Laser resolidification of Zn—rich Zn—Ag peritectic alloys
摘要
Laser remelting experiments were performed by a 1.0kW continuous CO2 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 e surrounded by peritectic η, a two-phase plate-like η+e with primary dendrites of e 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+e decreases with increasing laser scanning speed.