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We present a new microstructure dataset consisting of ultrahigh carbon steel (UHCS) micrographs taken over a range of length scales under systematically varied heat treatments. Using the UHCS dataset as a case study, we develop a set of visualization tools for interacting with and exploring large microstructure and metadata datasets. Based on generic microstructure representations adapted from the field of computer vision, these tools enable image-based microstructure retrieval, as well as spatial maps of both microstructure and related metadata, such as processing conditions or properties measurements. We provide the microstructure image data, processing metadata, and source code for these microstructure exploration tools. The UHCS dataset is intended as a community resource for development and evaluation of microstructure data science techniques and for creation of microstructure data science teaching modules.

This study was undertaken to investigate the effect of small amounts of copper and copper + nickel additions on the oxidation rate and oxide/metal interface microstructure of iron. Three iron-based alloys were compared: 0.3 wt pct copper, 0.3 wt pct copper-0.1 wt pct nickel, and 0.3 wt pct copper-0.05 wt pct nickel. Alloy samples were oxidized in air at 1150°C for 60, 300, and 600 seconds. Pure iron oxidized for 300 seconds was used as a reference material. The parabolic oxidation rate for the iron-copper alloy did not differ from that of pure iron, but the parabolic rate for the nickel-containing alloys decreased by a factor of 2. The microstructure of the iron-copper alloy consisted of a thin, copper-rich layer at the oxide/metal interface. Both nickel-containing alloys had perturbed oxide/metal interfaces consisting of alternating solid/liquid regions. The application of ternary alloy interface stability theories show that the perturbed interfaces arise from unequal diffusivities in the solid c-iron phase. It is suggested that this perturbed interface microstructure causes the observed decrease in oxidation rate, by limiting the iron supply to the oxide.

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