Significant grain refinement was achieved in rare earth (RE) containing aeronautic magnesium alloy ZE41A through equal-channel angular pressing (ECAP) using rotary die at 603 K. Influence of ECAP pass number on its mi...Significant grain refinement was achieved in rare earth (RE) containing aeronautic magnesium alloy ZE41A through equal-channel angular pressing (ECAP) using rotary die at 603 K. Influence of ECAP pass number on its microstructure change and corrosion behavior was investigated by optical microscope (OM)/scanning electron microscope (SEM) observation and potentiostatic polarization tests in aqueous solution of NaCl, respectively. The results showed that ultrafine equiaxial grains (about 2.5 μm) were obtained over 16 passes due to plastic-induced grain refinement accommodated by dynamic recrystallization. The lower corrosion current density and nobler corrosion potential correlated with large number of pressing passes were attributed to the low tendency toward localized corrosion with broken secondary phase after homogenization on ultrafine-grained Mg matrix. The multi-pass ECAP method made the ZE41A aeronautic magnesium alloy more attractive since severe plastic deformation may significantly improve its corrosion resistance besides superior mechanical properties.展开更多
Two kinds of Mg-Zn-Mn-Ca alloys with and without cerium were designed and fabricated. In-vitro degradation tests and electrochemical evaluations were carried out to compare their biocorrosion behavior in Hank＇s solut...Two kinds of Mg-Zn-Mn-Ca alloys with and without cerium were designed and fabricated. In-vitro degradation tests and electrochemical evaluations were carried out to compare their biocorrosion behavior in Hank＇s solution at 37 oC. After adding cerium, the continuous network distributed Ca2Mg6Zn3 phases in Mg-2Zn-0.5Mn-1Ca alloy（Alloy I） were separated due to the emerging non-continuously distributed Mg2 Ca phase and Mg12 Ce Zn phase. This change led to corrosion acceleration of Mg matrix at the initial stage but also sped up the formation of compact corrosion products for Mg-2Zn-0.5Mn-1Ca-1.5Ce alloy（Alloy II）, and therefore enhanced its biocorrosion resistance. Cerium containing Alloy II has the potential to be used as future biomaterials.展开更多
基金Project supported by the Japan Society for the Promotion of Science (JSPS) for UFG ZE41A FabricationQing Lan Project (Jiangsu,China)
文摘Significant grain refinement was achieved in rare earth (RE) containing aeronautic magnesium alloy ZE41A through equal-channel angular pressing (ECAP) using rotary die at 603 K. Influence of ECAP pass number on its microstructure change and corrosion behavior was investigated by optical microscope (OM)/scanning electron microscope (SEM) observation and potentiostatic polarization tests in aqueous solution of NaCl, respectively. The results showed that ultrafine equiaxial grains (about 2.5 μm) were obtained over 16 passes due to plastic-induced grain refinement accommodated by dynamic recrystallization. The lower corrosion current density and nobler corrosion potential correlated with large number of pressing passes were attributed to the low tendency toward localized corrosion with broken secondary phase after homogenization on ultrafine-grained Mg matrix. The multi-pass ECAP method made the ZE41A aeronautic magnesium alloy more attractive since severe plastic deformation may significantly improve its corrosion resistance besides superior mechanical properties.
基金supported by National Natural Science Foundation of China(51141002)Natural Science Foundation of Jiangsu Province(BK2011249)the Fundamental Research Funds for the Central Universities of China(2011B08214)
文摘Two kinds of Mg-Zn-Mn-Ca alloys with and without cerium were designed and fabricated. In-vitro degradation tests and electrochemical evaluations were carried out to compare their biocorrosion behavior in Hank＇s solution at 37 oC. After adding cerium, the continuous network distributed Ca2Mg6Zn3 phases in Mg-2Zn-0.5Mn-1Ca alloy（Alloy I） were separated due to the emerging non-continuously distributed Mg2 Ca phase and Mg12 Ce Zn phase. This change led to corrosion acceleration of Mg matrix at the initial stage but also sped up the formation of compact corrosion products for Mg-2Zn-0.5Mn-1Ca-1.5Ce alloy（Alloy II）, and therefore enhanced its biocorrosion resistance. Cerium containing Alloy II has the potential to be used as future biomaterials.
