摘要
The structural evolution of undercooled single-phase Ni-2wt%Pb monotectic alloy was systematically investigated by the method of molten glass denucleating combined with superheating cycle. Within the achieved undercooling range of 22 to 280 K, the solidification structure undergoes three changes at 22 K, 88 K and 187 K, respectively. With the increase of undercooling, common dendrites, the first class granular grains, undercooled dendrites and the second class granular grains come out one after the other. Analytical results show that the granulation mechanism of the first class granular grains is owing to dendrite remelting and recrystallization, and the granulation mechanism of the second is owing to dendrite break-up and recrystallization.
The structural evolution of undercooled single-phase Ni-2wt%Pb monotectic alloy was systematically investigated by the method of molten glass denucleating combined with superheating cycle. Within the achieved undercooling range of 22 to 280 K, the solidification structure undergoes three changes at 22 K, 88 K and 187 K, respectively. With the increase of undercooling, common dendrites, the first class granular grains, undercooled dendrites and the second class granular grains come out one after the other. Analytical results show that the granulation mechanism of the first class granular grains is owing to dendrite remelting and recrystallization, and the granulation mechanism of the second is owing to dendrite break-up and recrystallization.
基金
the National Natural Science Foundation of China(Grant No:59871041)and the Natural Science Foundation of Shaanxi Education Admin
