Effect of Hot-Pressing Treatment on the Microstructure and Corrosion Resistance of Mg-Zn Alloy Prepared by Gas Phase Alloying Method

Abstract

In order to effectively improve the properties of magnesium alloys， the effects of Zn on the microstructure and corrosion behavior of magnesium alloys under two states of condensation and hot-pressing were explored.The Mg-Zn binary alloy was prepared by gas phase alloying method， and the alloy was studied and analyzed by optical microscopy (OM)， X-ray diffraction (XRD)， scanning electron microscopy(SEM)， energy dispersive X-ray spectroscopy (EDX) and electrochemical workstation.Results showed that the phases of alloy under two states of condensation and hot-pressing were composed of α-Mg， MgZn， Mg7Zn3 and MgZn2 phases.After hot-pressing treatment under the conditions of 300～360 ℃＋10 MPa＋40 min，the microstructure of the alloy became more uniform and denser，which also gradually formed strip structure.With increasing the hot-pressing temperature， the corrosion current density of the alloys decreased， and the corrosion resistance increased.When the time of the hot-pressing treatment extended from 4 h to 12 h at 320 ℃， the degree of the plastic deformation of alloy obviously enhanced， and the fine Mg7Zn3 phases were precipitated and presented the uniform distribution.Besides， the corrosion resistance of the as-obtained alloy was weakened.

Keywords

• mg-zn alloy|gas phase alloying|hot-pressing|corrosion resistance