Laser resolidification of Zn-rich
Zn-Ag peritectic alloys
Zn-Ag peritectic alloys
(1. School of Materials Science and Engineering,
Huazhong University of Science and Technology, Wuhan 430074, China；
2. Department of Materials Science,
National University of Singapore, Singapore 119260)
Huazhong University of Science and Technology, Wuhan 430074, China；
2. Department of Materials Science,
National University of Singapore, Singapore 119260)
Abstract: 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 o f 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 interphases pacing of two-phase couple growth η+ε decreases with increasing laser scanning speed.
Key words: Zn-Ag alloys; laser remelting; peritectic; couple growth