先进材料疑固实验室 Formation of equiaxed grains Laboratory of Advanced Materials Solidification When the magnitude of dT(x)/drlo constitutional undercooling is T(x) sufficiently large,new crystals can △Tt nucleate in front of the dendrite trunks. Since the new crystals are in the middle of an undercooled liquid, dendrites can grow in all possible preferred crystallographic directions. Transition from dendritic columnar ⊕ This causes formation of equiaxed growth to dendritic growth of grains. equiaxed grains The figure is from徐洲，姚寿山主编，《材料加工原理》科技出版社，2003. p70 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITYFormation of equiaxed grains When the magnitude of constitutional undercooling is sufficiently large, new crystals can nucleate in front of the dendrite trunks. Since the new crystals are in the middle of an undercooled liquid, dendrites can grow in all possible preferred crystallographic directions. This causes formation of equiaxed grains. The figure is from 徐洲, 姚寿山主编,《材料加工原理》科技出版社, 2003. p70