In order to overcome the brittleness of Nb-Si intermetallic compounds, a novel microstructure control through a eutectic solidification and a eutectoid decomposition reactions has been proposed for obtaining Nb matrix alloys with Nb-silicide dispersion by the present authors. As the additions of Zr and Mg accelerate the eutectoid decomposition rate and spheroidization of Nb-silicide during heat treatment, the effects of these additives on the eutectic microstructure are investigated. The effect of the growth rate during the uni-directional solidification on the microstructure of a selected alloy was examined and it was found that the following eutectoid reaction rate is strongly affected by the growth rate.

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Roll bending is a useful technology for manufacturing a wide variety of products in small quantities. However, the roll bending of structural channels, which have a complicated sectional shape, causes irregular deformation. On the other hand, there are fewer reports on the bending of structural channels compared to those on the roll bending of sheet-metals. The purpose of this study is to clarify the deformation behavior in the roll bending of structural channels. The present paper reports on the results from a finite element analysis of the effects of the roller shape on the deformation behavior in the roll bending of structural channels.

Roll bending is a useful technology for manufacturing a wide variety of products in small quantities. However, the roll bending of structural channels, which have a complicated sectional shape, causes irregular deformation. On the other hand, there are fewer reports on the bending of structural channels than those on the roll bending of sheet metals. The purpose of this study is to clarify the fundamental forming property in the roll bending of structural channels. In the present paper, we report the results of a finite element analysis of the effects of the processing conditions, that is, the distance between the side rollers and the displacement of the side rollers, on the deformation behavior in the three-roll bending of structural channels.

No abstract