Biomedical Engineering Reference
In-Depth Information
Fig. 2. Optical microstructure of as-cast Mg-Zn alloys (a) Mg-1.0Zn; (b) Mg-2.0Zn; (c) Mg-
3.0Zn; (d) Mg-4.0Zn; (e) Mg-5.0Zn; (f) Mg-6.0Zn
3.1.2 The effects of Ca content on phase compositions and microstructures of the
as-cast alloys
In present study, the mechanical properties show that when Zn content is 4wt. %, the Mg-
xZn has good mechanical properties. Thus, the initial content of Zn designs as 4.0wt. % and
then changed the content of Ca to study the effects on phase compositions and
microstructures .The chemical compositions of the Mg-4.0 Zn-x Ca alloy obtained by ICP-
AES were listed in Table 3. X-ray diffraction (XRD) analyses were used to investigate the
existing phases in the Mg-4.0Zn-xCa alloys, and the results were shown in Fig.3. The results
showed that α-Mg and MgZn phases were detected in the Mg-4.0 Zn alloy, and it also
indicated that the diffraction peaks from the MgZn phase were very weak and that of the
Mg were strong. There was no obvious change in diffraction peak when 0.2 wt. % Ca and
0.5wt. % Ca was added into the Mg-4.0 Zn alloy. With the Ca concentration increased to 1.5
wt. %, Ca
2
Mg
6
Zn
3
phases began to be detected in Mg-4.0 Zn-xCa. When the Ca
concentration increased to 2.0 wt. %, Mg
2
Ca, and Ca
2
Mg
5
Zn
13
phases began to be detected in
the alloy.
Chemical composition (wt.%)
Materials
Al
Zn
Mn
Si
Fe
Ca
Mg
Mg-4.0Zn
0.023
3.926
0.058
0.031
0.004
0.007
Balance
Mg-4.0Zn-0.2Ca
0.033
1.852
0.030
0.039
0.007
0.180
Balance
Mg-4.0Zn-0.5Ca
0.029
2.732
0.022
0.036
0.007
0.452
Balance
Mg-4.0Zn-1.0Ca
0.019
3.925
0.021
0.032
0.008
0.915
Balance
Mg-4.0Zn-1.5Ca
0.027
5.223
0.031
0.034
0.009
1.635
Balance
Mg-4.0Zn-2.0Ca
0.024
5.977
0.019
0.033
0.012
2.158
Balance
Table 2. Chemical composition of the as-cast Mg-4.0Zn-xCa alloys