Empirical Analysis of Minimum Interlayer Number for Functionally Graded Materials

Abstract

Minimum interlayer numbers of functionally graded materials (FGMs) is studied based on the empirical analysis of thermal stress due to the differences in the thermal expansion coefficient Δα and temperature ΔT between sintering and room temperatures. It is found the maximum Δα, ΔT, ΔαΔT and the minimum interlayer number necessary to produce a NiCr/Fly ash FGM structure without cracking are 4.0×10⁻⁶ K⁻¹, 1080 K, 0.043 and 2, respectively. The criterion, ΔαΔT < 0.043, is derived and confirmed to be valid for available FGM systems.