Rotation of the crystal orientation of a laterally grown grain in Si thin film was investigated with the micro-chevron laser beam scanning (μCLBS) method. The rate of orientation rotation Rθ was found to be inversely proportional to Si film thickness tSi, and a model to explain the orientation rotation was proposed. The rotation is caused by a 2.2% difference in expansion rate between the top and bottom surfaces of the Si film on solidification. An SiO2 capping film was used to suppress rotation, and as a result, a twin-free (100)-faced single-crystal Si stripe longer than 3 mm was formed. It was found that all sustainably grown grains had Rθ = 0, and all were (100) in the normal direction. This result shows that (100) is the only orientation for stable lateral crystal growth in thin film.

Each Japanese sword is unique by its microstructure resulted by the steel composition and heat treatment. In this study, the automatic reconstruction method was applied for characterizing the prior-austenite microstructure at the sharp edge of three Japanese swords made in different time periods. The reconstructed prior-austenite microstructure was compared with that of three carbon steels, in order to clarify the variations of carbon content and heating temperatures of the swords. It was found that in carbon steels, the austenite microstructure is probably affected by initial microstructures, which is predominantly determined by carbon content. The three swords have similar carbon content, but their prior-austenite microstructures are considerably different, probably due to their heating temperatures. The strength at the sharp edge of the modern sword is significantly higher than that of the old sword. It may be due to the fine-grained prior-austenite in the modern sword compared with the abnormally coarse grains observed in the old sword. In order to obtain fine-grained austenite along with high strength and hardness of the cutting edge, it is recommended that the carbon content of Japanese sword is 0.60.7 mass%, and the heating temperature is from 750 to 800°C.

The lath martensite structure contains hierarchical substructures, such as blocks, packets and prior austenite grains. Generally, high-angle grain boundaries in the lath martensite structure, i.e. block boundaries, are correlated to mechanical properties. On the other hand, low-angle grain boundaries play an important role in morphological development. However, it is difficult to understand their nature because of the difficulty associated with the characterization of the complex morphologies by two-dimensional techniques. This study aims to identify the morphologies of low-angle boundaries in ultra-low carbon lath martensite. A serial-sectioning method and electron backscatter diffraction analysis are utilized to reconstruct three-dimensional objects and analyse their grain boundaries. A packet comprizes two low-angle grain boundaries - sub-block and fine packet boundaries. Sub-blocks exhibit porous morphology, with two large sub-blocks predominantly occupying a block. Several fine packets with different habit planes from the surrounding regions are observed. Fine packets are present in blocks, which frequently share a close-packed direction with the neighbouring fine packets. In addition, fine packets are in contact with the sub-block boundaries.

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