Effect of antimony additions on hardness and tensile properties of directionally solidified Al–Si eutectic alloy

The effect of antimony additions on the hardness and tensile properties of Al–Si eutectic alloy has been examined during directional solidification. Antimony, provided that its concentration in the melt was maintained at ∼0·1 wt-%, improved the mechanical properties of the eutectics by almost 20–25%, all effects being additive to those that can be gained through increasing the growth velocity of the samples. Mechanical properties were found to correlate directly with the spacing between the silicon particles of the eutectic phase of the solidification structure, a Hall–Petch type relationship existing between the yield strength and silicon particle spacing.

MST/653