The influence of rare earth cerium addition on mechanical and corrosion properties cast Mg-6Al-1Zn magnesium alloy

Abstract

The present study investigates the effect of Ce addition on the microstructure of Mg-6Al-1Zn alloy with the use of optical microscopy (OM), X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The electrochemical corrosion behaviour of Mg-6Al-1Zn alloyed with different levels of cerium was investigated using static weight loss and polarization corrosion tests in 3.5% NaCl solution. The microstructural study reveals the grain refinement of the matrix and the stability of the phase β(Mg17Al12) were disintegrated into Al4Ce and distributed along the grain boundary. The literatures show that the intermetallic Al4Ce has a high melting point and expected to show better strength behaviour at relatively high temperatures. The electrochemical results show that cerium addition above 1.5wt.% increase the corrosion current density of the developed alloy which resulted in increasing corrosion rate. The best results of refined microstructure and corrosion resistance were obtained with 1.5wt.% cerium addition.