Our SEM and TEM studies revealed that the dendrites in FeNi–FeS eutectic nodules/blobs in both shock-produced melt veins and melt pockets of the Yanzhuang meteorite show zoning in their microstructures, which indicates non-equilibrium solidification of metal phase. In melt veins, three asymmetric microstructural and compositional zones: core, Ni-rich rim and martensite between the core and ring were discovered, while in melt pockets, a typical symmetric core-crust microstructure consisting of martensitic interiors and Ni-rich rim was revealed. It is suggested that the difference in cooling rates following shock-induced high-temperature melting might be an important factor in producing different dendritic microstructures in melt veins and melt pockets. The solidification environment might be considered as the second influence factor.
FeNi metal Eutectic blob Dendrite Zoning microstructure Martensite
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