Zn-19％Al-6％Mg热浸镀层凝固机理及其微观组织演化OA

With the continuous advancement of industry and the increasing demands of daily life,enhancing the service life of materials has become an important research focus.To develop coatings with high corrosion resistance,this study utilized a laboratory hot-dipped galvanizing simulator to prepare a Zn-19％Al-6％Mg coating and simulated its solidification process using Pandat software.The microstructure of the coating was systematically characterized through mang analytical techniques such as glow discharge optical emission spectrometry(GDOES),scanning electron microscopy(SEM),X-ray diffraction(XRD),and differential scanning calorimetry(DSC).The results indicate that the coating primarily consists of primary Al dendrites,MgZn2 intermetallic compounds,and a Zn phase.The solidification process occurs in the following sequence.Primary Al precipitates first,followed by the formation of a binary eutectic structure of Al-MgZn2,and finally the remaining liquid phase transforms into a ternary eutectic structure of Al-MgZn2-Zn.The primary Al is not a single phase but is composed of a core of α-Al phase and a shell eutectoid structure of α-Al and η-Zn.During the solidification of the Zn-19％Al-6％Mg coating,the primary Al phase initially precipitates α-Al at the early stage.Subsequently,the liquid phase undergoes a peritectic reaction with α-Al,forming a high-temperature β-Al phase.As the coating further cools,the high-temperature β-Al phase ultimately undergoes a eutectoid transformation into α-Al and η-Zn phases.