Influence of cerium on the formation of micro-galvanic corrosion elements of AZ91

Research output: Contributions to collected editions/worksArticle in conference proceedingsResearchpeer-review

Authors

  • Daniela Zander
  • Meredith Heilig
  • Norbert Hort
  • Gerald Klaus
  • Andreas B̈hrig-Polaczek
  • Joachim Gröbner
  • Rainer Schmid-Fetzer

Investigations of AZ91D revealed a strong influence of mainly the following microstructural parameters on corrosion: porosity, the eutectic, the Al-content of the Mg-phase as well as the volume fraction and distribution of gamma-Al12Mg17. Further an improved corrosion resistance was observed by the addition of rare earth elements. The influence of Ce on microstructure and corrosion of sand cast and high pressure die cast AZ91D with 0.5-2.0 wt.% Ce was investigated by SEM before and after potentiodynamic polarization measurements in pH7.5 (bi-distilled water adjusted with KOH). It was observed that Ce significantly improved the corrosion resistance by changing the microstructure. A strong influence of Ce on the average grain size, the fraction of the eutectic, changes in morphology and/or volume fraction of gamma Al12Mg17 and formation of a Cerich intermetallic phase was observed. Therefore, not only the chemical composition but also the change of microstructure and the formation of micro-galvanic elements influence the local corrosion mechanism of AZ91D with cerium.

Original languageEnglish
Title of host publicationLight Metals Technology V
EditorsHajo Dieringa, Nobert Hort, Karl Ulrich Kainer
Number of pages4
PublisherTrans Tech Publications Ltd
Publication date2011
Pages381-384
ISBN (print)9783037851807
DOIs
Publication statusPublished - 2011
Externally publishedYes

    Research areas

  • AZ91D, Cerium, Corrosion, Microstructure
  • Engineering