Viscosity variation of hypereutectic Al–Si alloys with high iron contents around liquidus temperature

ABSTRACT

The viscosity of high Fe-containing hypereutectic Al–Si alloys was studied by using a high-temperature Searle-type rheometer. The results show that the steady-state viscosity of Al–17Si–(2,3,4) Fe alloy melts increases with the increase of iron content. During the continuous cooling of Al–17Si–(2,3,4) Fe alloy melts, the transient viscosity increases slowly at the initial stage of cooling. When the temperature decreases to a critical value, the transient viscosity increases abruptly. In the cooling process of Al–17Si–2Fe–(0,0.4,0.8)Mn alloy melts, the steady-state viscosity continues to increase and reach the maximum value firstly, then decreases abruptly, and then continues to increase again. The steady-state viscosity of Al–17Si–2Fe, Al–17Si–2Fe–0.4Mn and Al–17Si–2Fe–0.8Mn alloy melts experiences a sudden decrease at 630°C, 640°C and 670°C respectively due to the settlement of Fe-rich phases. The maximum value of viscosity of the Al–17Si–2Fe–(0,0.4,0.8)Mn alloy melts is increased with the increase of Mn content.

KEYWORDS:

• Viscosity
• hypereutectic Al–Si alloys
• high iron contents

Acknowledgements

The authors would like to express their appreciation to the Analytical and Testing Center, HUST.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant number 51605342] and China Postdoctoral Science Foundation [grant number 2015M572135].