Nano-SiC reinforced Zn biocomposites prepared via laser melting: Microstructure, mechanical properties and biodegradability

Abstract

Zn has been regarded as new kind of potential implant biomaterials due to the desirable biodegradability and good biocompatibility, but the low strength and ductility limit its application in bone repairs. In the present study, nano-SiC was incorporated into Zn matrix via laser melting, aiming to improve the mechanical performance. The microstructure analysis showed that nano-SiC distributed along Zn grain boundaries. During the laser rapid solidification, nano-SiC particles acted as the sites for heterogeneous nucleation, which resulted in the reduction of Zn grain size from 250 μm to 15 μm with 2 wt% SiC (Zn-2SiC). Meanwhile, nano-SiC acted as a reinforcer by virtue of Orowan strengthening and dispersion strengthening. As a consequence, the nanocomposites showed maximal compressive yield strength (121.8 ± 5.3 MPa) and high microhardness (72.24 ± 3.01 HV), which were increased by 441% and 78%, respectively, compared with pure Zn. Moreover, fracture analysis indicated a more ductile fracture of the nanocomposites after the incorporation of nano-SiC. In addition, the nanocomposites presented favorable biocompatibility and accelerated degradation caused by intergranular corrosion. These findings suggested that the nano-SiC reinforced Zn biocomposites may be the potential candidates for orthopedic implants.