Effect of Ti on Morphology and Growth of Zn–Fe Intermetallic Phases

The effect of Ti in Fe substrate on the morphology and growth of Zn–Fe alloy phases in (Zn–0.2 wt.%Al)/Fe diffusion couples was investigated using optical and scanning electron microscopy. It is shown that ζ phase layer does not exist in (Zn–0.2 wt.%Al)/Fe couple, but it can be clearly observed in (Zn–0.2 wt.%Al)/(Fe–Ti) diffusion couples. Increasing of dissolved Ti in Fe substrate delays the disappearance of the ζ phase and promotes the formation of δk phase. The δp phase grows toward the ζ phase layer in the form of arborescence. The growth of total intermetallic phase layers in all diffusion couples is controlled by diffusion of Zn and Fe atoms within the layers at 380 °C. The thickness of total intermetallic layer increases with increasing of dissolved Ti in Fe substrate and reaches the maximum when Ti content is 0.4 wt.%.