The effect of solidification rate on morphology microstructures and mechanical properties of 80%Cu-20%Sn bronze alloys

I Ketut Gede Sugita*, R. Soekrisno, I Made Miasa and Suyitno

¹Department of Mechanical and Industrial Engineering, Gadjah Mada University, Yogyakarta (Indonesia).

Received on March 10, 2010 and accepted on April 17, 2010

ABSTRACT

The purpose of this study is to investigate the morphology of solidification microstructures 80% Cu-20%Sn on different solidification rate. The commercial pure copper and tin were melted in crucible furnace at temperature 1000oC. The molten metal was casted in permanent moulds which have variation temperature, i.e. 35oC, 200oC, 400oC. The cooling curves of the castings were recorded using a computer aided data acquisition system. The microstructure and mechanical properties of this alloy have been investigated. The results of this research indicate that decreasing the mould temperatures affected on increasing solidification rate that caused to reduce the solidification time. The difference of solidification rate have effected on microstructure morphology. The secondary dendrite arm spacing (SDAS) decreases with increasing solidification rate, the hardness and strength increase correspondingly. The distribution of hardness cast product increased from the center to outside the cast specimens.

Keywords : Tin bronze, dendrite, secondary dendrite arm spacing (SDAS), cooling rate, microstructure.