Nucleation potency prediction of LaB6 with E2EM model and its influence on microstructure and tensile properties of Al-7Si-0.3Mg alloy

The edge-to-edge matching (E2EM) crystallographic model was used to predict the orientation relationships (ORs) between LaB₆ and Al. Three different possible ORs can be predicted between LaB₆ and Al, which are${\left(100\right)}_{\text{Al}}6{\left(100\right)}_{{\text{LaB}}_{\text{6}}}$,${\left[001\right]}_{\text{Al}}6{\left[001\right]}_{{\text{LaB}}_{\text{6}}}$;${\left(110\right)}_{\text{Al}}6{\left(110\right)}_{{\text{LaB}}_{\text{6}}}$,${\left[001\right]}_{\text{Al}}6{\left[001\right]}_{{\text{LaB}}_{\text{6}}}$; and${\left(111\right)}_{\text{Al}}6{\left(111\right)}_{{\text{LaB}}_{\text{6}}}$,${\left[01\overline{1}\right]}_{\text{Al}}6{\left[01\overline{1}\right]}_{{\text{LaB}}_{\text{6}}}$. The prediction results are perfectly confirmed through TEM analysis and prove the nucleation potency of LaB₆. The refining efficacy of Al-2La-1B refiner and its influence on the tensile properties were investigated in the as-cast Al-7Si-0.3Mg alloy. According to the results, LaB₆ has higher nucleation potency than TiB₂, leading to better grain refining efficacy of Al-2La-1B refiner in the as-cast Al-7Si-0.3Mg alloy. Regarding the mechanical performances, tensile properties of the as-cast Al-7Si-0.3Mg casting alloy are prominently improved after addition of Al-2La-1B refiner, due to the refined microstructures.