Processing and mechanical behavior of lamellar structured degradable magnesium-hydroxyapatite implants

Area of Science:

• Biomaterials Science
• Materials Engineering
• Orthopedic Implants

Background:

• Multilayered composites offer tunable mechanical properties compared to bulk materials.
• Magnesium-based composites are increasingly popular for temporary implant applications due to their biodegradability.

Purpose of the Study:

• To fabricate lamellar magnesium-nano-hydroxyapatite (Mg-HA) metal matrix composites (MMCs) for degradable implant applications.
• To evaluate the mechanical properties and corrosion behavior of Mg-HA composites with varying HA content.

Main Methods:

• Fabrication of Mg-HA composites (8, 10, 15 wt% HA) using ball milling and spark plasma sintering.
• Characterization of composite structure and phase analysis using X-ray diffraction (XRD).
• Evaluation of corrosion behavior via potentiodynamic polarization tests and mechanical properties (Vickers hardness, Young's modulus, fracture toughness) using nano-indentation.

Main Results:

• Ball milling for 20 hours resulted in HA particles coating Mg flakes.
• Spark plasma sintering formed a lamellar Mg structure with HA and MgO at inter-lamellar sites.
• Mg-10% HA composite exhibited the best corrosion resistance and highest Vickers hardness.
• Mg-8% HA composite showed higher Young's modulus and fracture toughness.

Conclusions:

• Lamellar Mg-HA composites demonstrate tunable mechanical properties and improved corrosion resistance.
• Mg-HA composites with 8% and 10% HA are promising candidates for temporary degradable orthopedic implants.
• The study highlights the potential of Mg-HA composites for enhanced biocompatibility and performance in medical devices.