Rheocasting an Engine Mounting Bracket in Commercial 7075

Abstract:

Wrought aluminium alloys are prone to hot tearing when cast into near-net shapes. This problem can be overcome by the novel casting technique of rheo-processing combined with high pressure die casting. An industrial engine mounting bracket is produced by rheo-process commercial 7075 with the patented CSIR-RCS and subsequent high pressure die casting. Section thickness changes and constraining geometry make this a difficult component to rheocast. X-ray radiography is used to evaluate hot tearing over the component and is correlated to piston injection shot profile velocities. Gross hot tearing is significantly reduced by a higher injection velocity but turbulent flow entraps air. Faster injection allows more time for flow before final solidification.

References

[1] S. Lin, C. Aliravci and M.O. Pekguleryuz: Metall. Mat. Trans. A 38 (2007), p.1056.

[2] D.G. Eskin, Suyitno, and L. Katgerman: Prog Mater Sci. 49 (2004), p.629.

[3] Z. Fan, X. Fang and S. Ji: Mater. Sci. Eng. A 412 (2005), p.298.

[4] R. Bruwer, J.D. Wilkins, L.H. Ivanchev, P. Rossouw and O.F.R.A. Damm: US Patent 7368690. (2008).

[5] H. Möller, G. Govender, W.E. Stumpf and P.C. Pistorius: Int. J. Cast Metals Res. 23 (2010), p.37.

[6] E.P. Masuku, H. Möller, R. Knutsen, L. Ivanchev and G. Govender: Mater. Sci. Forum Vol. 618-619 (2009), p.353.

DOI: 10.4028/www.scientific.net/msf.618-619.353

[7] U.A. Curle: Trans. Nonferrous Met. Soc. China 20 (2010), p.1719.

[8] U.A. Curle and G. Govender: Trans. Nonferrous Met. Soc. China 20 (2010), p. s832.

[9] U.A. Curle and L. Ivanchev: Trans. Nonferrous Met. Soc. China 20 (2010), p. s852.

[10] U.A. Curle, H. Möller and J.D. Wilkins: Scripta Mater. 64 (2011), p.479.

[11] U.A. Curle, J.D. Wilkins and G. Govender: Advances Mater. Sci. Eng. (2011), Article ID 195406. doi: 10. 1155/2011/195406.