Effect of Thickness and Permeability of Ceramic Shell Mould on In Situ Melted AZ91D Investment Casting

Abstract:

The influence of ceramic shell mould thickness and permeability on investment casting of AZ91D alloy using in-situ melting technique was investigated. AZ91D granules together with melting flux were charged into two different moulds having different thicknesses and four various permeabilities; then were heated at 650°C in order to be melted. Visual inspection and scanning electron microscopes were used to characterise the surface quality of cast samples. Thermal analysis was employed to further analyse the effect of mould thickness on cooling and solidification behaviour of molten metal. The findings of this research showed that thinner mould provided higher solidification rate, which is believed to favour in-situ melting enhancement. It enabled melting of the granules at the investigated temperature resulted in suppressing mould-metal reaction and producing cast samples with good surface quality. The results also showed that the permeability of shell mould was ineffective in suppressing mould-metal reaction.

• Periodical: Applied Mechanics and Materials (Volumes 465-466)
• Pages: 1087-1092
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.465-466.1087
• Online since: December 2013
• Authors: Hassan Jafari*, Mohd Hasbullah Idris, Ali Ourdjini
• Keywords: AZ91D, In Situ Melting, Investment Casting, Permeability, Shell Mould, Thickness

References

[1] S. Lun Sin, D. Dubé, R. Tremblay, An investigation on microstructural and mechanical properties of solid mould investment casting of AZ91D magnesium alloy, Mater. Charact. 59 (2008) 178-187.

DOI: 10.1016/j.matchar.2007.04.026

[2] S. Lun Sin, D. Dubé, R. Tremblay, Interfacial reactions between AZ91D magnesium alloy and plaster mould material during investment casting. Mater. Sci. Tech. 22 (2006) 1456-1463.

DOI: 10.1179/174328406x148804

[3] C. Cingi, J. Vainola, J. Orkas, Role of oxygen in mould-metal reactions in investment casting of magnesium alloy AZ91E, Int. Foundry Res. 59 (2007) 18-27.

[4] M.H. Idris, A. Ourdjini, E. Hamzah, A.J. Clegg, Suppression of mould-metal reactions during investment casting, in: K.U. Kainer (ed), Magnesium Alloys and their Applications, Wiley InterScience Publisher, 2000, pp.628-634.

DOI: 10.1002/3527607552.ch99

[5] G.Y. Yang, W.Q. Jie, Q.T. Hao, J.H. Li, Study on process of magnesium alloy investment casting. Mater. Sci. Forum. 561-565 (2007) 1019-1022.

DOI: 10.4028/www.scientific.net/msf.561-565.1019

[6] Z. Zhang, G. Morin, Effect of inhibitor gas on mould-magnesium reactions in investment casting, in: Alen A. Lu, (ed), Magnesium Technology 2004, TMS, USA, 2004, pp.197-202.

[7] H. Jafari, M.H. Idris, A. Ourdjini, M.R. Abdul Kadir, Influence of flux on melting characteristics and surface quality of in-situ melting AZ91D, Mater. Manuf. Process. 28 (2013) 148-153.

DOI: 10.1080/10426914.2012.746787

[8] H. Jafari, M.H. Idris, A. Ourdjini, S. Farahany, In-situ melting and solidification assessment of AZ91D granules by computer-aided thermal analysis during investment casting process. Mater. Design. 50 (2013) 181-190.

DOI: 10.1016/j.matdes.2013.02.035

[9] S. Jones, C. Yuan, Advances in shell moulding for investment casting. J. Mater. Process. Tech. 135 (2003) 258–265.

[10] C. Yuan, S. Jones, Investigation of fibre modified ceramic moulds for investment casting, J. Eur. Ceram. Soc. 23 (2003) 399–407.

[11] N.V. Ravi Kumar, J.J. Blandin, M. Suery, E. Grosjean, Effect of alloying elements on the ignition resistance of magnesium alloys, Scripta Mater. 49 (2003) 225-230.

DOI: 10.1016/s1359-6462(03)00263-x