Development at temperature mrasurment system and solidification microstructure control under rapid solidification condition

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Rapid solidification processing is expected to develop new near net shape methods and to bring out new functional properties by making fine structures, supersaturation, metastableand amorphous phases. To develop further rapid solidification processing, it is necessary to under stand deeply rapid solidification phenomenaby introducing appropriate measuring methods and also to simulate phenomena. This research is aimed 1) to predict quantitatively morphology and phase selection, and segregation, 2) to make clear a guide line to develop the rapid solidification processing of structural and also magnetic materials. Results obtained are as follows ;1) Morphology and phase selection are established, especially for alloys with peretectic reactions.2) Solidification of rapidly solidified powders is simulated under the conditions of undercooling, diameter of powders and heat transfer between ambientgas and powders.3) Crystal growth model is developed by incorporating empirical nucleationequations occurred between in got and mold surfaces.4) Phase selection is modeled for Nd-Fe-B magnets. The condition of producing primary phase Nd_2Fe_<14>B is established controlling solidification rate and initial composition.5) Solidfication path is established for Nd-Fe-B magnets. The amount of Nd_2Fe_<14>B and boundary phases can be predicted.