Effect of solidification cooling rate and phosphorus inoculation on number per unit volume of primary silicon particles in hypereutectic aluminium - Silicon alloys

Collected data on derived number per unit volume N̄v of primary silicon particles in hypereutectic Al-Si alloys show a power relationship with solidification cooling rate Ṫ of the form N̄v = AṪn where typically n ∼ 1 and A ≃ 130 mm-3 (K/s)-1 in the absence of phosphorus and A ≃ 720 mm-3 (K/s)-1 in its prescence. Significantly lower apparent values of N̄v from one set of results appear to stem from measurement of a mean long dimension rather than diameter of particle sections as well as lower measured undercoolings than in Bridgman experiments at similar Ṫ.