A Heterogeneously structured Mg-Zn laminate alloy for gradient degradation behavior.

Area of Science:

• Biomaterials Engineering
• Materials Science
• Metallurgical Engineering

Background:

• Magnesium alloys are promising for short-term implants but require controlled degradation rates.
• Conventional bulk magnesium alloys lack the ability to precisely regulate degradation.
• Clinical requirements necessitate tailored degradation profiles for biodegradable implants.

Purpose of the Study:

• To develop a magnesium-zinc laminate alloy with a heterogeneous gradient structure (HGS) for controlled degradation.
• To investigate the synergistic interplay of compositional and structural gradients on degradation behavior.
• To provide a scientific basis for next-generation biodegradable metallic materials.

Main Methods:

• Fabrication of a Mg-Mg2Zn-Mg4Zn-Mg6Zn-Mg4Zn-Mg2Zn-Mg (MZM) laminate alloy using a two-pass hot rolling and quenching process.
• Implementation of a heterogeneous gradient structure (HGS) strategy with a symmetric gradient in zinc concentration (0-6 wt%).
• Evaluation of the alloy's in vivo degradation profile and rates.

Main Results:

• The MZM alloy demonstrated a progressively increasing degradation profile.
• An initial low in vivo degradation rate of 0.054 ± 0.0062 mm/year was observed.
• A subsequent increased degradation rate of 0.180 ± 0.003 mm/year was recorded, both within the biosafe range.

Conclusions:

• The developed MZM alloy with HGS effectively achieves tunable degradation rates for biodegradable implants.
• This approach offers a viable strategy for engineering magnesium alloys with clinically relevant degradation profiles.
• The findings support the advancement of biodegradable metallic materials for medical applications.