<p>The influence of 0.1 wt.% Ti and Ti/B on Zn–6 wt.% Al–3 wt.% Mg coating alloy during rapid cooling (50–75&#xa0;°C/s) was investigated. The results demonstrate a significant change in the microstructure of the alloy upon the introduction of Ti or Ti/B. Al dendrites undergo a transition from slender to short and coarse, and more Al dendrites are produced. The ternary eutectic Zn/Al/Mg₂Zn₁₁ phase is no longer observed, while only the ternary eutectic Zn/Al/MgZn₂ phase is present. The addition of Ti results in the formation of a precipitated phase consisting of TiAl₃ and when Ti/B is added, both TiAl₃ and TiB₂ phases are observed to precipitate. The solid solubility of Mg in Zn can be influenced by Ti, as demonstrated through composition profile, thermodynamic calculation, and diffusion couple experiments. Zn phase nucleates as the priority phase when the eutectic phase precipitates. Due to the significant supercooling, rapid growth of Zn phase occurs, accompanied by solid dissolution of some Mg and Al into Zn phase because of insufficient time for diffusion outside. The interface of Zn phase exhibits a low concentration of Mg, resulting in the formation of Mg₂Zn₁₁ nuclei. After the solid solution of Ti in Zn phase, more Mg and Al will be discharged, and MgZn₂ nuclei will be generated at the higher concentration of Mg at the interface of Zn phase. By elucidating the solidification mechanism, a deeper comprehension of the role of Ti in Zn–6Al–3Mg alloy can be attained.</p>