For advanced materials characterization, a novel and extremely effective approach of pattern recognition in optical microscopic images of steels is demonstrated. It is based on fast Random Forest statistical algorithm of machine learning for reliable and automated segmentation of typical steel microstructures. Their percentage and location areas excellently agreed between machine learning and manual examination results. The accurate microstructure pattern recognition/segmentation technique in combination with other suitable mathematical methods of image processing and analysis can help to handle the large volumes of image data in a short time for quality control and for the quest of new steels with desirable properties.

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Hydrogen was produced by methanol decomposition over cold-rolled foils of intermetallic compound Ni 3 Al which is known as an excellent high-temperature structural material. We found high catalytic activity and selectivity for methanol decomposition in flat cold-rolled Ni 3 Al foils. The catalytic activity was enhanced above 713 K by the spontaneous formation of fine Ni particles dispersed on carbon nanofibers during the reaction, resulting in high catalytic performance. The results demonstrate that the Ni 3 Al foils can be used both as catalyst precursors and as structural materials of microreactors for hydrogen production.

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In our previous works, thin foils of boron-free stoichiometric Ni 3 Al, with thicknesses ranging from 57 to 315 m, were fabricated by cold rolling of single-crystalline sheets which were sectioned from directionally solidified ingots. In this article, the room-temperature mechanical properties of the 83 and 95 pct cold-rolled foils were examined. Depending on the initial rolling direction, the foils exhibited two types of deformation microstructures: a banded structure with dual {110} textures and a band-free structure with a single {110} texture. The 83 pct cold-rolled foils showed very high Vickers hardness numbers: 649 and 604 for the banded and band-free structures, respectively. The foils possessed very high tensile fracture stress (1.7 to 2.0 GPa), with no appreciable plastic elongation along the rolling direction. The fracture stress of the 95 pct cold-rolled foils was slightly higher than that of the 83 pct cold-rolled foils. The banded-structure foils showed slightly higher fracture stress than the band-free-structure foils at the 83 pct reduction, but there was no difference between both the structures at the 95 pct reduction. Although there was no appreciable tensile elongation, slip traces were clearly observed on the surfaces of the foil specimens after the tensile test, indicating traces of some plastic deformation. The 95 pct cold-rolled foils possessed bending ductility, which was estimated as about 12 pct elongation on the tension-side surface of the bent specimen.

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