Laser resolidification of Zn-rich Zn-Ag peritectic alloys

Laser remelting experiments were performed by a 1.0?kW continuous CO 2 laser to investigate the rapid solidification behavior of Zn rich Zn Ag peritectic alloys. Three kinds of microstructures occurrs with the varying of laser scanning speed and Ag content in the alloys. It is mainly plate like single phase cellular η when the Ag content was lower than 1.8% (mole fraction). As the Ag content increased, instead of typical structure of primary dendrites of ε surrounded by peritectic η , a two phase plate like η+ε with primary dendrites of ε is found when the laser scanning speed was higher than a critical value. Intercellular spacing of cellular η or interphase spacing of two phase couple growth η+ε decreases with increasing laser scanning speed.