Grain refinement of commercially pure aluminum with addition of Ti and Zr elements based on crystallography orientation

The edge-to-edge matching (E2EM) model and electron back-scatter diffraction (EBSD) technique are used to explore the grain refinement mechanism of commercially pure Al through the addition of Ti and Zr elements. EBSD results show that there are favorable crystallography orientation relationships (ORs) between both Al₃Ti and Al₃Zr particles with α-Al matrix. Due to these ORs Al₃Ti and Al₃Zr particles act as the heterogeneous nucleation site during solidification nucleation of Al-Ti and Al-Zr alloys, respectively. Furthermore, both Al₃Ti and Al₃Zr particles have small values of interplanar spacing mismatch and interatomic spacing misfit with respect to α-Al matrix by using E2EM. It shows that micro-addition of Ti and Zr element is efficient heterogeneous nucleation refiner in commercial purity Al or Al alloys. Besides, there may be some other mechanisms in grain refinement of Al alloys with addition of Ti grain refiner.