An ultrahigh speed imaging system has been developed and built to image rapid solidification of materials. The system collects data from a 10 by 10 array of parallel tapped photodiodes. Up to 8192, frames of data are digitized with 8-bit flash converters at frame rates ranging from 500 to 1 000 000 frames per second. The system has been used to image solidification of a gamma titanium aluminum (&ggr;-TiAl) alloy, with compositionTi-60a/oAl, over a range of undercoolings. The data collected includes the first images of solidification from multiple solidification fronts, images of solidification of a disordered phase followed by the alloy ordering, and quantitative measurement of solidification velocity as a function of undercooling in a &ggr;-TiAl alloy. ©1997 American Institute of Physics.