Analysis on phase selection and microstructure evolution in directionally solidified Zn-Al-Mg-Ce alloy

In the process of hot-dip Zn-Al-Mg alloy coating, plating solution dissipates heat in direction perpendicular to steel plate, which is considered be a directional solidification. To understand relationship between microstructure and cooling rate alloys, both phase constitution characteristic length scales Zn-9.5Al-3Mg-0.01Ce (wt.%) were investigated by solidification experiments at different growth velocities (V=40, 80, 160, 250 µm·s−1). The experimental results show that directionally solidified composed primary Al dendrites (Zn-Al-Mg2Zn11) ternary eutectics ranging from 40 µm·s−1. are aligned regularly along direction, accompanied with obvious secondary dendrites. scale thermal parameters obtained: λ1=374.66V−0.383, λ2=167.5V−0.563 (λ1 dendrite arm spacing, λ2 dendrit spacing). addition, through interface response function (IRF) nucleation constitutional undercooling (NCU), selection (Zn+Al+Mg2Zn11) will replaced (Zn+Al+MgZn2) when lower than 7.53