Effect of Heat Treatment on Corrosion Performance of Mg-12Gd-3Y-1Sm-0.8Al Alloy.

In this work, static mass analysis method and electrochemical test experiment were used to study the corrosion resistance of Mg-12Gd-3Y-1Sm-0.8Al alloy in different heat treatment states. Optical microscope, scanning electron microscope and x-ray diffractometer were used to analyze microstructure. The result shows: The microstructure of different samples are composed of α-Mg, Mg₅Gd, Mg₂₄Y₅, Mg₄₁Sm₅ and Al₂RE phases. Heat treatment can change the morphology and distribution of the precipitates, and the precipitates can affect the corrosion behavior as a cathode, thereby improving the corrosion resistance of the alloy in 3.5% NaCl solution. The relative corrosion rates of the different samples can be ranked as T6>T6-18h>T4>As-cast. After aging treatment, the fine and continuous precipitates act as a barrier to prevent the propagation of corrosion. At this time, the alloy has the strongest corrosion resistance. [ABSTRACT FROM AUTHOR]