value. The improvement in the material response is attributed to the reasonably uniform distribution of ZnO and Y₂O₃ in the hybrid composite materials. The results of this study validate the capability of combined presence of ZnO and Y₂O₃ reinforcements to enhance the hardness and elastic modulus of aluminium.