The Solidification Behavior of AA2618 Aluminum Alloy and the Influence of Cooling Rate
Yulin Liu,
Ming Liu,
Lei Luo,
Jijie Wang,
Chunzhong Liu
Affiliations
Yulin Liu
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
Ming Liu
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
Lei Luo
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
Jijie Wang
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
Chunzhong Liu
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
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.