| Abstrakt: |
Hexagonal martensite α′ has special metallographical corrosion behavior: the inner microstructure of some grains shows unobvious contrast after corrosion, while some other grains have obvious corrosion character, namely the inner vimineous α′ array orthogonally. In the present work, the mechanism of this corrosion behavior was studied based on OM, AFM and EBSD analyses. Results show that there are three groups of orthogonal precipitation directions of α′ transforming from original β phase. If the metallographical observation surface is parallel or nearly-parallel to any one of the three groups of orthogonal precipitation directions, then this group of α′ plates must array orthogonally or parallelly. Under this circumstance, α′ plates are perpendicular to the observation surface, thus the α′/α′ interfaces are deep, which leads to deep corrosion depth, and finally deep corrosion characters are shown. For a given grain, the two arrangement modes of α′ plates can exist simultaneously, which shows a orthogonal array mode as a whole. [ABSTRACT FROM AUTHOR] |
