| Abstrakt: |
This research investigates the effect of solution treatment on the microstructure and corrosion resistance of the Mg–5Zn–1.5Y alloy as a biodegradable biomaterial. Thermal analysis, optical and electron microscope images, as well as energy dispersive analysis and elemental analysis, were used to evaluate the microstructure and phases present in the pre- and post-heat treatment. To evaluate the corrosion behavior of cast and solved samples, a polarization test was performed in simulated body fluid (SBF), and the potential, current density and corrosion rate of each sample were calculated. The results indicate that the solution treatment at 415 °C temperature leads to the dissolution of the secondary phases I (Mg3Zn6Y) and W(Mg3Zn3Y2) present in the microstructure and the formation of a magnesium matrix supersaturated of alloying elements, and increasing the solution time reduces the volume fraction of these precipitations. These microstructural developments have resulted in a decrease in the formation of galvanic micro-piles between the matrix and intermetallic compounds present in the microstructure, leading to a decrease in the corrosion rate of the alloy from 10.5 mm/y in the cast sample to 1.87 mm/y in the dissolved sample after 50 h. Based on the results obtained, the main reason for this phenomenon can be attributed to the role of secondary phases present in the microstructure in the corrosion process. |
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