Synthesis, microstructure and mechanical properties of porous MgZn scaffolds

Magnesium alloys have been intensively studied as biodegradable implant materials, as their mechanical properties render them promising candidates for bone tissue engineering applications. In the present work, porous Mg–4 wt% Zn and Mg–6 wt% Zn scaffolds were prepared using a powder metallurgy process. The effects of the porosity and Zn content on the microstructure and the mechanical properties of the fabricated scaffolds were studied. The above mentioned fabrication process involved sequential stages of mixing and compression of Mg and Zn powders with carbamide materials as space-holder particles followed by sintering the green compacts at different temperatures below the melting point of Mg. The results indicate that the porous MgZn specimens with a porosity and pore size of approximately 21–36% and 150–400 μm, respectively, could have enhanced mechanical properties comparable with those of cancellous bone. In addition, an increase in the amount of Zn in the applied alloy gives rise to a significant refinement of magnesium grain size and an improvement in the mechanical properties, such as the compression strength, of the porous MgZn specimens. Furthermore, according to the results, the porous MgZn alloy could be considered one of the most promising scaffold materials for hard tissue regeneration.

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► Synthesis of porous MgZn scaffold via the powder metallurgy process.
► Optimum sintering temperature to synthesise porous MgZn specimens was found to be 550 °C.
► Mg7Zn3 and MgZn phases can be formed during synthesis of porous MgZn scaffold through the powder metallurgy process.
► Increment in the Zn element of the applied alloy gave rise to a significant refinement of magnesium grain size and improved mechanical properties of the porous MgZn specimens.
► Compared to the porous bioactive ceramic and polymeric scaffold, the porous MgZn specimens enjoy more appropriate mechanical properties which are closer to those of natural bone.