Performance and Fundamental Differences between Rheocast and High-Pressure Vacuum Die Cast Al-Si-Mg Alloys

Abstract:

The Al-Si-Mg family is the preferred group of casting alloys due to their excellent castability, good mechanical properties and corrosion resistance. The ENAC-AlSi7Mg0.3 (A356) alloy has been used for decades to produce structural parts such as automotive wheels or suspension parts. However, this alloy cannot be used for high pressure die casting (HPDC) due to die soldering issues. Casting parameters in rheocasting differs greatly from those in HPDC. The lower injection temperature and lower intensification pressure reduce the reactivity between the mould and the aluminium. This lower interaction allows the injection of permanent mould alloys using HPDC. The objective of this work is to compare current structural alloys with rheocasting. A wide range of alloys in the Al-Si-Mg (-Mn) family were cast using the RheometalTM semi-solid technology in addition to ENAC-AlSi7Mg0.3 (A356) used as a comparison basis. Firstly, it was proven that ENAC-AlSi7Mg0.3 (A356) can successfully be cast using rheocast HPDC. Secondly, the impact of magnesium and manganese were studied. Magnesium has a great impact on strength while manganese can further improve the strength by controlling the iron phase morphology. This work proves that various types of alloys can be cast using rheocast HPDC.

• Periodical: Solid State Phenomena (Volume 348)
• Pages: 75-82
• DOI: https://doi.org/10.4028/p-p5sK4z
• Online since: August 2023
• Authors: Francis Breton*, Jerome Fourmann
• Keywords: Al-Si-Mg (-Mn), High Pressure Die Casting, Rheocast

References

[1] J.G. Kaufman, E.L. Rooy, Aluminum Alloy Castings: Properties, Processes, and Applications, ASM International, chapter 2

[2] G.K. Sigworth, F. DeHart, Recent Developments in the High Strength Aluminum-Copper Casting Alloy 206, American Foundry Society (2003)

[3] A.A. Luo, A.K. Sachdev, B.R. Powell, Advanced casting technologies for lightweight automotive applications, China Foundry vol. 7 No. 4

[4] Z. Brown, P. Burton, High Integrity Die Cast Aluminum Body Components, SAE Transactions Vol. 116, Section 5: Journal of Materials and Manufacturing (2007), pp.139-143

DOI: 10.4271/2007-01-0460

[5] F. Breton, J. Fourmann, Alloys with High Strength and Ductility for High Pressure Vacuum Die Casting in Automotive Body Structure Applications: Impact of Heat Treatment on Mechanical Properties, North American Die Casting Association, Die Casting Congress & Tabletop 2016.

DOI: 10.31399/asm.hb.v15.a0005276

[6] M. Kohlhepp, P. J. Uggowitzer, M. Hummel, H. W. Höppel, Formation of Die Soldering and the Influence of Alloying Elements on the Intermetallic Interface, Materials 2021, 14, 1580.

DOI: 10.3390/ma14071580

[7] M. M. Makhlouf, D. Apelian, Casting Characteristics of Aluminum Die Casting Alloys, The Advanced Casting Research Center, Worcester Polytechnic Institute, DOE/ID--13716

DOI: 10.2172/792701

[8] I. Belov et al., Effect of Fillets on Heat Transfer in a Rheocast Aluminium Heatsink, 2016.

[9] J. Langlais, N. Andrade, X.G. Chen, A. Lemieux, "The Wrought Aluminium Alloy AA6061 Made Suitable for Semi-Solid Forming", Cast Expo (2008)

DOI: 10.4028/www.scientific.net/ssp.141-143.511

[10] F. Breton, New High Strength 3xx Series Alloy Case Study: Automotive Wheel Weight Reduction, American Foundry Society (2019)

[11] Q.G. Wang, C.J. Davidson, J.R. Griffiths, P.N. Crepeau, Oxide Films, Pores and the Fatigue Lives of Cast Aluminium Alloys, Metallurgical and Materials Transactions B, Volume 37B, December (2006)

DOI: 10.1007/bf02735010

[12] J.F. Major: AFS Trans., 1997, vol. 105, pp.901-06

[13] J. Langlais, A. Lemieux, N. Andrade, D. Bouchard, Impact of semi-solid process parameters on the microstructure, morphology and mechanical properties of A356 alloy, COM (2006)