Performance improvement of GF/CF functionally gradient hybrid composite

Two kinds of functionally gradient materials (FGMs) were fabricated by changing the spatial distribution of GF and CF in polyphenylene sulfide (PPS) matrix. To measure the mechanical properties of FGMs and GF/CF/PPS isotropic composites, flexural tests and instrumented impact tests were performed. The flexural strengths and the flexural moduli of GF/CF/PPS isotropic composites increased in proportion to the relative content of CF to GF. On the other hand, total absorbed impact energy of GF/CF/PPS isotropic composites decreased with the increment of CF relative volume ratio. Compared with GF/CF isotropic composite, FGM with CF-rich side at the front showed higher flexural strength and higher flexural modulus. In addition, FGM with CF-rich side at the front showed similar flexural strength and flexural modulus to those of GF/CF isotropic composite. Total impact absorption energies of the two FGMs were similar regardless of compositional difference beteen the two FGMs.