A Critical Review on Fiber Metal Laminates (FML): From Manufacturing to Sustainable Processing

Abstract

Composite materials such as Fiber Metal Laminates (FMLs) have attracted the interest of the aerospace and automotive industries due to their high strength to weight ratio, but to use them as structures it is necessary to master the manufacturing and wiring techniques of these materials. Therefore, this paper aims to address and summarize the drilling and milling processes in FMLs based on a literature review of papers published from 2000 to 2023. Parameters used in multi-material manufacturing and machining such as drilling and milling, tool geometry, tool coating, lubricants and coolants published by researchers were analyzed, compared and discussed. Machining process parameters related to sustainability were also analyzed. A SWOT analysis was carried out and discussed to identify opportunities for improvement in the machining process. There are opportunities to develop the surface treatment of aluminum alloys, such as testing other combinations than those already used, testing non-traditional surface treatments and manufacturing modes, and developing sustainable techniques during the FML manufacturing process. In the area of tooling, the opportunities are mainly related to coatings for tools and changing machining parameters to achieve an optimum finished part. Finally, to improve the sustainability of the process, it is necessary to test coated drills under cryogenic conditions to reduce the use of lubricants during the machining process.

Investigations on the development of impact-resistant thermoplastic fibre hybrid composites from glass and steel fibre

“…[5][6][7] The hybridisation of high-performance fibres with metals has so far been mainly limited to the macroscopic scale, involving layered combination of metal and highperformance fibres as hybrid fibre composites. [8][9][10] At the macroscopic scale, a notable technique is laminate hybridisation, where alternating layers of metal sheets and FRP are systematically combined. These composites, known as fibre-metal laminates (FMLs), include metal sheet layers together with FRPs, as seen in examples such as CARALL (carbon fibre reinforced epoxy/aluminium foil laminate), ARALL (aramid fibre reinforced epoxy/ aluminium foil laminate) and GLARE (glass fibre reinforced epoxy/aluminium foil laminate).…”

“…These composites, known as fibre-metal laminates (FMLs), include metal sheet layers together with FRPs, as seen in examples such as CARALL (carbon fibre reinforced epoxy/aluminium foil laminate), ARALL (aramid fibre reinforced epoxy/ aluminium foil laminate) and GLARE (glass fibre reinforced epoxy/aluminium foil laminate). 8 The focus of the studies was mostly on the effects of interlayer hybrid ratio and stacking sequence on the mechanical properties of laminated composites. 11,12 However, under loading conditions, the macroscopic layer-by-layer arrangement of FMLs can lead to stress concentrations at the interfaces between the aluminium foil and the fibre-reinforced composite layers, resulting in layer delamination and premature failure of the composite components.…”

“…These composites, known as fibre-metal laminates (FMLs), include metal sheet layers together with FRPs, as seen in examples such as CARALL (carbon fibre reinforced epoxy/aluminium foil laminate), ARALL (aramid fibre reinforced epoxy/aluminium foil laminate) and GLARE (glass fibre reinforced epoxy/aluminium foil laminate). 8 The focus of the studies was mostly on the effects of interlayer hybrid ratio and stacking sequence on the mechanical properties of laminated composites. 11,12…”

Effect of Heating and Cooling of Aluminium-Based Fibre-Metal Laminates on Their Tensile Strength

“…A composite material as a combination of two or more insoluble materials differing in species or chemical composition are usually produced to produce a structural material with suitable mechanical, electrical, thermal, tribological or other properties (Chandrasekar et al, 2017).They usually contain fibres or phase particles that are stiffer and more durable than the matrix. Many reinforcement materials also provide good thermal and electrical conductivity, a low coefficient of thermal expansion or good wear resistance (Costa et al, 2023). Fibre metal laminates (FMLs) consist of alternating layers of metal and a polymer matrix composite reinforced with continuous fibres.…”

Helical Milling and Drilling for Hole-Making in CARALL: Experimental Evaluation

“…The difference in the thermo-mechanical properties of the two phases affects the metal-cutting process. Distinctive properties between the metal and composites can affect the dimensional accuracy of drilled holes [7][8][9]. Also, improper selection of the process variables can increase the thrust load and lower the hole quality [10].…”