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

Abstract

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°C/s, grain size was the smallest (30.57 µm). The second phases included lamellar LPSO, block-like Mg₃ (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°C/s, the mechanical properties were the best, and UTS, YS and elongation were 228.2 MPa, 158.2 MPa and 8.8%, respectively.

KEYWORDS:

• Cooling rate
• solidification behaviour
• microstructure evolution
• mechanical properties

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors gratefully acknowledge the financial support from the Heilongjiang Province Natural Science Foundation (No. E2018045).