Influence of Microstructure on the Corrosion Resistance of AZ91D after EB Surface Alloying

Abstract:

This paper focuses on liquid phase surface treatment of the Mg alloy AZ91D by electron beam alloying (EBA) using Al-based additives to improve, primarily, the materials corrosion resistance, as well as its hardness. By variation of EB energy input, layer depths between 0.7 and 2.5 mm were generated. As a result, layers with different Al contents were produced, and were categorized into three different types of microstructure. A correlation could be observed between these three types of microstructure and hardness, as well as between microstructure and corrosion behaviour. Hardness was improved by approximately 2 to 4 times from 67 HV0.1 (base material) up to 140-250 HV0.1 (EBA layer). For high Al contents, the corrosion potential could be increased by about 400 mV compared to the base material. Moreover, it is shown that, after a homogenization process, a corrosion potential of 450 mV above the corrosion potential of the base material was achieved even for low Al contents.

• Periodical: Materials Science Forum (Volume 765)
• Pages: 607-611
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.765.607
• Online since: July 2013
• Authors: Katja Fritzsch, Anja Buchwalder, Rolf Zenker, Marco Klemm
• Keywords: Alloying, Corrosion, Electron Beam, Microstructure, Surface Treatment

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