Synthesis and wear characterization of Al based, free standing functionally graded materials: effects of different matrix compositions

In the present study, the effects of different matrix compositions, namely, Al, Al–3.35 wt.% Cu and Al–4.08 wt.% Mg, on the resulting gradient of the SiC particulates along the bulk functionally graded materials (FGMs) synthesized by the simple, cost-effective, high yield and high deposition rate gradient slurry disintegration and deposition technique is investigated. For Al/SiCp and Al–Cu/SiCp, an increase in weight percentage of SiCp along the deposition direction with an attendant increase in porosity and microhardness was observed. However, for Al–Mg/SiCp, reverse SiCp gradient was observed, with porosity and microhardness decreasing along the deposition direction. A lower overall porosity was also observed for Al–Mg/SiCp. A reduction in CTE value of the high SiCp end was observed when compared with the low SiCp end for all three ingots. The high SiCp end was also found to be more wear resistant than the low SiCp end, except for Al–Cu/SiCp. The effects of different Al matrix compositions with the microstructural development, microhardness and wear results are correlated.