In situ studies of precipitate formationin Al-Pb monotectic solidification by X-ray transmission microscopy

摘要: Al-1.5 wt pct Pb monotectic alloys were unidirectionally solidified. X-ray transmission microscope (XTM) observations, both during and after solidification, revealed various new morphological/compositional features in the melt solid. In melt, nonuniform lead-rich interfacial segregation layers droplets observed to form well ahead of interface. solid, periodic striae formed at translation/solidification velocities as low 6 × 10−6 m/s. The shape does not replicate that spacing decreases from 4 2 10−4 m with an increasing solidification rate between 16 High resolution postsolidification XTM examination reveals these consist Pb-rich particles 3 diameter. At below m/s, incorporation into solid occurs continuous fibers strings about 5 Bands, parallel interface, which aligned direction, alternated bands poor fiber alignment. width is comparable spacings obtained high rates.