Forming quality, mechanical properties, and anti-inflammatory activity of additive manufactured Zn-Nd alloy

Zinc (Zn) has recently been recognized as a promising bone repair material due to its inherent biodegradability and favorable biocompatibility. In this work, rare earth neodymium (Nd) was introduced into a Zn-based alloy fabricated using a laser powder bed fusion (LPBF) process. Results showed that addition of Nd significantly improved the melt fluidity and reduced the evaporation of Zn, thereby achieving parts with a high densification rate of 98.71%. Significantly, the Nd alloying treatment effectively refined the grain size from 25.3 to 6.2 µm. NdZn5 eutectics precipitated and contributed to a second-phase strengthening effect. As a result, the tensile strength increased to (119.3±5.1) MPa and the Vickers hardness to (76.2±4.1). Moreover, the Zn-Nd alloy exhibited good anti-inflammatory activity, as the Nd ions released during degradation had a strong affinity with cell membrane phospholipids and consequently inhibited the release of inflammatory cytokines. It also presented favorable cytocompatibility, showing great potential as a bone repair material.