Optimisation of melt pouring temperature and low superheat casting of Al-15Mg₂Si-4.5Si composite

ABSTRACT

In this study, a computational fluid dynamics (CFD) model is employed to optimise the melt pouring temperature during Low superheat casting (LSC) of the Al-15 Mg₂Si-4.5Si composite. The die cavity considered to perform the die filling simulations corresponds to the as-cast tensile specimens, as per ASTM B557 guidelines. The findings of the study include melt temperature distribution, solid fraction distribution during filling as well as during solidification, velocity distribution of the melt and surface defect concentration. Experimentation is performed to develop low superheat cast composite based on the numerically estimated optimum melt pouring temperature of 650°C. Mixture of irregular dendritic, polygonal and equiaxed shaped primary Mg₂Si grains are observed within the cast parts, whereas primary Al grains are found to be of dendritic morphology with occasional presence of spheroids. Marked improvements in microstructure and mechanical properties have been evidenced in the LSC composite compared to its conventional cast counterpart.

KEYWORDS:

• Die filling
• low superheat casting
• Al-15Mg2Si-4.5Si composite
• computational fluid dynamics
• tensile specimen

Acknowledgments

The author would like to thank DST, SERB New Delhi for their financial support to this work via grant no. SB/EMEQ-449/2014. Authors also like to thank Director, IISc for his continuous encouragement and all the members of erstwhile NNMT group, CSIR-CMERI for their cooperation and cordial help towards successful completion of this research work.

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

The work was supported by the Department of Science and Technology, Ministry of Science and Technology [SB/EMEQ-449/2014]