A study on the mechanical and erosion wear of functionally-layered polymer composites and hybrid functionally-layered polymer composites

The present study focuses on the mechanical and erosive wear properties of functionally-graded polymer materials (FGPMs) and functionally-graded hybrid composites. Polyester resin is used as a polymeric matrix, while titanium dioxide (TiO₂) and aluminum (Al) as particles and glass fiber (GG) as fiber reinforcements are used in the composites. The samples are fabricated through the lay-up lamination technique. Initially, four-layered FGPMs were fabricated using TiO₂ and Al particles individually in weight percentages varying from 2 to 8% (by wt). Then, four-layered hybrid functionally-graded composites were prepared using 2–4% (by wt) Al and TiO₂ along with two layers of glass fibers. A comparison among functionally-graded materials and functionally-graded hybrid materials in terms of mechanical strength (tensile, flexural and interlaminar) and erosion behavior is evaluated on a universal testing machine and air jet erosion testing apparatus, respectively. The improved tensile strength is shown by aluminum-based functionally-graded and hybrid functionally-graded composites owing to their greater ductility. Nevertheless, titanium dioxide-based functional- graded and hybrid functional-graded composites exhibited greater flexural strength due to their high hardness. From the erosion results, Al and TiO₂ functional-graded composites revealed semi-ductile and semi-brittle behavior, respectively. Moreover, hybrid functional composites display altered material behavior at their extreme layers. Two layers of glass fiber (GG) with Al (2.4% by wt) filler functional composite achieved 1.91% maximum tensile strength compared to Al (2, 4, 6, 8% by wt) filler composite.