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Mechanical properties of cast Al-7Si-0.3Mg (LM 25/356) alloy

1998; Taylor & Francis; Volume: 11; Issue: 2 Linguagem: Inglês

10.1080/13640461.1998.11819265

1743-1336

M. Ravi, U.T.S. Pillai, B.C. Pai, A. D. Damodaran, E. S. Dwarakadasa,

Microstructure and mechanical properties

The effect of Mg (up to 0.5%) and Fe content (up to 0.6%), melt holding time, hydrogen content, modification (by Sr and mischmetal (MM)), pouring temperature, grain refinement (by Zr and TiB) and cooling rate on the mechanical properties and microstructure of cast Al-7Si-0.3Mg (LM 25/356) alloy has been investigated. Structure property correlation of this alloy was attempted using optical microsctructure, fractrographs, X-ray diffraction, EDAX and quantitative metallography. The mechanical properties of the alloy were found to increase with increased Mg content. Higher Fe content, higher hydrogen content, low as well as higher pouring temperature and low cooling rate contribute to lower mechanical properties. The addition of 1% mischmetal (MM) was found to refine the structure, partially modify the eutectic silicon and form fine intermetallic compounds of La, Ce with Al, Si, Fe, and Mg, which improve the mechanical properties of the alloy; whereas Sr addition improves the properties by complete modification of the eutectic silicon.