Impact of machining control variables on the surface roughness and kerf taper angle in the AWJC of A356 - 10 wt.% Al₂O₃ functionally graded composite

This study delves into the topic of Abrasive Water Jet Cutting (AWJC) of Functionally Graded Composites (FGCs) made of Al6061-10 wt.% Alumina (Al₂O₃) through stir casting and horizontal centrifugal casting. Specifically, it examines how various cutting parameters affect surface roughness and kerf taper angle. Three separate zones were identified by microstructural analysis and Vickers microhardness testing in the manufactured FGC: an intermediate zone, a zone lacking in Al₂O₃, and an enriched zone. It is possible for the particle-dense area to reach a maximum hardness of 108 HV. Using a Taguchi L9 orthogonal array, machining trials were carried out on the Al₂Oₜ-rich zone, with feed, stand-off length, and abrasive supply rate being adjusted. By analyzing the Signal-to-Noise Ratio (SNR) and Analysis of Variance (ANOVA), it was shown that surface roughness was mainly affected by feed (47.11%), whereas kerf taper angle was mainly dictated by abrasive supply rate (78.12%). In order to minimize both responses, the optimal feed rate, stand-off length, and abrasive supply rates were found to be 10 mm/min, 1 mm, and 500 g/min, respectively. The creation of thicker chips, intensified particle collisions, and wider top kerfs was caused by increasing the feed and abrasive supply rates. As a result, surface roughness and kerf taper were enhanced. Machined surfaces analyzed with High-Resolution Scanning Electron Microscopy (HRSEM) showed plough marks, pits, ridges, and imbedded abrasives. These features became more pronounced as the abrasive supply rates were increased.