Residual stress relaxation of hydroxyapatite/316L asymmetrical functionally gradient material fabricated by hot-pressing

Abstract

Abstract A composite combining hydroxyapatite with varying ratios of 316L to form an asymmetrical functionally gradient material was successfully prepared using a hot-pressing technique. The results show obvious macroscopic gradient changes in the functionally gradient material. Although the components change continuously on a microscopic scale, the interfaces between gradient layers remain tightly integrated. The addition of 316L powder changes the fracture modes of the composites and improves their mechanical properties. The hydroxyapatite content in the composites varies with different gradient layers, which is in keeping with the composite design. The phases of hydroxyapatite and 316L dissolve into each other to some degree during hot-pressing and the combining mechanism of the two phases in the gradient layers is dissolving behavior. Thermal stress relaxation calculation indicates that the gradient structure of the asymmetrical HA/316L functionally gradient material has a significant impact on the relaxation of residual thermal stress.