INFLUENCE OF HEAT TREATMENT ON THE CORROSION PROPERTIES OF WE43 MAGNESIUM ALLOY DOPED WITH RARE EARTH ELEMENTS

Abstract

This paper investigates the impact of heat treatment (T5) on the structure of magnesium alloy WE43. The study employs physicochemical research methods, including scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray phase analysis.  The results indicate that the surface of WE43 alloy exhibits a reticulated microstructure consisting of α-Mg and β-Mg phases that contain rare-earth elements (Y - up to 3.7 wt.%; Nd - up to 1.1 wt.%). The microstructure of heat-treated alloy WE43-T5 comprises of α-Mg phase and evenly distributed phases of globular and plate-like forms. The studied samples exhibit contrasting regions related to metallic phases of alloying elements (Mg41Nd5, Mg12Nd, Mg5Gd, MgY, Mg24Y5). The corrosion behavior of WE43 and WE43-T5 alloys was studied in model solutions that simulate the bone tissue environment using a set of electrochemical methods. The solutions used were Hank's solution with a pH of 7.4 and acidified Hank's solution with a pH of 5.0, which corresponds to the injured state of bone tissue. The study focused on the effects of heat treatment on the corrosion of magnesium alloys. The study found that the heat treatment process of magnesium alloy WE43 reduced the corrosion rate by 4.4 times and 2.7 times in Hank's solutions with pH 7.4 and pH 5.0, respectively. The exponential values n1 and n2 are shown to be in the range 0.81 to 0.97. Values close to 1 indicate that the constant phase element models the impedance of the distributed capacitive element. Heat treatment results in a 2.5-fold increase in the polarization resistance of the WE43 alloy in Hank's solution (pH=7.4). However, in Hank's solution (pH=5.0), the polarization resistance of the heat-treated alloy decreases by 68%. The Rp values of WE43 and WE43-T5 samples in Hank's solution (pH=5.0) are similar. For citation: Paspelau A.V., Kasach A.A., Kurilo I.I., Tsyganov А.Р. Influence of heat treatment on the corrosion properties of we43 magnesium alloy doped with rare earth elements. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 5. P. 128-135. DOI: 10.6060/ivkkt.20246705.7076.