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Adjusting the Si Phase and Forming Nanoprecipitation to Improve the Mechanical Properties of Al–Si–Cu–Mg Alloy by Heat Treatment
Author(s) -
Hao Jianfei,
Yu Baoyi,
Bian Jiancong,
Liu Jinmin,
Sun Wanting,
Shi Yuanji,
Li Runxia
Publication year - 2021
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.202001526
Subject(s) - materials science , alloy , ultimate tensile strength , microstructure , phase (matter) , dislocation , casting , metallurgy , composite material , precipitation , precipitation hardening , physics , organic chemistry , meteorology , chemistry
To adjust the morphology of the Si phase and improve the mechanical properties of Al–Si–Cu–Mg alloy formed by semisolid squeeze casting, the effects of solution time on microstructure evolution and mechanical properties are systematically studied. Results show that spheroidization occurs in the Si phase, and the content of Cu in the matrix increases simultaneously after solution treatment at 525 °C for 1 h. As solution time increases to 8 h, the content of Cu in the matrix increases from 1.15% to 1.41% and the dislocation density decreases. After an aging treatment at 180 °C for 12 h, the β′, θ′, and Q′ phases precipitate. After heat treatment, the alloy strength value shows a “double peak” phenomenon. After a 1 h solution treatment, the tensile strength of the alloy reaches the first peak, which is mainly ascribed to the large dislocation density induced by the semisolid squeeze casting process. When the solution time is 8 h, the tensile strength of the alloy is 323 MPa and the tensile strength reaches the second peak, which is ascribed to the rounding of the Si phase and the strengthening effects of fine precipitates.