LI Jianguo MAO Xiemin FU Hengzhi National Laboratory of solidification Technology
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Northwestern Polytechnical University
,
Xi'an
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China Lecturer.Faculty No.403
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Northwestern Polytechnical University
,
Xi'an 710072
,
China
金属学报(英文版)
The interface morphologies and microstruetures of the directionally solidified Ni-5wt-% Cu alloy during dendrite-to-cell transition at high growth rates have been investigated with a newly developed apparatus for unidirectional solidification with the temperature gradient at the solid/liquid interface higher than 1000 K/cm.The results show that in the vicinity of dendrite-to-cell transition point,the well developed sidebranches become shrivelled with the increase of growth rate and disappear at the dendrite-to-cell transition,and the primary spacing decreases simultaneously.Moreover,the length of mushy zone decreases greatly dur- ing the dendrite-to-cell transition.Cells obtained at high growth rates have very similar morphologies to those at low growth rates,but with much smaller cell spacings and unsmoothed cell walls which may be attributed to the different stability conditions of the cell walls at low and high growth rates respectively.
关键词:
cellular growth
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null
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null
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李建国
,
毛协民
,
傅恒志
金属学报
本文利用新研制的ZMLMC定向凝固装置,研究了Ni-5wt-％Cu合金快速定向凝固条件下由树枝状生长转变为胞状生长及其过渡过程的凝固界面结构和微观组织。实验结果表明:在枝-胞转变点附近,随生长速率的增大,侧向分枝由发达逐渐萎缩,最终消失;同时一次枝晶间距减小,发生枝-胞转变时,糊状区长度急骤缩短。快速生长胞状界面与慢速生长胞状界面形态相似,但前者胞间距更小,且胞壁不光滑。
关键词:
胞状生长
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interface morphology
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primary spacing
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rapid solidification
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dendrite-to-cell transition
