Crystal Growth Due to Recrystallization upon Annealing Rapid Solidification Microstructures of Deeply Undercooled Single Phase Alloys Quenched before Recalescence

摘要

Crystal growth due to recrystallization in rapidly solidified microstructures was experimentally observed. Deeply undercooled Ni?Cu alloy melts were quenched before rapid solidification by Ga?In liquid alloy. After the quenching, partially recrystallized microstructures were obtained and further investigated by means of electron backscattering diffraction and transmission electron microscopy. Dense crystalline defects such as dislocation networks which are typical characteristics of deformation microstructures were observed. After the partially recrystallized microstructures were annealed at different temperatures, further recrystallization in the microstructures was observed. However, few crystalline defects were observed in the naturally cooled alloy with the same undercooling. After rapidly solidified microstructures of the naturally cooled alloy were annealed at identical annealing conditions, no recrystallization was observed. With these directly observed experimental results, a new way to prepare microstructures by crystal growth through recrystallization in rapid solidification microstructures is found.