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In this study, in order to investigate the effects of alloying elements on the electrochemical behaviors of Al-based anodes, pure Al and Al-Mg-Ga-In alloys with different compositions (Al-0.25Mg-0.3Ga-0.3In, Al-1Mg-0.05Ga-0.15In and Al-2Mg-0.15Ga-0.05In (wt%)) were fabricated. The microstructure, corrosion behavior, electrochemical property, discharge performance and corroded morphology of the four experimental anodes were studied. Al-Mg-In-rich intermetallic compounds were observed in Al-Mg-Ga-In alloys. The results of the polarization curve and electrochemical impedance spectroscopy indicate that the addition of Mg acts as a critical component in improving the discharge activity of Al-based anode and contributes to a more negative electrode potential. According to the corrosion morphologies after discharge, it can be concluded that the addition of In element plays an essential part in forming corrosion pits on the surface of the anode while the addition of Ga element plays a vital role in destroying the surface passive layer to prevent passivation once corrosion starts.

Pure Zn and Zn-0.5%Li(wt) alloys were cast and extruded into the rods in this study. The micro structure and mechanical properties of Zn, Zn-0.5%Li and its mini tube were evaluated. With the addition of Li, both the UTS and elongation of extruded Zn-0.5%Li alloy increases to 364.9 MPa and 22% compared with Zn. The mini tube made of Zn-0.5%Li alloy shows the UTS of 296.2 MPa and elongation of 33%. The main strengthening mechanism of Zn-Li alloy is attribute to the pinning effects caused by nano LiZn4 precipitates. In conclusion, Zn-Li mini tube could be considered as potential absorbable stent material.

Porous Mg-based scaffolds have been extensively researched as biodegradable implants due to their attractive biological and excellent mechanical properties. In this study, porous Mg-6 wt.% Zn scaffolds were prepared by powder metallurgy using ammonium bicarbonate particles as space-holder particles. The effects of space-holder particle content on the microstructure, mechanical properties and corrosion resistance of the Mg-6 wt.% Zn scaffolds were studied. The mean porosity and pore size of the open-cellular scaffolds were within the range 6.7-52.2% and 32.3-384.2 µm, respectively. Slight oxidation was observed at the grain boundaries and on the pore walls. The Mg-6 wt.% Zn scaffolds were shown to possess mechanical properties comparable with those of natural bone and had variable in vitro degradation rates. Increased content of space-holder particles negatively affected the mechanical behavior and corrosion resistance of the Mg-6 wt.% Zn scaffolds, especially when higher than 20%. These results suggest that porous Mg-6 wt.% Zn scaffolds are promising materials for application in bone tissue engineering.

In this study, 10%β-Ca3(PO4)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 72h at 150°C. The effects of the adding β-Ca3(PO4)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-Ca3(PO4)2 phase in these composites. After hot extrusion, grains were significantly refined, and the larger-sized β-Ca3(PO4)2 particles and coarse MgZn phases were broken into linear-distributed β-Ca3(PO4)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-Ca3(PO4)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-Ca3(PO4)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-Ca3(PO4)2/Mg-Zn composites. The XRD results indicated that the corrosion product layer contained Mg(OH)2, β-Ca3(PO4)2 and hydroxyapatite (HA). The cytotoxicity assessments showed the as-extruded β-Ca3(PO4)2/Mg-Zn composite aged for 72h was harmless to L-929 cells. These results suggested that the β-Ca3(PO4)2/Mg-Zn composites prepared by powder metallurgy were promising to be used for bone tissue engineering.

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.

In general, the Al-Mg-Mn-Sc alloys are not strengthened by heat treatment. Rather, hot rolling process renders a great influence on subsequent performance. Herein, the recrystallization annealing is carried out during the hot rolling process of alloy plates, and microstructural and texture evolution is systematically studied. The results reveal that the grain size of alloy significantly decreased from 169.226 µm to 24.4885 µm after recrystallization annealing and hot rolling. Also, the obvious dynamic recrystallization and a large number of dislocation walls are observed in the grains, which are conducive to the continuous hot machining of Al-Mg-Mn-Sc alloys with large deformation. In addition, the texture strength of alloy plate is increased due to recrystallization and grain orientation is significantly altered, where the grain orientation changed from 〈1 1 1〉 to 〈1 0 1〉 direction.

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-Mg17Al12 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 Mg2Sn phases along the grain boundaries and to suppress the precipitate of coarse β-Mg17Al12 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.

The microstructure, texture, tensile strength, and corrosion behavior of Al–Mg–Sc–Zr alloy at different annealing temperatures were investigated using SEM, TEM, XRD, and dual potentiostat techniques. Results show that in the process of alloy homogenization annealing, the Al–Mg–Sc–Zr alloy is able to precipitate spherical particles of Al3(Sc, Zr) with a diameter of about 10 nm and a lattice constant of 0.41 nm, which can pin dislocation, hinder grain boundary movement, and suppress recrystallization. Moreover, the dislocations move to the grain boundaries during the annealing process, leading to the formation of dislocation walls. Remarkably, the sub-crystals are also formed as the grain boundaries parallel to {101}, and move to become parallel to {111}. The texture mainly consists of copper, brass, S, and R, and only a small amount of recrystallization cube texture. Furthermore, under the influence of the microstructure and texture, the strength of the alloy decreases, the plasticity increases, and the corrosion resistance first increases and then decreases. The optimal mechanical properties and corrosion resistance were obtained when the annealing was done at 300 °C for 1 h.