Effect of cooling rate on microstructure and mechanical properties of Mg-9Gd-4Y-1Zn-1Al alloy

In this paper, the effect of cooling rate on solidification behaviour, microstructure evolution and mechanical properties of Al-refined Mg-9Gd-4Y-1Zn was studied. As cooling rate decreased, grain size increased and when cooling rate was 32.5 degrees C/s, grain size was the smallest (30.57 mu m). The second phases included lamellar LPSO, block-like Mg-3 (Zn, RE), granular Al2RE and acicular Al2RE. As cooling rate decreased, the content of granular Al2RE increased, while that of other phases decreased. As cooling rate decreased, ultimate tensile strength (UTS), yield strength (YS) and elongation all decreased. When cooling rate was 32.5 degrees C/s, the mechanical properties were the best, and UTS, YS and elongation were 228.2 MPa, 158.2 MPa and 8.8%, respectively.

Automated summary

The effect of cooling rate on solidification behaviour, microstructure evolution and mechanical properties of Al-refined Mg-9Gd-4Y-1Zn was investigated in this study. A decrease in cooling rate led to an increase in grain size and the smallest grain size (30.57 µm) was observed at a cooling rate of 32.5 degrees C/s. Different phases including lamellar LPSO, block-like Mg-3 (Zn, RE), granular Al2RE and acicular Al2RE were identified. The content of granular Al2RE increased with a decrease in cooling rate, while the content of other phases decreased. The mechanical properties, including ultimate tensile strength, yield strength and elongation, decreased as the cooling rate decreased. The best mechanical properties were achieved at a cooling rate of 32.5 degrees C/s, with values of 228.2 MPa, 158.2 MPa, and 8.8% for UTS, YS, and elongation, respectively.