Compressive and Corrosion Properties of Lotus-Type Porous Mg-Mn Alloys Fabricated by Unidirectional Solidification

摘要

Lotus-type porous Mg-Mn alloys were fabricated by solid-gas eutectic unidirectional solidification (the Gasar process) by controlling and optimizing the process parameters. The microstructures, compressive properties and corrosion properties in a simulated body fluid solution were investigated. Porous pure Mg was prepared with a preferentially oriented (11 (2) over bar2) plane, whereas the Mg-2 wt pct Mn alloy showed a preferentially oriented (10 (1) over bar3) plane. Mn addition refined the grains, improved the Mn precipitates, activated the {10 (1) over bar2} twin at the end of the pores and increased the compressive strength from 64 MPa for pure Mg to 74 MPa for 1 wt pctMn and 80 MPa for 2 wt pct Mn. Electrochemical tests showed that 2 wt pct Mn addition could decrease the corrosion current from 1.84 x 10(-3) to 4.22 x 10(-4) A cm(-2). Immersion tests suggest that 2 wt pct Mn addition reduced the sample mass loss, which indicated a better corrosion performance, and exhibited a smaller decrease in compressive strength compared with that of the porous pure Mg. This work shows that the Gasar technique can be a promising fabrication method to prepare lotus-type porous Mg-Mn alloys which are more attractive for application in degradable biomaterials engineering.