Effect of sintering path on the microstructural and mechanical behavior of aluminum matrix composite reinforced with pre-synthesized Al/Cu core-shell particles

The effect of different sintering techniques (vacuum sintering, hot-pressing, spark plasma sintering) on microstructure and mechanical properties were investigated for pre-synthesized core-shell (Al/Cu) particles reinforced Al matrix composites (AMC). In the first step, copper was deposited on aluminum powder particles by galvanic replacement method to synthesize Al/Cu particulates. In the next step, green compacts of Al/Cu core-shell particles reinforced AMCs were prepared by using vacuum sintering (VS), hot-pressing (HP) and spark plasma sintering (SPS). The microstructure and phase analysis of the prepared composites were performed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) while their mechanical properties were evaluated by performing compression test and microhardness test. The results revealed that the sintering path has a pronounced impact on the properties of prepared composites. Depending on the consolidation technique, the deposited Cu in the core-shell structure is transformed in-situ into various types of intermetallic. This results in specially tailored microstructures with improved strength along with varying toughness depending upon the sintering technique. Mechanical characterization showed that the spark plasma sintered composite has the highest microhardness and compressive strength. To meet the current industrial requirements for structural and functional applications, this study provides a methodology to obtain tailor-made microstructure of AMCs with much improved mechanical characteristics.