The effect of γ′-martensite on the corrosion resistance of an Fe-Mn-Al-Ni-Cr shape memory alloy in a sodium chloride solution

Abstract

The martensitic phase transformation in iron-based shape memory alloys has a strong influence on the corrosion properties. To investigate the effect of different amounts of martensite, potentiodynamic polarization measurements were conducted on specimens that were subjected to varying prestrain levels prior to the corrosion experiments. While the passive behavior deteriorates with an increasing martensite amount, the observed corrosion damage changes as well. While an entirely austenitic specimen is characterized by a predominantly surface corrosion with some randomly distributed pitting corrosion, the introduction of the martensitic phase results in micropitting and selective corrosion of the martensite plates.