放射光を利用した低炭素鋼溶接金属の凝固現象の観察

抄録

Unidirectional solidification process of weld metal for low-carbon steel was characterized by using time-resolved X-ray diffraction system. Ultra bright undulator beam was used as the probe. Since the incident undulator beam was both monochromatic and highly collimated, the reflection plane that satisfied the Bragg condition could reflect the crystal configuration in fusion zone very well. It made it possible crystal orientation analysis under rapid cooling rate. Then the growth morphology and phase transformation for dendrites in fusion zone were directly analyzed. Furthermore it was suggested that nucleation site in solid-state transformation could be elucidated using laser scanning confocal microscopy. It made it possible for complicated microstructure classification to be clear. Developed characterization techniques have potential as a tool for comprehensive analysis for weld solidification and phase transformation in order to progress weld mechanical property.