Investigation of the degradation rate of electron beam processed and friction stir processed biocompatible ZKX50 magnesium alloy

Fatemeh Iranshahi*, Mohammad Bagher Nasiri, Fernando Gustavo Warchomicka, Christof Sommitsch

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Together with the mechanical properties, the degradation rate is an important factor for biodegradable implants. The ZKX50 Mg alloy is
a suitable candidate to be used as a biodegradable implant due to its favorable biocompatibility and mechanical properties. Current research
investigates the degradation rate and corrosion behavior of the ZKX50 as a function of the microstructure constituents and their morphology.
Since grain refinement is the main strengthening mechanism for the ZKX50, the effect of the microstructure refinement on the corrosion rate
was studied by applying electron beam processing (EBP) and friction stir processing (FSP) on the ZKX50 cast alloy. To study the effect of the
microstructure constituents and their morphology a subsequent solution heat treatment (HT) was applied to the processed samples. The results
show that the EBP and FSP lead to a uniform and remarkably refined microstructure of the ZKX50 alloy and homogeneous distribution of the
intermetallic phases. The results of electrochemical corrosion tests together with the microstructure characterization show that microgalvanic
corrosion is the predominant mechanism that occurs between the Ca 2 Mg 6 Zn 3 intermetallic phase and α-Mg matrix. According to the results
attained through the electrochemical tests, the EBPed-HT ZKX50 alloy shows higher corrosion resistance compared to all other conditions
immersed in 0.5 wt% NaCl solution. The dissolution and spheroidizing of Ca 2 Mg 6 Zn 3 particles during the solution heat treatment provides
higher corrosion resistance mainly by decreasing the microgalvanic corrosion. The microstructure of the heat-treated samples does not show
a significant grain coarsening which can degrade the enhancement of the mechanical properties achieved by the EBP and FSP.
Original languageEnglish
Pages (from-to)707-720
Number of pages14
JournalJournal of Magnesium and Alloys
Volume10
Issue number3
DOIs
Publication statusPublished - 2022

Keywords

  • Magnesium alloys
  • Electron beam processing
  • Friction stir processing
  • Corrosion
  • Biodegradable metals

ASJC Scopus subject areas

  • Mechanics of Materials
  • Metals and Alloys

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