Pore-size-dependent mechanical properties and biodegradation behavior of biomedical Zn-Li alloy scaffolds

Abstract

Zn-Li alloys have emerged as promising candidates for bone repair applications due to their excellent mechanical properties and osteogenic potential. In this study, porous Zn-0.7Li scaffolds were fabricated via infiltration casting, with adjustable spherical pore sizes to achieve high porosity and thin-walled structures. Increasing pore size from 550 μm to 950 μm was accompanied by a corresponding elevation in scaffold porosity from 65.6 % to 71.2 % and a concurrent increase in the average wall thickness from 0.21 mm to 0.31 mm. Herein, the compressive yield strength decreased exponentially with rising porosity, while the degradation weight loss rate correlated linearly with specific surface area. The compressive yield strength of Zn-Li scaffolds were enhanced by solid solution strengthening and β-LiZn4 phase on the Zn matrix, superior to Zn-Mg alloy and pure Zn scaffolds at equivalent porosity. Besides, Zn-0.7Li scaffolds showed accelerated degradation due to their larger specific surface area. Based on the evolution of pore structure and mechanical properties during degradation, a mechanical performance decay model was established, which predicted the mechanical half-life of the Zn-0.7Li scaffolds as 61–122 days. This study provides insights into the quantitative relationship between pore structure and physicochemical properties of biodegradable bone repair materials, exploring feasible technical routes for developing high-performance scaffolds.