Microstructure development of AM-fabricated pure Zn with heat-treatment and its mechanical properties, degradation behavior, and biocompatibility

Abstract

The fabrication of zinc (Zn) parts devoid of inherent defects through Powder Bed Fusion-Laser Beam (PBF-LB) remains a formidable challenge. This study focuses on the optimization of process parameters and the implementation of tailored heat treatment to achieve high-performance PBF-LB fabricated (PBF-LBed) pure Zn bulk and scaffolds. Microstructural analysis, residual stress assessment, mechanical property testing, electrochemical experiments, immersion tests, in vitro and in vivo evaluations were conducted. The research results revealed that, under optimized process parameters and subsequent annealing, the yield strength, ultimate tensile strength, and ductility of PBF-LBed parts exhibit remarkable enhancements. Concurrently, the grain size was refined to 3 μm, accompanied by a notable improvement in biocompatibility. It could be roughly concluded that the microstructure refinement obtained through the heat treatment could significantly enhance their mechanical and electrochemical performances. Meanwhile, an appropriate Zn ion release rate achieved through grain refinement might created a more conducive microenvironment for new bone formation. Consequently, heat-treated PBF-LBed pure Zn scaffolds exhibits superior performance and application potential compared to untreated scaffolds.

Keywords

• Zn implants
• PBF-LB
• Heat treatment
• Mechanical properties
• Biocompatibility