The Solidification Behavior of AA2618 Aluminum Alloy and the Influence of Cooling Rate

Materials

Yulin Liu¹  Ming Liu²  Lei Luo²  Jijie Wang²  Chunzhong Liu² 

[1] Liaoning Provincial Key Laboratory of Light Alloys and Processing Technology, School of Materials Science and Engineering, Shenyang Aerospace University, 37 Daoyi Avenue S., Shenyang 110136, China;

关键词: aluminum alloy;    AA2618 alloy;    solidification behavior;    near-rapid cooling;    microstructure;   

DOI  :  10.3390/ma7127875

来源: mdpi

【 摘 要 】

In AA2618 aluminum alloy, the iron- and nickel-rich intermetallics formed during solidification are of great effect on the mechanical properties of the alloy at both room temperature and elevated temperatures. However, the solidification behavior of the alloy and the formation mechanism of the intermetallics during solidification of the alloy are not clear. This research fills the gap and contributes to understanding the intermetallic of the alloy. The results showed that cooling rate was of great influence on the formation of the intermetallics. Under the condition of slow cooling, the as-cast microstructures of the alloy were complex with many coarse eutectic compounds including Al₉FeNi, Al₇(CuNi)₅, Si, Al₂Cu and Al₂CuMg. The phase Al₉FeNi was the dominant intermetallic compound, which precipitated at the earlier stage of the solidification by eutectic reaction L → α-Al + Al₉FeNi. Increasing the cooling rate would suppress the formation of the coarse eutectic intermetallics. Under the condition of near-rapid cooling, the as-cast microstructures of the alloy consisted of metastable intermetallics Al₉FeNi and Al₂Cu; the equilibrium eutectic compounds were suppressed. This research concluded that intermetallics could be refined to a great extent by near-rapid cooling.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.