Mechanical property, in vitro biodegradable behavior and biocompatibility of additive manufactured biomedical Zn-0.8Cu alloy

Laser powder bed fusion (LPBF), owing to its high manufacturing precision and ability to produce patient-specific designs, has initiated a revolution in the field of biodegradable biomedical implants. However, its unique layer-by-layer building strategy inevitably introduces anisotropy in both microstructure and properties. In this study, we systematically investigated the microstructure, mechanical properties, and degradation behavior of LPBF processed Zn-0.8Cu alloys. In addition, we elucidated the underlying microstructural influence on tensile and corrosion behavior. The results demonstrated that samples built along the vertical direction exhibit a superior strength-ductility balance compared with their horizontal counterparts. The enhanced strength was primarily from the higher density of CuZn 4 nanoprecipitates in the vertical specimens, whereas cracks tended to propagate through multiple grains to consume more energy when stretched, which simultaneously enhances ductility. Meanwhile, the presence of finer grains facilitated the formation of a stable surface oxide layer, and the decreased fractions of CuZn 4 reduced the galvanic corrosion, thereby imparting higher corrosion resistance in horizontal specimens than vertical specimens. Moreover, the alloy exhibits excellent biocompatibility, supporting robust cellular proliferation. Collectively, these findings provide new insights into the process-structure-property relationships of LPBF fabricated biodegradable implants and offer guidance for their future design and optimization. • Vertical samples exhibited more CuZn 4 precipitates than horizontal ones. • Vertical samples had higher strength because of a higher density of CuZn 4 nanoprecipitates. • Vertical samples had weaker corrosion properties because of stronger galvanic corrosion. • LPBF-fabricated Zn-0.8Cu exhibited cell proliferation-promoting effects.