Hygrothermal aging effects on fiber-metal-laminates with engineered interfaces

This short work is to communicate the influence of hygrothermal aging on the mechanical performances of fiber-metal-laminates (FMLs) with various ingenious metal surface treatments, namely, nano-scale electrochemical sculpture (NES), the conventional surface polishing (PS) and NaTESi anodizing (NaTESi). The specimens with different edge conditions were prepared using milling or wire-electrode cutting and subjected to hygrothermal aging treatment in a climatic test chamber at 60 °C and 96% relative humidity. Interlaminar shear and flexural testing results showed that the wire-electrode cutting method produced edges with exposed fibers and spalling resin after hygrothermal aging, while the milling cutting method resulted in edges with a micro-porous and defective surface, but without exposing fibers or spalling resin. The degree of reduction in interlaminar shear strength (ILSS) and flexural strength varied depending on the surface treatments and machining methods used. After undergoing hygrothermal aging, the wire-electrode cutting method causes a greater decrease in ILSS compared to the milling cutting method. This reduction is particularly pronounced in specimens with weaker interfacial bonding strength, in which the ILSS of wire-electrode cut FMLs-PS decreased by 32.5%, while that of FMLs-NES decreased by 17.8%.