The
x=0.2,0.4,0.6,80 layers of (l -
x) (80%B
4C-20%SiC)/
xC (volume fraction) Functionally Graded Materials were hot-pressed respectively. The density, linear thermal expansion, elastic modulus and flexural strength were tested. There are crackles in FGMs of 6 and 11 layers that are designed by linear function. The S-type function of compositional distribution as a designed method applied to investigate FGM. As a result the flexural strength is 216 MPa and thermal shock resistance Δ
fc>500℃ for 11 layers (
x=0.2~l) FGMs of S-type.