Characterisation of four-layered Al-Al2O3 functionally graded material prepared through powder metallurgy and pressureless sintering

In this research study, four-layered aluminium-aluminium oxide (Al-Al2O3) functionally graded material (FGM) was prepared through powder metallurgy (PM) route considering 0%, 10%, 20% and 30% weight percentage of ceramic concentration. The sintering temperature and time used are 620°C and 120 min following two-step sintering cycle. The prepared FGM samples were characterised by densification and shrinkage. Microstructural and elemental analyses were carried out by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Mechanical characterisation was carried out using Vickers microhardness tests. It was observed that cylindrical FGM specimens (green compact) were successfully prepared and diameter of cylindrical structure was decreased after sintering process. It was also observed that there was no existence of macro-crack or micro-crack within the individual layer or at the interface and smooth transition occurred from one layer to next layer. Elemental analyses confirmed the gradient distribution of material composition layer by layer.