Effect of solution treatment on microstructure and mechanical properties of Al-12Si-4Cu-2Ni-0.8Mg-0.2Gd alloy was investigated. Results show the Si particles become stable and more intermetallic compounds dissolve in the matrix after solution treatment at 500 ℃ for 2 h followed by 540 ℃ for 3 h (T4). The skeleton-like Al3CuNi develops into two parts in the T4 alloy: one is Al3CuNi which has the framework shape; the other is intermetallics including the Al3CuNi (size: 5-10 μm) and AlSiCuNiGd phases (size: ≤5 μm) with complex structure. Adding 0.2％ Gd can improve the mechanical properties of the alloys after two-step solution treatment (500 ℃/2 h followed by 540 ℃/3 h), the hardness of the alloy increases from 130.9 HV to 135.8 HV compared with the alloy with one-step solution treatment (500 ℃/2 h), the engineering strength increases from 335.45 MPa to 352.03 MPa and the fracture engineering strain increases from 1.44％ to 1.67％.

Yu-dong Sui;Ye-hua Jiang;Qu-dong Wang

School of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China;National Engineering Research Center of Light Alloys Net Forming and State Key Laboratory of Metal Matrix Composite,Shanghai Jiao Tong University,Shanghai 200240,China

中国铸造

[1]Yu-dong Sui;Ye-hua Jiang;Qu-dong Wang-.Effect of solution treatment on microstructure and mechanical properties of as-cast Al-12Si-4Cu-2Ni-0.8Mg-0.2Gd alloy)[J].中国铸造,2022(03):238-244

Al3CuNi,AlSiCuNiGd

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