Effect of hybridization and stacking sequence on damage development in AWJ machining of Al/FRP/Al FML composites

In this study, 5 different Al2024/FRP/Al2024 metal stacked composites were produced and their machinability by abrasive water jet machining (AWJM) method was investigated. Synergistic interaction of these materials offers new and improved properties, but machinability remains an area of research due to widely varying mechanical properties. The effects of different stacking and traverse speed on hole quality in cutting with AWJM were determined. The hole diameter deviation (HDD) ratio, kerf, delamination, hole circularity, and surface morphology were analyzed. Result of the current study showed that the increase in traverse speed caused an increase in the HDD ratio, in the visibility of the cutting starting point, in the deviation of circularity, and in the bore-hole damage formation. In all stacks with CFRP, an average deviation of 5 % at the hole entrance and 4 % at the hole exit occurred at a traverse speed of 1000 mm/min. At 400 and 600 mm/min traverse speeds, an average of 2.8 % deviation occurred at the hole entrance and an average of 2.13 % at the hole exit. This proves that the traverse speed has a significant effect on the hole diameter. In addition, as the traverse speed decreased, it was noticed that the layers separated from each other, causing delamination, and therefore the thickness of the FML increased. Different defects were observed to occur in FRP structures used in FML with SEM analysis. Intralayer defects were more dominant in GFRP laminate, whereas interlayer defects were found to form in CFRP laminate.