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In this study, 10%β-Ca 3 (PO 4 ) 2 /Mg-6%Zn (wt.%) composites with Mg-6%Zn alloy as control were prepared by powder metallurgy. After hot extrusion, the as-extruded composites were aged for 72 h at 150 °C. The effects of the adding β-Ca 3 (PO 4 ) 2 , hot extrusion and aging treatment on their microstructure, mechanical properties and corrosion resistance were investigated. The XRD results identified α-Mg, MgZn phase and β-Ca 3 (PO 4 ) 2 phase in these composites. After hot extrusion, grains were significantly refined, and the larger-sized β-Ca 3 (PO 4 ) 2 particles and coarse MgZn phases were broken into linear-distributed β-Ca 3 (PO 4 ) 2 and MgZn phases along the extrusion direction. After aging treatment, the elements of Zn, Ca, P and O presented a more homogeneous distribution. The compressive strengths of the β-Ca 3 (PO 4 ) 2 /Mg-Zn composites were approximately double those of natural bone, and their densities and elastic moduli matched those of natural bone. The immersion tests and electrochemical tests revealed that the adding β-Ca 3 (PO 4 ) 2 , hot extrusion and aging treatment could promote the formation of protective corrosion product layer on the sample surface in Ringer's solution, which improved corrosion resistance of the β-Ca 3 (PO 4 ) 2 /Mg-Zn composites. The XRD results indicated that the corrosion product layer contained Mg(OH) 2 , β-Ca 3 (PO 4 ) 2 and hydroxyapatite (HA). The cytotoxicity assessments showed the as-extruded β-Ca 3 (PO 4 ) 2 /Mg-Zn composite aged for 72 h was harmless to L-929 cells. These results suggested that the β-Ca 3 (PO 4 ) 2 /Mg-Zn composites prepared by powder metallurgy were promising to be used for bone tissue engineering. [ABSTRACT FROM AUTHOR]

Magnesium alloys have been regarded as potential degradable biomedical materials due to their suitable mechanical properties and excellent biocompatibility. In this study, Mg-Zn alloys were fabricated by powder metallurgy and then hot extruded. The effects of Zn concentration and heat treatment on their microstructure, mechanical properties and corrosion behavior were investigated. The compression test results showed that their mechanical properties were suitable for bone tissue engineering. The corrosion behavior of Mg-Zn alloys was analyzed by immersion tests and electrochemical tests in Ringer's solution. The results revealed that the increasing Zn concentration reduced the corrosion potential but increased corrosion current because severe micro-galvanic corrosion was caused by more large-size intermetallic phases. Although solid solution treatment could reduce intermetallic phase amounts, it caused micropores on the surface. And these micropores could resulted in the pitting corrosion and reduce the corrosion resistance. Notably, aging treatment could reduce the segregation of Zn and promote the compactness and uniformity of corrosion product layer on the surface, leading to the improvement of corrosion resistance. In addition, the as-extruded Mg-6%Zn alloy (wt.%) aged for 72 h was harmless to L-929 cells in cytotoxicity test. Consequently, the as-extruded Mg-Zn alloys prepared by powder metallurgy are promising to develop to be ideal biodegradable implants for bone tissue engineering. [ABSTRACT FROM AUTHOR]

Three types of Mg–Al-based anodes Mg–3Al–Zn, Mg–6Al–Zn, and Mg–6Al–Sn (wt.%) alloys were produced. The influences of Al and Sn on microstructure, corrosion behavior, electrochemical property, and battery performance were studied. The experimental results show that the introduction of Al and Sn leads to the significant grain refinement and the decrease of hydrogen evolution rate of Mg–Al-based anodes. The more Al element added in alloy, the more β-Mg 17 Al 12 phases scattered at the grain boundaries, which can accelerate the dissolution of magnesium matrix. Thus, Mg–6Al–Zn manifests stronger discharge activity than Mg–3Al–Zn. The added Sn is capable to propagate Mg 2 Sn phases along the grain boundaries and to suppress the precipitate of coarse β-Mg 17 Al 12 phases in Mg–6Al–Sn. Significantly, the fine grain with tiny second phases existed in Mg–6Al–Sn is beneficial to facilitate the self-peeling of discharge products by forming the micro-cracks on the alloy surface during discharge process. The results suggest that Mg–6Al–Sn exhibits a higher electrochemical activity and utilization efficiency, specifically, a better discharge stability at the large current density for long-time. The average cell voltage, power density, specific capacity and anodic efficiency of Mg–6Al–Sn anode for Mg-air battery within 12 h at 50 mA cm−2 were 1.097 V, 54.85 mW cm−2, 1423 mA h g−1 and 63.7%, respectively. • Al and Sn refine grain, improve alloys' discharged potential and anodic efficiency. • The influences of second phase and grain size are analyzed in detail. • AT61 alloy exhibits the highest cell voltage and maximal anodic efficiency. • AT61 anode is potential for ideal Mg-air battery serving at high current density. [ABSTRACT FROM AUTHOR]