High undercooling of Ni[sub 59]Nb[sub 41] alloy in a containerless electrostatic levitation facility.

Utilizing the containerless electrostatic levitation facility at NASA/MSFC, we were able to undercool the Ni[sub 59]Nb[sub 41] (atomic) alloy by 210 K which was 160° farther than the results of previous flight experiments. Undercoolings were clustered around 200 K during the repeated melting-freezing cycles on a single sample. Prior to this work, a metastable liquid separation had been presumed to limit the undercooling of this alloy. However, microstructural observations have revealed that undercooling was limited by crystal nucleation. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]