Experimental investigation on newly developed ultrafine-grained aluminium based nano-composites with improved mechanical properties

The present work describes the structural evolution associated with grain refinement and superior mechanical properties by the addition of nano-size Al2O3 and Y2O3 particulates into monolithic A16063 alloy matrix. Mechanical milling (MM) and mechanical alloying (MA) was employed to obtain nanostructured A16063 alloy matrix with uniform distribution of ceramic reinforcement particulates. The milled-compacted-sintered samples were hot extruded to further densify the nano-composites and make the distribution of particles uniform in the material. The final hot extruded samples were examined by high resolution-scanning electron microscopy (HR-SEM), field emission-scanning electron microscopy (FESEM), X-ray diffraction (XRD) analysis and were mechanically tested for hardness and mechanical strength. Detailed (transmission electron microscopy) TEM studies were carried out for hybrid reinforced nano-composites which exhibit superior properties over monolithic Al6063 alloy and singular reinforced nano-composites. Results show that the 0.2% yield strength (0.2% YS), ultimate tensile strength (UTS), work of fracture (WOF) were improved over the unreinforced monolithic A16063 alloy and failure strain was decreased in reinforced nano-composites.

► A method for preparing UFG aluminium nano-composites through PM route discussed.
► Superior mechanical properties were achieved using hybrid nano-composites.
► Uniform distribution and good interfacial integrity of particles was attained.
► Duplex nature of microstructure was observed.
► No detectable reaction of inter-phases was found between matrix and reinforcements.