Abstract: HA(ZrO₂)-316L stainless steel fibre asymmetrical functionally gradient biomaterial(FGM) was successfully fabricated under 1100℃ by low pressure hot isostatic pressing(HIP) technique. Metallographical
microscope, SEM, EDXA analysis were carried out to examine the microstructure and elemental contents of the asymmetrical FGM. The results show that asymmetrical stepwise change of volume ratio of
316L stainless steel fibre according to 20%→15%→10%→5% can be corresponded in the FGM. 316L stainless steel fibre is randomly and evenly distributed in the FGM.
316L stainless steel fibre is enwrapped in the HA(ZrO₂) matrix and both integrate each other tightly. The interface of 316L stainless steel fibre and HA(ZrO₂) matrix is partly concavo-convex. The approach
also indicates that some Fe element diffusion of the toughing phase takes place in the HA(ZrO₂) matrix and no Ca, P element diffusion of the matrix takes place in 316L stainless steel fibre toughing
phase. Both matrix and toughing phase are relatively independent and no chemical reaction is observed in the FGM. With the increase of HA contents, both fracture toughness and Young’s modulus of HA(ZrO₂)-316L
stainless steel fibre composites are gradually reduced, which leads to mechanical properties relaxation design of the FGM. It is suggested that fibre pulling out and interbedded crack deflexion are the major
toughing mechanism in the asymmetrical FGM.

Key words: functionally graded material（FGM）, biomaterial, hydroxyapatite（HA）, 316L stainless steel fibre, hot isostatic pressing（HIP）, microstructure