ISSN: 1003-6326
CN: 43-1239/TG
CODEN: TNMCEW

Vol. 15    No. 1    February 2005

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Microstructure and mechanical properties of magnesium alloy prepared by lost foam casting
TIAN Xue-feng(田学锋), FAN Zi-tian(樊自田), HUANG Nai-yu(黄乃瑜),
WU He-bao(吴和保), DONG Xuan-pu(董选普)
(State Key Laboratory of Plastic Forming and Die & Mould Technology,
College of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
)
Abstract: The microstructure and mechanical properties of AZ91 alloy prepared by lost foam casting (LFC) and various heat treatments have been investigated.  The microstructure of the AZ91 alloy via LFC consists of dominant α-Mg and β-Mg17Al12 as well as a new phase Al32Mn25 with size of about 5-50μm, which has not been detected in AZ91 alloy prepared by other casting processes.  The tests demonstrate that the ascast mechanical properties are higher than those of sand gravity casting because of chilling and cushioning effect of foam pattern during the mould filling.  The solution kinetics and the aging processes at different temperatures were also investigated by hardness and electrical resistivity measurements.  The kinetics of aging are faster at the high temperature due to enhanced diffusion of atoms in the matrix, so the hardness peak at 380℃ occurs after 10h; while at the lower aging temperature(150℃), the peak is not reached in the time(24h) considered.
Key words: magnesium alloy; lost foam casting; mechanical property; microstructure
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
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