| Abstract |
| Microstructure and fracture behavior of the squeeze cast Mg-Al-Zn-Si alloys (AZ91-Si, AZ51-Si, AZ51 Si-Ca) have been investigated in the present study. To clarify the fracture behavior, in-situ fracture test and fractographic observation were conducted. The higher Al content promoted formation of the polygonal type Mg2Si, but resulting in reduction of the ductility due to increase in amount of Mg17Al12 and to presence of coarse Mg2Si. The lower Al content favored formation of the chinese script type Mg2Si which promoted the brittle fracture along the Mg2Si/matrix interface. AZ51-Si alloy had a higher ductility than AZ91-Si, because a number of slip lines were developed inside grains and cracks were blunted by matrix. The addition of Ca eliminated the chinese script type Mg2Si. Instead, fine Mg2Si particles were present in a polygonal shape, resulting in improvement of mechanical properties. |
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| Key Words |
| Polygonal type, Chinese script type, Mg2Si, Al content, Ca effect, Fracture behavior, Slip Line |
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