Semisolid Structure and Parameters for A360 Aluminum Alloy Prepared by Mechanical Stirring

Semisolid metal processing uses solid–liquid slurries containing fine and globular solid particles uniformly distributed in a liquid matrix, which can be handled as a solid and flow like a liquid. In the recent years, many methods have been introduced for the production of semisolid slurries since it is scientifically sound and industrially viable with such preferred microstructures called thixotropic microstructures as feedstock materials. One such process that needs very low equipment investment and running costs is the cooling slope. In this research by using a mechanical stirrer slurry maker constructed by the authors, the effects of mechanical stirring parameters such as: stirring time, stirring temperature and stirring Speed on micro-structure and mechanical properties of A360 aluminum alloy in semi-solid forming, are investigated. It is determined that mold temperature and holding time of part in temperature of 580ºC have a great effect on micro-structure and mechanical properties(stirring temperature of 585ºC, stirring time of 20 minutes and stirring speed of 425 RPM). By optimizing the forming parameters, dendrite microstructure changes to globular and mechanical properties improves. This is because of breaking and globularzing dendrites of primary α-AL.

Authors:

• MM.Kaykha
• A. Kamarei
• M. Safari
• V. Arbabi

Keywords:

• Semi-Solid Forming
• Mechanical properties
• Shear Rate.

References:

[1] Seijiro M., Yasunori H., Ken.Ichiro M., "Application of resistance
heating technique to mushy state forming of aluminum alloy", Journal of
materials processing technology, 125-126, (2002), 477-482.
[2] Lee B.S., Joe D.H., Kim M.H., "Extrusion behavior of Al-Cu Alloy in
the semi solid state", Materials science and engineering, A 402, (2005),
170-176.
[3] Vogel Y., Zhang K., "The formation of rosette phase structural evolution
during the reheating and semi solid casting of AlSi7Mg Alloy", Journal
of materials processing technology, 137, (2003), 195-200.
[4] Hellawel, T., Stjohn D.H., Steiberg.T,"The shear behavior of partially
solidified Al-Si-Cu alloys", Materials science and engineering, A286,
(2000), 18-29.
[5] Z., Fan, "Semi Solid Motel Processing", Proceedings of Ninth North
American Manufacturing Research Conference, (1981), 140-144.
[6] Haghayaghi R.,Zoqui E.J.,Halvaee A., "An Investigation on Semi Solis
Al-7Si-0.3Mg Alloy Produced By Mechanical Stirring", Journal of
materials processing technology, 169, (2005), 382-387.
[7] Barabazon D.,Browne D.J., Carr A.J., "Mechanical Stir casting of
aluminum alloy from the mushy state: process, microstructure and
mechanical properties.", Materials science and engineerin,A.236, (2002),
370-381