Effect of AlP on the eutectic nucleation in Ni–38 wt.%Si alloys

The eutectic nucleation of Ni–38 wt.%Si alloys with AlP particles addition was investigated in this paper. It is found that AlP and NiSi2 have similar lattice parameters, and the disregistry for the case along the (2 2 0) of AlP particles and the (4 0 0) of the NiSi phase is 6.77 pct, a value which implies good coherency between the two phases. So a new discovery in this study is that AlP particles can act as the nucleation substrate for NiSi2 and NiSi phases, and the addition of AlP particles changes the nucleation mechanism of the Ni–38 wt.%Si alloys. Another discovery is that the addition of AlP particles decreases the driving force for the heterogeneous nucleation (ΔG′k) and the degree of the supercooling (ΔT), and the beginning of the exothermic peak for Ni–38 wt.%Si alloys with AlP particles is 17 °C higher than that without AlP particles addition.