Hydrogen evolution reaction is inevitable during the corrosion of Mg alloys.The effect of hydrogen on the corrosion behavior of the Mg-2Zn and Mg-5Zn alloys is investigated by charging hydrogen treatment.The surface m...Hydrogen evolution reaction is inevitable during the corrosion of Mg alloys.The effect of hydrogen on the corrosion behavior of the Mg-2Zn and Mg-5Zn alloys is investigated by charging hydrogen treatment.The surface morphologies of the samples after charging hydrogen were observed using a scanning electron microscopy(SEM)and the corrosion resistance was evaluated by polarization curves.It is found that there are oxide films formed on the surface of the charged hydrogen samples.The low hydrogen evolution rate is helpful to improve the corrosion resistance of Mg alloys,while the high hydrogen evolution rate can increases the defects in the films and further deteriorates their protection ability.Also,the charging hydrogen effect is greatly associated with the microstructure of Mg substrate.展开更多
通过自制的"T"字形模具研究了不同配比的Zn对Mg-xZn-0.5Y-0.5Zr(x=1.5,2.5,3.5 and 4.5(%,质量分数))系合金热裂敏感性的影响。通过对"T"型试样热节处宏观热裂纹的观察以及石蜡渗透法测定的裂纹的体积来表征其热裂...通过自制的"T"字形模具研究了不同配比的Zn对Mg-xZn-0.5Y-0.5Zr(x=1.5,2.5,3.5 and 4.5(%,质量分数))系合金热裂敏感性的影响。通过对"T"型试样热节处宏观热裂纹的观察以及石蜡渗透法测定的裂纹的体积来表征其热裂倾向性大小。此外采用扫描电镜(SEM)进行合金的组织形貌微观分析和裂纹自由断口表面观察,并利用X射线衍射(XRD)及投射电镜(TEM)等实验手段对其进行物相分析,确定其低熔点相主要组成,进而研究对热裂缺陷的影响。整个熔炼浇注过程利用A/D数模转换器对凝固过程进行了温度-应力采集。结果表明,MgxZn-0.5Y-0.5Zr合金的主要相组成为α-Mg,W相(Mg3Zn3Y2)及I相(Mg3Zn6Y),随着Zn含量从1.5%增加到4.5%,低熔点析出相含量明显增多,提高了枝晶间残余液相的补缩能力,有效的防止了裂纹的萌生和扩展,当Zn含量较低时,液膜理论和凝固收缩补偿理论是诠释热裂纹萌生的主要理论基础。随着Zn含量的增加,残余液相的充分补偿,桥接理论是热裂形成的主要机理。此系合金热裂敏感性由大到小顺序为Mg-1.5Zn-0.5Y-0.5Zr,Mg-2.5Zn-0.5Y-0.5Zr,Mg-3.5Zn-0.5Y-0.5Zr,Mg-4.5Zn-0.5Y-0.5Zr。展开更多
This study aims to investigate the addition of Zn on the corrosion property and cytocompatibility of Mg- 2Gd-xZn (x = 0, 3, 4 and 5;wt%) alloys, which were prepared by gravity permanent mold casting and solution treat...This study aims to investigate the addition of Zn on the corrosion property and cytocompatibility of Mg- 2Gd-xZn (x = 0, 3, 4 and 5;wt%) alloys, which were prepared by gravity permanent mold casting and solution treatment, respectively. The results show that the intermetallic phases of these ternary alloys are mainly composed of Mg12GdZn and Mg3GdZn3. The content of secondary phases as well as the grain size is greatly dependent on the Zn addition. Compared to the binary Mg- 2Gd alloy, the corrosion resistance of the most ternary alloys is significantly improved. Furthermore, the in vitro cell culture study demonstrates the potential cytocompatibility of the developed ternary alloys. It indicates that a series of Mg-2Gd-xZn (x = 0, 3, 4 and 5;wt%) with medically acceptable corrosion rate are developed and show great potential use as a new type of biodegradable implants.展开更多
基金Financial supports from China Scholarship Council and Helmholtz Association of German Research Centers scholarship(No.2010821213) for Wang’s Ph D study in Helmholtz-Zentrum Geesthacht(HZG) are gratefully acknowledged
基金Thanks for the financial support by Korea Institute of Materials Science,National Key Basic Research Program of China(No.2013CB632205)the National Natural Science Foundation of China(No.51471174).
文摘Hydrogen evolution reaction is inevitable during the corrosion of Mg alloys.The effect of hydrogen on the corrosion behavior of the Mg-2Zn and Mg-5Zn alloys is investigated by charging hydrogen treatment.The surface morphologies of the samples after charging hydrogen were observed using a scanning electron microscopy(SEM)and the corrosion resistance was evaluated by polarization curves.It is found that there are oxide films formed on the surface of the charged hydrogen samples.The low hydrogen evolution rate is helpful to improve the corrosion resistance of Mg alloys,while the high hydrogen evolution rate can increases the defects in the films and further deteriorates their protection ability.Also,the charging hydrogen effect is greatly associated with the microstructure of Mg substrate.
文摘通过自制的"T"字形模具研究了不同配比的Zn对Mg-xZn-0.5Y-0.5Zr(x=1.5,2.5,3.5 and 4.5(%,质量分数))系合金热裂敏感性的影响。通过对"T"型试样热节处宏观热裂纹的观察以及石蜡渗透法测定的裂纹的体积来表征其热裂倾向性大小。此外采用扫描电镜(SEM)进行合金的组织形貌微观分析和裂纹自由断口表面观察,并利用X射线衍射(XRD)及投射电镜(TEM)等实验手段对其进行物相分析,确定其低熔点相主要组成,进而研究对热裂缺陷的影响。整个熔炼浇注过程利用A/D数模转换器对凝固过程进行了温度-应力采集。结果表明,MgxZn-0.5Y-0.5Zr合金的主要相组成为α-Mg,W相(Mg3Zn3Y2)及I相(Mg3Zn6Y),随着Zn含量从1.5%增加到4.5%,低熔点析出相含量明显增多,提高了枝晶间残余液相的补缩能力,有效的防止了裂纹的萌生和扩展,当Zn含量较低时,液膜理论和凝固收缩补偿理论是诠释热裂纹萌生的主要理论基础。随着Zn含量的增加,残余液相的充分补偿,桥接理论是热裂形成的主要机理。此系合金热裂敏感性由大到小顺序为Mg-1.5Zn-0.5Y-0.5Zr,Mg-2.5Zn-0.5Y-0.5Zr,Mg-3.5Zn-0.5Y-0.5Zr,Mg-4.5Zn-0.5Y-0.5Zr。
基金financially supported by the National Natural Science Foundation of China (Nos. 31300808 and 31400815)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi (No. 201417)the Natural Science Foundation of Shanxi Province (No. 2013021011-1)
文摘This study aims to investigate the addition of Zn on the corrosion property and cytocompatibility of Mg- 2Gd-xZn (x = 0, 3, 4 and 5;wt%) alloys, which were prepared by gravity permanent mold casting and solution treatment, respectively. The results show that the intermetallic phases of these ternary alloys are mainly composed of Mg12GdZn and Mg3GdZn3. The content of secondary phases as well as the grain size is greatly dependent on the Zn addition. Compared to the binary Mg- 2Gd alloy, the corrosion resistance of the most ternary alloys is significantly improved. Furthermore, the in vitro cell culture study demonstrates the potential cytocompatibility of the developed ternary alloys. It indicates that a series of Mg-2Gd-xZn (x = 0, 3, 4 and 5;wt%) with medically acceptable corrosion rate are developed and show great potential use as a new type of biodegradable implants.
